# Solar electric 6.5kw expanded to 12.3kw



## jebatty

It may go on live today! ... and it will be cloudy. A few pictures of the system. 26 Suniva panels, micro-inverters, data-logging controller with wi-fi and hard-wired ethernet, underground wiring to the house. If live today, unfortunately I will not be home when switched on. Have to be out of town for a meeting.


----------



## peakbagger

The racking system look impressive. Is the angle adjustable for seasons? I am little surprised that they mounted them so low, normally I see snow area systems mounted higher to accommodate snow accumulation.

I assume that the system feeding into the grid via "line side tap" (not through the main breaker panel).


----------



## semipro

NIce!  I'm severely envious.


----------



## begreen

That's pretty exciting! What inverters are you using, Enphase?


----------



## Where2

I don't think running your dryer is so much of an issue once you get those 26 panels on-line... 

I guess I'm a little surprised you already have three different electric meters before you add the SREC meter. (one meter is presently removed for safety to the left of the new big red disconnect lever; the SREC meter will go to the right of the new red disconnect lever).


----------



## BrotherBart

If you have the same clothes dryer I have it will knock it to its knees at 5,000 watts. Intermittent for sure but only after it warms the thing up. My head explodes watching the whole house monitor when I use the dryer. Seldom.


----------



## jebatty

> I am little surprised that they mounted them so low, normally I see snow area systems mounted higher to accommodate snow accumulation.


 You have a good point but I doubt snow will be a problem, unless climate change moves us into a high snow belt. Our winters are cold but snow fall usually is pretty light, with most occurring in March when the melt is starting to take good hold. Last winter was an exception when Mar and Apr was very heavy, something I have not seen before in the past 25 years. The grass you see by the panel array is about 4-5 feet high.



> I assume that the system feeding into the grid via "line side tap" (not through the main breaker panel).


 Did you see all the meters and boxes on the side of the house? There are at least two shut-offs, one at the panels and another at the house. Since I was gone yesterday when the system went active, I need to talk with the electrician to bring me up to speed on all the panels and controls.



> What inverters are you using ...


 Aurora Power-One Micro 0.25



> I guess I'm a little surprised you already have three different electric meters before you add the SREC meter.


 The pre-solar meters were general service, dual heat (interruptible) for electric space heating, and off-peak for electric hot water. The off-peak meter is removed and off-peak supply now is via the dual-heat meter, resulting in a still low but slightly higher rate than off-peak.

I have the monitoring panel, which will communicate through the web or directly to my computer, but it is not yet installed. It communicates with and collects data from each of the 26 panels.


----------



## Vic99

Looking good.

I have 25 suniva panels with micro inverters.  Yesterday was exactly 1 year after I went live.  The installer predicted between 5-6 MW for a year.  I got 6.4.  Very pleased.

April was my best month.  Somewhat low temperatures, longer days, and still no leaves for shading.

Good luck.


----------



## jebatty

The panel communication device is Aurora and looks pretty sophisticated. The array is too far from my router to establish a solid wi-fi connection. Bummer. Fortunately, I foresaw this possibility, and an ethernet cable also was buried underground when the electric was put in underground. Need to get some connectors and test it out. Talked to the power company, and possibly on Tuesday someone will be out to OK the system.  A friend also put in a system with Suniva panels earlier this summer, and he says his too is performing better than expected.


----------



## Where2

jebatty said:


> The pre-solar meters were general service, dual heat (interruptible) for electric space heating, and off-peak for electric hot water. The off-peak meter is removed and off-peak supply now is via the dual-heat meter, resulting in a still low but slightly higher rate than off-peak.



Those interrupter boxes look just like the one stationed next to my central A/C compressor unit. We haven't gone to multi-tier pricing in Florida yet. (thankfully). I only have one meter for everything, because we also don't have SREC's. 

My Enphase setup is still so new (at only 11 weeks since going live) that I still check it multiple times a day to see how much energy I'm generating. This weekend will be curious. It's finally cool enough to open the windows in South Florida. If it's sunny, I might actually over produce.


----------



## peakbagger

FYI, new panels will overproduce initially, they degrade rapidly when first exposed to sun so the manufacturers put in some margin in the ratings, after few months in summer the curve levels out, over a winter it may take a bit longer.

A comment about solar is eventually you will almost forget its there except when you get the power bill. About the only time I check it is when I happen to be nearby and usually I just scan for the correct LEDs blinking.

NH has SRECs but the utility got the state to set them so low that its not worth selling them.


----------



## jebatty

My first frustration. I tried to put an ethernet jack and plug on the ends of the buried ethernet cable without success in getting communication. I read about some difficulty (maybe lack of skill and experience) in getting the pin-outs right and in getting solid connections, but was hoping I would luck out on my first attempt. Will try again today.


----------



## semipro

Make sure to maintain the twist on each twisted pair as close to the plug as possible. Its the twist in each pair and the fact that the twist rate varies between pairs that allows reliable communication.  

You're not trying to go more than 100m are you?  Ethernet is limited to 100m without additional electronic hardware.


----------



## btuser

jebatty said:


> My first frustration. I tried to put an ethernet jack and plug on the ends of the buried ethernet cable without success in getting communication. I read about some difficulty (maybe lack of skill and experience) in getting the pin-outs right and in getting solid connections, but was hoping I would luck out on my first attempt. Will try again today.



If using punch down blocks make sure the ends are cut flush so they don't ground.  If using rj-45 crimp-on connectors once the wires are nice and flat in the right order use  a sharp pair of scissors/shears to cut to length.  Don't mash them with linesman's pliers or the like, the ends of the wires need to be round in order to slide all the way up the connector and if out of sorts they will bunch up and cross your pairs.


----------



## jebatty

Thanks for the suggestions. I reverse wired a plug, corrected that, and the network connected. Since the power company has not OK'd yet, I could only run the panels for "testing purposes." One of the 26 panels was not acquired by the Aurora, and the installer will have to check that out. At noon today, quite clear but some haze, 25 panels were producing 4.7kw. I will be touch with the installer.


----------



## jebatty

Power company approved the install on Monday afternoon (today is Friday) and the system is on-line. The installer missed a connection on the one panel, fixed that. Network is working great. Unfortunately, intense cloud cover and rain since, hoping for sum sun over the weekend. Even with the heavy cloud cover production during mid-day is around 10% of rated output.


----------



## TommyTally

Wow, that is impressive. I'm green with envy over here.


----------



## Where2

Yes, you will find cloudy days depressing for yet another reason now... Even from my cubicle in the cube farm, I can tell when it's a cloudy day outside without being able to see a window. Although the geek in me finds it curious how the variability in cloud cover changes my A/C run time. I get the cloud cover data from my PV graph, and my A/C run time from my Nest thermostat.


----------



## Vic99

As you know, production will be low in the autumn. However, when the snow comes, the cold temps and the albedo effect will give you a slight bump.  Your numbers over a day or a week won't surpass autumn numbers, but it's pretty cool to see max output in January for an hour or so.

After being used to all that, April's production will be mind blowing.


----------



## maple1

OK, I have to ask - how much does a system like this cost, ballpark like? I have had this idea in the back of my head for years but it never moved past the 'costs too much forget about it' stage.


----------



## jebatty

> it's pretty cool to see max output in January for an hour or so.


I got a taste of what that might be like yesterday, very cloudy in the morning, but then the sun broke through in the afternoon. Cloudy production was around 700 watts, sun production at 3pm was 2100 watts data logged, and I saw a real time peak of 2800 watts.

My cost is right about $4.50/watt before tax credit. My costs are somewhat high because the system is ground mount with very sturdy racking, much more substantial than some other racking I've seen. Also, because of the nature of the soils 4 - 2 foot diameter concrete footings at 6 feet deep were placed. Then, the array is about 280 feet from my house, and all cabling is underground, including boring under the public road, and adding an ethernet underground cable as well. Our power company has some significant requirements that the electrician said also added to the cost. Finally, all work was done by the electrical contractor. The final work is very professional looking, neat, clean and orderly.


----------



## Vic99

Do your aurora microinverters clip?  Mine clip at 225 W, although I've seen 2 go to 226.  Also, realistically its rare to get there with my 255 watt panels.  My set up is roof mounted with one array At 28 degrees, the other at 56 degrees.


----------



## Bad Wolf

This is all new to me. The system is rated at 6.5kw but you're only getting 2.8kw?
How much will you get in tax credits and rebates?
What were you expecting to get out of it over the course of a year?
I'd like to incorporate solar in my next home so I'm boning up on it now.


----------



## jebatty

> Do your aurora microinverters clip?


Haven't been around to know whether or not they clip. I will look for that the next time I am present during high sun. A little over 2 hours of full sun today, but some production from 8:30am to 5:30pm, 23kwh total, and I was absent most of the day. Top average production was 5376 watts; production over 5000 watts for 2:15 hours. The low sun angle is taking its toll, clouds moved in during the afternoon, and the sun angle will continue to drop until the winter solstice. I'm heading into the worst time of the year for solar production, plus Nov and Dec typically are quite cloudy in our area, sun returning in January.



> The system is rated at 6.5kw but you're only getting 2.8kw?
> How much will you get in tax credits and rebates?
> What were you expecting to get out of it over the course of a year?


I don't expect to see rated production until mid-spring through mid-summer when the sun is high in the sky, but I'm new at this, so every day is a learning experience. I get the 30% federal tax credit, no rebates in MN available to me.
Estimated average production over a year is 715kwh per month.


----------



## Where2

Vic99 said:


> After being used to all that, April's production will be mind blowing.



Yes, I've slowly watched production wane since my system went online in August. 23.7kWh was a my best day in August, 22.5kWh in September, 21.75kWh in October. There's definitely a trend there... March and April were curious to watch on other people's Enphase systems in my area. I literally saw production graphs with flat tops from the SolarWorld 240W panels just down the canal from me about a mile. For those just beginning to look into PV systems, one thing I found helpful was to watch production numbers from systems within ~50 miles of me listed as "Enphase Public Systems". It's much easier to determine how large a system you may need when you can watch actual production numbers from a PV system near you. 

Like Jebatty, I'll only receive the 30% federal tax credit. The only incentives the "Sunshine State" offered me was no sales tax on PV equipment. That only helped with the big ticket parts because HD/Lowes managers look at you crosseyed when you tell them they shouldn't be charging you sales tax on a 250' coil of 10/3 UF (wire) and a 100A Square-D panel simply because you are using it in a PV setup, even though it is clearly sales tax exempt by state statute when used for this purpose!


----------



## jebatty

> The only incentives the "Sunshine State" offered me was no sales tax on PV equipment.


Forgot ... no sales tax in MN too. There is a form to fill out when buying things for the solar system that you give to the seller to justify no sales tax. Since 99% of my system was sold to me and installed by the designer and contractor, sales tax was not an issue.

My wife was gone yesterday visiting grandchildren, just me at home and I was out most of the day as well, so electric usage was down from normal, but never-the-less, sweeeet: production was 23kwh; total usage was 9kwh, of which 5kwh bought from the grid and 4kwh provided by solar; and solar sold back to the grid 19kwh.


----------



## peakbagger

Some general answers. Many folks get confused between W and Wh. W is the equivalent of mph, you are driving 70 mph, your solar panels are rated at 6600 W when illuminated with a specific light source. If you drive or run the panels for one hour you have gone 70 miles or have generated 6600 W for one hour (thus Wh) if the sun intensity is the same as the standard test condition (it rarely is). If the panels are tilted or the sun is at an angle to the panel you also have to do some trig. When you buy power you are buying kWhrs (Whrs divided by 1000). The daily output of a panel is for 24 hours and panels dont run at night plus the sun is rarely optimal and some days it is cloudy so the daily output varies. Thus a 6600 kW array could end up producing 2800 kWh. 

In order to estimate the average output for a particular place, the government long ago looked at sites all over the US and took long term data on how much sunlight is available on a yearly basis and that data is incorporated in some free sizing programs. The simplest on is PVWATTS. Plug in your location, panel info, angle of tilt and a few other items and it will calculate a yearly and monthly output. 

Cost for roof mounts which is the simplest way to do an install if you have a flat roof is around $3 to $4 a watt installed. Ideally you want the roof angle to be roughly your latitude. If your roof is complicated with lots of dormers and vent pipes or chimneys or at the wrong angle to the sun then you may want a pole mount. It costs more up front. A pole (or ground) mount can be slightly more efficient than a roof mount as it runs cooler and the tilt angle can be adjusted seasonally which increases the average output.

If you want to be off the grid, the panels are the same but the wiring and equipment used is different. The fed rebate only applies to grid connected units. Some folks install a hybrid grid tied system that has battery backup and get the 30% rebate. Cost wise a rule of thumb is add at least 30% to the system cost for a hydrid system so the out of pocket cost is higher. I am not aware of any leasing companies that will support hybrid systems.  

 A truly off grid system is generally 4 to 6 times the cost for grid power kWh. The initial cost is possibly 3 to 4 times more expensive with no rebates. Unfortunately for year round use the solar resource is lowest in winter when most folks want the most power. Usually off grid systems are designed for two to three days with no sun and then its generator time to recharge the batteries.

Proper deep cycle batteries properly treated may last 10 to 12 years and have to be replaced at a high cost. Poorly specified or treated batteries may be scrap in 3 years. This is applicable to hybrid systems so having a hybrid system for "just in case" events rarely makes sense. There is recently an option by one company to have "emergency power" on a grid tied system that allows limited 120 volt power production when the sun is shining, its a fairly inexpensive option but requires a central inverter based system. Most leasing firms use microinverters as its easier to design and stock the parts in a warehouse. The cost per watt for microinverters is higher but the installation cost is lower. 

The most important thing to realize is that the technology and pricing is changing rapidly and any system installed today will be somewhat obsolete in a year. It still will pump out the power but it may be slightly less efficient or have cost a bit more than the latest and greatest. Its easy to put off the decision to install waiting for the next hyped improvement but they frequently don't pan out. Meanwhile the monthly power bills keep coming. The real driver is cost of money, with real rates on secure investments at 3% and super safe (bank or CDs) rates closer to zero, installing solar generates a long term basically guaranteed return. In new england with high power rates the payback is 5 to 7 years but local and state incentives can shift that significantly. Mass currently appear to be the best state in NE to install.


----------



## jebatty

November clouds can be really dense, along with snow. Total 3 kwh Sat-Sun, but 26 kwh on Friday. It all evens out.


----------



## Brick (ware)House

jebatty said:


> Forgot ... no sales tax in MN too. There is a form to fill out when buying things for the solar system that you give to the seller to justify no sales tax. Since 99% of my system was sold to me and installed by the designer and contractor, sales tax was not an issue.
> 
> My wife was gone yesterday visiting grandchildren, just me at home and I was out most of the day as well, so electric usage was down from normal, but never-the-less, sweeeet: production was 23kwh; total usage was 9kwh, of which 5kwh bought from the grid and 4kwh provided by solar; and solar sold back to the grid 19kwh.



Don't forget the tax benefit of the accelerated depreciation.  The solar PV equipment is classified as 5 year property.  Also, since you completed installation in 2013 you should be eligible for 50% bonus depreciation.  Basically you will be able to deduct depreciation expense of 50% of 85% (100% less 1/2 of the 30% Federal Tax Credit) of the cost of the solar property on your 2013 return.  You may want to make sure your accountant is familiar with the IRS regs for passive activity loses, proper qualification and documentation for the Investment Tax Credits, and the bonus depreciation rules.


----------



## Brick (ware)House

peakbagger said:


> This is applicable to hybrid systems so having a hybrid system for "just in case" events rarely makes sense.



Although the cost of solar PV is below grid parity with incentives in many places, it is still extremely difficult to cost effectively design a system to provide back up power when the grid is down.

In addition, payback calculations need to take into consideration the practical implications of each utility's net metering rules.  Be sure to review not only the letter of the law in your specific jurisdiction, but the net metering billing policy of your utility.  Example:  Missouri law specifies that any overproduction (kWh) in a billing cycle be rolled forward throughout a 12 month period.  From a practical perspective, the utility companies have lobbied the public utility commission to allow for monthly settlement of overproduction at a predetermined avoided cost factor.  Thus, for overproduction in any month I receive a $.02 per kWh credit to my monthly bill instead of being able to offset kWhs in the next month at a retail rate of $.10.  This little surprise pushed my payback out a few years and there is nothing I can do about it.


----------



## jebatty

Other than the 30% tax credit, depreciation and the other tax benefits you mention apply only to business property, as best as I know. Thanks for the additional info.

In MN I get a monthly retail rate credit, and I think annually a check if I actually over-produce for the year.


----------



## jebatty

November was cloudier than normal. PVWatts predicted my system would produce 489 kwh during a "normal" November, and actual production was 356 kwh. And December so far has barely seen the sun. The October launch of the solar system has been less than spectacular, but Mission Control predicts solar stellar success.

I saw an interesting article predicting that by 2030, solar electric will be so pervasive that it will change the world with a new inexpensive energy revolution, just as cheap oil brought on the energy revolution from which we still benefit, albeit at ever increasing environmental and social costs. The quicker fossil fuels will remain fossil, the better.


----------



## woodgeek

jebatty said:


> I saw an interesting article predicting that by 2030, solar electric will be so pervasive that it will change the world with a new inexpensive energy revolution, just as cheap oil brought on the energy revolution from which we still benefit, albeit at ever increasing environmental and social costs. The quicker fossil fuels will remain fossil, the better.



link?


----------



## jebatty

I can't find it now, tried various searches when it wasn't where I thought. I'll continue trying. The article also dealt with vertical agriculture. Sorry.


----------



## jebatty

None of these are the article I read, but they seem to provide the same message.

http://utopianist.com/2011/01/the-w...ergy-by-2030-using-existing-technology-video/

http://www.treehugger.com/corporate...-our-energy-needs-from-solar-in-20-years.html

http://cleantechnica.com/2012/12/11...-effectively-99-9-of-the-time-by-2030-report/


----------



## jebatty

First issue appeared 3 days ago and was solved yesterday. The monitoring panel (CDD) which provides real-time status and output of each of the 26 panels reported a phantom panel, a 27th non-existent panel which it could not identify, along with an error code. The CDD has a local IP address and outputs via about 280' of buried ethernet to my computer. The 26 real panels were showing output, but one panel showed poor communication with the CDD. The solution was a reset of the CDD's acquisition of the panels and then reconfiguation, all of which is fairly straight forward but it took me awhile to discover the solution. 

I'm not overly surprised by the occurrence of the issue. 280' of Cat5e ethernet is close to the distance limit, plus it has been freaking cold. The CDD is installed in an exterior electrical box at the array, and it is fully subject to our typical temperature extremes, which were as low as -29F in the past week. I don't really know if it will make any difference, but I put a night light in the electrical box to add a little bit of heat.


----------



## jebatty

Yesterday was the first all day extremely clear, and cold, day so far in December. Temp never cleared 0F. Production was 20.2 kwh. Sun at noon is only 20* above the horizon right now, but soon will be climbing. Sunrise is about 7:55 am, and I get some morning shading from a stand of aspen trees. The sun first shines through the trees at about 8:30 am and the sun fully clears the trees at about 11:00 am. From that time to within 25 minutes of sunset the panels have no shading.


----------



## peakbagger

Clear cold weather is a good time to check out design compromises on systems. Many designers put panels that are over the output rating of some microinverters (I.E a 250 watt input microinverter with a 200 watt AC output. Its fine during most of the year but when its clear and cold the microinverter clips the output as the panels are putting out more power than the rating. One of my central inverters has the same issue, there are 2150 watts nameplate input on 2KW inverter. Normally not an issue but when its clear and cold, its obviously clipping the output, while one of my other arrays with more headroom on the inverter is putting out well over the panel string  rating. I have also seen on central inverters where the designer blew the low temp calculation and the inverter goes over voltage in the early AM when the sun first hits the panels on real cold day. Still nice to see the boost from the snow on the ground.


----------



## flyingcow

Good thread guys. Just starting to look and get pricing for solar now. I've got a clear southern view. Thinking about building a big overhang type of rack for installation. Right over where we park the car next to the garage.(most of the time the garage is full of stuff to actually put the van in there). Basically a type of car port with photovoltaic's on the roof.


----------



## flyingcow

How many sq/ft of panels for a 6.5 to 6.6kwh system?


----------



## peakbagger

If you are in Northern Maine, its important to have the panels capable of changing angles as the winter sun angles are radically different. Your winter angle is ideally roughly 30 degrees off vertical and even then, snow will build up. If you cant make them movable then tilt that at your latitude, 47 degrees off vertical and plan to rake them off.

 I think American Solartechnics has panels for sale, they are 245 watt and 39" by 68" so you can do the math. Do note that you will have to do some string calculations and use a combiner box or multiple inverters for such a large system. They are good but not the best efficiency panels but unless you are limited on roof area most folks shop for $per kw.

Before you do anything check with your utility and see if they offer net metering, You will overproduce in the summer and underproduce in the winter so unless they offer net metering it will have a long payback unless you have unusual summer loads


----------



## flyingcow

I've already been talking with American Solartechnics, just a quick conversation with Tom at this point. He's been in the solar business before it was cool. I've got one of his storage tanks and his customer service has been very good. Easy to talk to. Plus I have a local electrician who has done a ton of solar and large windmills for yrs. 

I appreciate the info on tilt. Out daylight in the summer is long, but we pay for it in the winter. As time goes on we'll see how my design/plan works. 

I have a small windmill now and the power company allows net metering but only for 12 months. The windmill isn't that big so we've never produced more than we used. But i want to check with them on incentives/rebates/etc anyways.

As i use and really like my Heat Pump, electric solar is something i wouldn't mind looking at for an investment.


----------



## Vic99

I have 25 panels at 255 W each.  Gets me 6.35 kW.  Each panel weighs 40 lbs, for 1,000 lbs on the roof, plus a small amount more for racking.


----------



## jebatty

I have 26 Suniva 265 watt panels, each 65" x 39", arranged in two rows of 13 panels each. Determining the tilt angle is not necessarily one approach is best for all. My panels are tilted at at about 34* from horizontal to maximize summer production. Latitude where I live is nearly 47*N. Yes, I lose on winter production but Nov, Dec and sometimes into early Jan are very cloudy, so tilt to improve winter production is mostly a wasted effort, at least for half the winter. 

Plus, a tilt to improve winter production brings shading from distant trees and buildings into play. Noon sun here is 20* above the horizon. I get some morning shading to about 11:00 am but I have virtually no afternoon shading. And at 20* sun at noon, about 4 hours of pretty usable production, not too much to be gained. 

Best world would be a double axis tracker, but here again ice, snow and bitter cold take their toll on mechanical systems. A large array also is not easy to manually adjust for tilt, etc. Everything may be a compromise.


----------



## peakbagger

Well if someone wants a tracker designed for cold and nasty weather this company makes one designed for VT http://www.allearthrenewables.com/products/solar/ they only sell through dealers. They appear to be very robust but pricey. They were designed to line up with VT feed in tariffs where the goal is to maximize production albeit at a higher initial cost.

I wouldn't hesitate to install one if I wanted to maximize production year round like an off gridder but with net metering the object is to go the least up front cost and leverage the installation rebates.


----------



## Vic99

"Determining the tilt angle is not necessarily one approach is best for all. My panels are tilted at at about 34* from horizontal to maximize summer production. Latitude where I live is nearly 47*N. Yes, I lose on winter production but Nov, Dec and sometimes into early Jan are very cloudy, so tilt to improve winter production is mostly a wasted effort, at least for half the winter."

I agree, fortifying your worst months production does not make sense.  Best to maximize when sun is more intense and out for longer.  Small winter gain wont be noticeable.

I, too, have Suniva panels.


----------



## peakbagger

I personally do both, two arrays are manually tilted, it takes me the total of about 15 minutes start to finish to change the angle of both of them. One is pole mount and the other is hung off the front of the house and neither would take the snow load at the summer tilt angle. The new array is on a 3.5/12 pitch roof for maximum summer production.  A lot of folks at southern latitudes forget that up north the summer sun  rises north of east  and sets near the north of west so having shallow angles extends the number of hours of daylight in the summer. 

The array hung off the house also works as a overhang to keep summer sun from heating up a room. Its shaded all day in the summer but at winter angle it lets the sun in. I didnt really plan on that advantage but it was a happy coincidence.


----------



## flyingcow

Good info. Thanks. Just figured my lat is 45.8. Like I stated before, if I do this the location is 100% unobstructed.


----------



## flyingcow

Note to self.....it's 615am and still  pitch dark out. No light on the eastern horizon.


----------



## jebatty

You're fortunate to have 100% unobstructed. Hopefully you also get some reflection off the snow on the ground. My location is as good as I could get. I will be noting the date when shading disappears. Within a few days morning sun will be earlier and shading will begin to diminish.


----------



## ewdudley

jebatty said:


> Within a few days morning sun will be earlier and shading will begin to diminish.


Depends on your definition of morning, I suppose.  In a strictly solar sense, the morning sun has been earlier relative to solar noon ever since 21 December this particular year.


----------



## jebatty

A good site for sunrise/sunset times.
http://aa.usno.navy.mil/data/docs/RS_OneYear.php


----------



## ewdudley

jebatty said:


> A good site for sunrise/sunset times.
> http://aa.usno.navy.mil/data/docs/RS_OneYear.php


Right.  So when I look up a town a hundred kilometers to the east of me it says the sun rises a six minutes or so earlier there.  Does that mean they get more sunlight?  Of course not.  The elevation of the sun at solar noon, and therefore the time from sunrise to sunset, determines the maximum amount of sunlight available in a solar day.  In the northern hemisphere the time from sunrise to sunset has been increasing since 21 December of this year.


----------



## mr.fixit

This is another sun position calculator that is kinda cool,  http://suncalc.net/#/51.508,-0.125,2/2013.12.29/20:12


----------



## Brick (ware)House

flyingcow said:


> Good thread guys. Just starting to look and get pricing for solar now. I've got a clear southern view. Thinking about building a big overhang type of rack for installation. Right over where we park the car next to the garage.(most of the time the garage is full of stuff to actually put the van in there). Basically a type of car port with photovoltaic's on the roof.



Search the web and you should find design ideas from the many prefab carport arrays currently being manufactured.  Be aware that even modules that are racked extremely close together will allow rain and water to run through.  They will keep the snow off and provide shade but the snow melt and rain will penetrate unless the racking system is designed specifically to shed all the water to the edges.


----------



## Brick (ware)House

flyingcow said:


> How many sq/ft of panels for a 6.5 to 6.6kwh system?



Depends on the peak output of the modules.  My ~29 kW system is about 2,000 sq. ft. using 305 W modules.  There are two standard sizes of modules, 60 cell and 72 cell, with multiple peak output ratings within each size.


----------



## DBoon

When I priced out my solar array, I found pretty quickly that a tiltable rack added a lot of expense and that it was cheaper to just add more panels on a fixed rack.


----------



## Brick (ware)House

DBoon said:


> When I priced out my solar array, I found pretty quickly that a tiltable rack added a lot of expense and that it was cheaper to just add more panels on a fixed rack.



That's all most always the case.  My panels are racked at about 10 degrees instead of the optimal 35 degree angle for my location.  The result is approximately a 7% reduction in annual output (around $280 worth of electrons).  A high angle was structurally impossible and a variable tilt or tracking system couldn't begin to provide the increased output necessary to amortize the additional cost.


----------



## Redbarn

As a solar wannabe, this is a most interesting thread.
Thanks for sharing your experiences.


----------



## Brick (ware)House

Redbarn said:


> As a solar wannabe, this is a most interesting thread.
> Thanks for sharing your experiences.



Redbarn -  Let me know if you have any specific questions and I will do my best to answer.  The little project seen in the top of my avatar taught me many lessons!  I haven't been out there since high school but I love your part of the country.


----------



## Redbarn

Brick (ware)House said:


> Redbarn -  Let me know if you have any specific questions and I will do my best to answer.  The little project seen in the top of my avatar taught me many lessons!  I haven't been out there since high school but I love your part of the country.


Thanks for the offer.
I'm not ready for our solar system yet but I find reading about the experiences of people who have done it to be particularly interesting.


----------



## jebatty

Clear sky and -6F cold, and at 1:00 pm panels are producing 5.6kw or 81% of rated output, and that is with the sun at a little over 20* above the horizon. No comment regarding the very cloudy days and snow covered panels. Uggh.


----------



## woodgeek

Ok, with your 56° tilt and 20° sun, the sun is 36° off perpendicular of the panels.  Cosine(36°) = 0.809, versus your 81%.  Sounds like you are making your rating, and the cold is offsetting any (small) degradation you have had to date.


----------



## jebatty

Thanks! Need to brush up on trig.


----------



## jebatty

This is the kind of info I've been collecting as I learn the performance of the array.


----------



## peakbagger

You will not believe me, but eventually 95% of the folks with solar start to ignore the system. In the short term its interesting stuff but eventually it get to the point where you hardly ever look at it. That's the way it should be, just another appliance.


----------



## jebatty

I do believe you, but this early high level of interest is to help me understand how it works, things to watch out for, and quickly solve any problems that arise. One thing I wanted to pay close attention to was the kwh being sold back to the utility to make sure the system numbers matched what the utility was giving me credit for. So far the numbers match. 

The system has shut itself down and would not restart without a power off and on reboot on four occasions so far. As best as I can tell, this happened at extremely cold temperatures (below -20F) and also snow covered panels. Those two factors may have been coincidence, I don't know. This morning it was -29F and I cleaned snow off the panels before the sun had cleared the trees which shade the early morning production, and as soon as the panels picked up the sun they were active and the system did not shut down. So, I still don't know exactly why the shutdowns before.

The system monitors itself and supplies lots of data, if I want it, as well as maintaining daily, weekly, monthly and annual reports. Sooner or later that will be enough for me.


----------



## jebatty

System went active Oct 28, and now Nov and Dec have ended and I'm estimating that the morning shading with low sun angles has reduced production about 20-25% over optimal, and January likely will be the same. I don't have info to determine whether these months were cloudier than average. Assuming average irradiance, my production for Nov was 65% and for Dec was 60% of predicted. But even at these levels the panels since going active have been producing close to 100% of our general service electric usage. Soon they will cut into electric for dhw and supplemental electric heat usage.


----------



## peakbagger

In the northeast November and December are the worst months for sun. Usually January and February may be cold but more sunny days.


----------



## begreen

With longer days starting and a higher sun angle we are starting to get some production again. Just a few hours at this time of year, but that's better than none. It will be picking up rapidly now as long as it's sunny outside.


----------



## jebatty

My awe will dissipate as the first year of solar runs its course. Tue and Wed were two successive clear days, panels produced 26kwh each day, and peak output was 6kwh for about an hour on Wed, that's 88% of rated output.


----------



## Former Farmer

I have a 10.2kw system mounted on the roof of my shed.  18* pitch.  This will give you an idea what to expect as the days start to get longer.

The system is comprised of 40 255w Solarworld panels with Solaredge power optimizers and Solaredge inverters.  System went online in Nov. 2011.


----------



## jebatty

Thanks. If I read the graph right, Dec '11, '12 and '13 were respectively about 450, 330, and 440kwh? My Dec production was 268kwh.


----------



## woodgeek

So, we can expect your peak power production to increase to the 100% rating as the sun gets closer to being perpendicular on the panels (spring and fall), and your total daily production to follow hours of daylight.


----------



## Former Farmer

jebatty said:


> If I read the graph right, Dec '11, '12 and '13 were respectively about 450, 330, and 440kwh?



443, 300, 435.  

Your 268kw divided by your 6.5k system equals 41.23kw per 1k of system.  My 440kw divided by my 10.2k equals 43.13kw per 1k of system.  So our systems are pretty similar to each other.

Right now I have 4 of the panels are not producing because of snow cover.  It isn't enough of a loss for me to spend over an hour to clean them off.  I will wait until more are covered with snow or the sun melts them off.  This is one advantage of using micro inverters or power optimizers versus just a central inverter.


----------



## peakbagger

I had some high winds today that cleaned off my shallow roof panels so I got some production back, they are shallow so the angle is bad in winter but on a cold day they still contribute when they aren't covered with snow. My pole mount panels angled for winter maxed out their inverter for a few hours due to cold clear skies and snow reflection and my oldest wall mount system was also humming along quite well today. Now all I need are some longer days.

As I have varying vintage systems installed to three NEC code revisions, not everything is optimally sized. I am really tempted to make an inverter swap so that my pole mount has more head room in winter. Inverter capacity means far less in the summer as the temperature derate usually limits peak production but obviously there are far more hours of daylight.


----------



## jebatty

Yesterday solar production beginning with Oct 28 passed the 1000 kwh mark. Oct 28-Jan 30 = 94 days, total solar was 1020 kwh, General service electric meter for same time period was 1008 kwh, so solar met 100% of general service electric use. Nov-Dec was at about 60-65% of predicted irradiance, and Jan is at about 80%, so on year to year average solar should do better than it has done this period. Next goal will be for solar to also meet 100% of dhw usage, which averages around 100 kwh/month.


----------



## peakbagger

Once you get over 1000 kW, you are generating Megawatt hours (far more impressive). I always have thought there should be club that awards a "first MW" award like the first dollar award that chamber of commerce's gve out. Good luck on getting to 10!


----------



## jebatty

I'm bending the rules a bit because this is a partial re-post of most of the same info in the thread $9 heating and electric bill combined. But it belongs here, so unless I get canned ....

I expected a longer payback than at the $4/watt install standard because I had to do a ground mount, underground wiring 280 feet to my house, etc., also I used micro-inverters rather than a DC string inverter, and my install cost came to $4.59/watt. All work was contracted, not done by myself. The cost is a real number. I get a 30% federal tax credit which reduces my cost to $22,400, or $3.21/watt.

Attached is a chart showing my payback at year 20, far less than the life expectancy of the panels. And most interesting, after 20 years the payback far exceeds a standard competitive investment. At year 30 the solar system is $16,000 ahead in present value dollar over a CD investment.

Here are the assumptions for the calculations based on historical 20 year averages:
Average 5-year CD interest rate the last 20 years = 3.75%
Average inflation (discount) rate the last 20 years = 3.5%
Federal tax rate, current, not expected to change = 25%
Annual panel derate/yr = 0.5%
Current kwh rate ($0.108 x 1.06875 sales tax) = $0.115
Average annual energy cost increase the last 20 years = 5%


----------



## Former Farmer

Are you or can you get time of use rates?  With the solar producing during peak hours, this can really change things.  

My utility pays back at the same rate that I am charged.  For on-peak hours the rate is .2725 and for off-peak hours the rate is .0525.  I have been averaging over $1100 per year payback from the utility for the last two years even though I use just about as much as I generate.  I generate over 13MWh per year and consume 12MWh per year.


----------



## jebatty

I have general service rate at $0.108/kwh and dual fuel rate at $0.053, sales tax on these at 6.875%, plus $14.00/mo base charge. Utility buy-back is at $0.108 rate for all buy-back. During Jan I had general service meter usage of 281 kwh, direct solar usage was 103 kwh, and 318 kwh of utility buy-back. I also had 1750 kwh of dual fuel meter usage, about 100 kwh of which was dhw and the balance supplemental electric heat. The extra cold weather this season, and still continuing, is boosting supplemental electric heat quite a bit over that of recent years.


----------



## DBoon

jebatty said:


> Attached is a chart showing my payback at year 20, far less than the life expectancy of the panels. And most interesting, after 20 years the payback far exceeds a standard competitive investment.


Hi jebatty, nice spreadsheet.  Another way to look at this is to calculate over the 30 year life of the solar PV installation what guaranteed rate of return would have to be earned to equal the investment return of the solar PV installation.


----------



## jebatty

I deluded myself into thinking that we could make it on 9000kwh/year estimated annual production. Our general usage + hot water will be about 350-400 kwh/month, which I think is quite low. We maybe can reduce usage somewhat more on our general service, but that won't be significant or make up what would be needed to cover supplemental heat. We used about 1675 kwh in each of Dec and Jan, and with the continuing very cold weather in February (-teens at night), Feb will be high also, then still some heat in Mar and probably a little in April. Total electric would be in the range of maybe 5-6000 kwh @ $0.06/kwh or $360/yr, subject to ongoing rate increases. Interestingly, that 6000 kwh translates to the btu energy in about 1-2 cords of aspen stove wood.

Have to consider a Plan B. Long have thought about adding some solar hot air. We have an area on the front of our house that faces SW, roughly 3' x 25', that could be fitted with a hot air collector to help warm the basement. Hot air should be the more simple and probably less expensive than hot water. Time to cost it out and see if it is in the range of reason. Plan B would involve minimal ongoing maintenance.

Or Plan C. Not as preferable, but also will consider an upgrade to our wood stove heat and a larger stove, probably a fireplace insert with blower (we have a large fireplace which we use little), that has capacity to move enough heat to the basement to maintain a 50F temperature. Time to cost this out also to see how it might work. Plan C means more effort in wood c/s/s, but the wood comes from our land and has no out-of-pocket cost.


----------



## maple1

Jim - what about a Plan C (1) - run some lines to your house & heat it & DHW with your boiler & storage? Or maybe you don't have a heat distribution system in your house?


----------



## jebatty

The Tarm is in my shop, about 250' from the house and across a township road. Quite expensive to run underground piping, plus no hydronic heat distribution system in house. Plus, wife loves the wood stove and the radiant heat it gives off. Great start to the day to sit in front of the stove with a cup of fresh brewed coffee.


----------



## jebatty

Did some simple math to calculate how much production loss was caused by some tree shading. I have morning shading from trees. Yesterday Feb 14 the sky remained clear dawn to dusk, although the satellite photo showed some haze. The sun zenith was 30*. My system logs output every 15 minutes. I simply added up the log points from first production to 12:30pm (approx solar noon) and then from 12:30 to last production: in simple terms the difference would be caused by shading. I assumed that insolation was the same in the morning as the afternoon, but of course it might not have been. The afternoon produced 3.4kwh more than the morning, so if no shading morning would have been 3.4kw higher. For yesterday that meant that production of 37.6kwh could have been 41kwh. Or stated differently production was 92% of maximum.

I did the same calculation for Jan 27, sun zenith 24.6*, production was 65% of maximum. Actual production 29.5kwh, could have been 45.4kwh.

Another interesting figure. My Jan 2014 production was 80% of predicted January, so the shading calculation likely means that if no shading my production would have exceeded estimated. Predicted Jan was 482kw, actual was 427kwh, could have been 561kwh, or 117% of predicted.

Of course other factors could impact these calculations. In general, fwiw, through observation it appears that the sky on a clear winter day is more clear in the PM than in the AM.


----------



## jebatty

Continuing with the math. The production records for Nov-Dec plus detail on the few days that appeared to be clear dawn to dusk indicate that a pretty good estimate for the impact of morning shading on daily production is 25% less than if no shading. Fortunately these also are the lowest production months. Based on estimated yearly production of 9000 kwh, the cumulative impact of the shading comes to about 4% reduction in estimated annual output -- not very much, but every kwh still counts. 

By March 1 sun zenith will cross the 35* point and impact of shading should be very low to nothing until mid to late October.

With the snow we get each winter, and this winter has been more snow than some others, the ground mount has been a blessing. A floor broom with an extended handle makes short work of clearing the snow off the panels. I don't even want to think how I could clear panels if they had been roof mounted.


----------



## peakbagger

I did this post on another form which may be of interest

_Thump goes the snow

My new array is mounted on a low pitch roof (for new england) 2nd floor roof about 35 degrees from horizontal. I have had snow cover on the panels on an off all winter but not significant. We have been having snow on and off for the last 10 days although luckily have been on the fringe of storms so I would estimate about 16" of snow cover compacted down 10" on the panels . Today we had a fast warm up and while on the phone with a client I heard and felt a rumble above me. Out of the corner of my eye I caught the snow sliding off the panels in one sheet ending with one big "Thump". The snow sort of arced off the roof and fell several feet away from the house which was fortunate as I have a set of wall mounted panels immediately below the roof array that are angled outwards. There was no trace of any snow landing on the lower edge of the wall mounted panels but it was close. I sure didnt engineer it that way but had hoped that if it did happen that that would be the result. My wall mounts are adjustable for angle but given this experience I think I might hold off a bit before cranking them out to their spring angle which would present more of a target. The rest of the roof is asphalt so snow never slides off, the only way it comes down is with a snow rake or melts.

I realize I could rig some snow hooks but I think I am just going to make sure I snowblow a path in front of the house away from the fall zone. Beats hurricanes and tornados but every climate has its solar challenges. 
	

	
	
		
		

		
		
	


	




Meanwhile the freshly uncovered panels are cranking out the watts until the next storm
_
The array on the roof is my "bonus "array intended for non snow season, my wall mount and pole mount arrays dont have the snow build up issues as they are at 30 degrees from vertical and shed snow quickly.


----------



## jebatty

On my system install cost, a 4% reduction in production results in one additional year to payback.


----------



## jebatty

Time to declare the array shading free. Sun zenith 33.84* at 12:33. Attached is yesterday's (Feb 23) production chart. Near perfect bell curve, very clear day, but some still some haze as shown by the satellite photo. The little blip in late morning is the last tall tree that fights the sun and the last gasp of shade. Also attached is the production log. Microinverters are rated at 6500 watts and 6760 maximum output power. From 11:30 - 13:45 the array was in the rated/maximum range.


----------



## jebatty

February was a great month. After 4 of the lowest production months, the system payback already is about equaling the one year return on a CD. Solar pays.


----------



## jebatty

Yesterday, Mar 8, my system reached the 2 megawatt production benchmark. Jan 29 was the 1 megawatt point. March so far has been electrifying, with 273 kwh in the first 8 days. Three of those days each had 47 kwh, the single day high point so far. Cold weather and clear skies mean lots of electricity.

The first 8 days of March exceeded in production the entire month of December.


----------



## jebatty

I just received my electric bill for the period of Feb 8 to Mar 8. The bill was -$41.00! I think I'm going to enjoy a solar electric system that meets all of my electricity needs and which results in the electric company paying me rather than the other way around.


----------



## jebatty

March was a very good month, exceeding estimated production by 117%, coincidentally the same as February. The first two days of April were good, but now we're headed for a couple days of snowy weather.


----------



## jebatty

... and the bill arrived for Mar 8 - Apr 8: bill was -$104.00, total accumulated credit is now $145.00.


----------



## flyingcow

Appreciate the updates.


----------



## AK13

I am curious how you are liking your Sunvia panels and how you decided to go with that brand. I just got a quote for  24 panel system and the cost to go with Sunvia is about a $1200 premium compared to the Canadian solar brand panels (after 30% tax credit).


----------



## Vic99

After a year and a half, no problems with the Suniva panels.  My wife and I like the black color with very thin white lines.

First I looked at the tested rating for the panels here:  http://www.gosolarcalifornia.ca.gov/equipment/pv_modules.php   Essentially it compares panels watt rating with what they actually produced in the test.  So for example if a panel is rated for 240 Watts and it tests at 211 Watts, that's 87.9% of output of what it was rated for during the test.

If you want to meet 100% of your electricity needs, try to size bigger than you need (see below).  Look at the last two years of energy bills.

Higher number is better for obvious reason, but also UV light will degrade panels over time.  I'm told a panel typically loses around 0.5 to 1.0% of its output Watts each year as the panel clouds up a bit.  It eventually reaches a saturation point and does not cloud any more.  Most manufacturers will "guarantee" a panel is producing at least 80% of it original rating after 25 years.  Who knows if they will still be in business, etc.  Thus a higher starting number is better.

I have enphase M215 microinverters which clip at 225 W, but realistically, I only reach that less than 1% of the time anyway.

I buy American where I can.  I'm not a zealot about it, but it factors in strongly.  Perhaps some of Suniva panels manufacturing is outside of U.S., but seems they make them in Georgia.  Your quote looks like an extra 50 bucks a panel.  For me that was not an issue when I look a break even point of around 7-8 years.  State of MA gave me 1k, feds gave 30%, I'm in for 10 years of SRECs.  I got a Chevy Volt the next year (another 7.5K rebate, thus paid only 24.5K for it new . . . I hardly buy any gas).  Good long term investments that will probably pay me more than I could place elsewhere, not being in the investment field.

Canadian Solar are made in China.

I'd do it the same all over again, with maybe 3 more panels ( I got 25 rated for 255W).  If you have any other questions post here or PM me.  I'll talk your ear off, if you like.


----------



## CaptSpiff

Vic99 said:


> After a year and a half, no problems with the Suniva panels.  My wife and I like the black color with very thin white lines.
> 
> <snip>
> 
> I'd do it the same all over again, with maybe 3 more panels ( I got 25 rated for 255W).  If you have any other questions post here or PM me.  I'll talk your ear off, if you like.



Please don't go "private chat", unless what you're discussing is private. This is where I come to learn from others.

If i'm not learning from this group, I'll have to go back to "making it all up".


----------



## CombatChris

This thread has been super useful and inspiring to me also. Keep it all public, man! This is good information. I for sure am thinking about a setup like this for the future-homestead. With data like this, I'm sure it's a lot easier to get a loan to cover the installation cost.


----------



## AK13

I'm still trying to decide what panels to go with. I might head to the showroom today to check out both models. Its tough for me to justify the extra $ on the buy american aspect alone. I also like to buy American, but I like the idea of keeping my total out of pocket to $10k and its tough to spend more money and get a worse payback. I wish there was just a little more benefit to the Suniva like a jump in capacity to 275 watts each instead of just going from 255 to 260. 

I'd like a crystal ball to tell me which company will be around in 20 years to honor the warranty. My coworker spent a lot extra to buy american panels a few years ago and then the company promptly went bankrupt. So much for that warranty.


----------



## jebatty

April ended well, just slightly below estimated April production.


----------



## CombatChris

Maybe I missed it, but how do you come up with the different expected numbers for each month? Is there a calculator which can determine the angle of the sun and it's daylight hours based on a location? I just noticed you being in MN, I wonder how much different the setup's output would be down here in NC.


----------



## jebatty

I had many of the same kinds of questions that AK13 has, but now that my system is in and producing, I am very pleased with what I have. In some ways making a choice is somewhat like choosing what computer to buy in past years, because as soon as a person would buy a computer a newer, faster, and less expensive computer would arrive on the scene. My point is, solar pays, make the choice and move forward. Every decision is subject to buyer remorse or 2nd guessing. Alternatively, hire a consultant you trust to design and spec the system, a contractor you trust to do a turn-key installation, and spend your time doing other things until the system is operating, and then sit back and reap the rewards.

My Suniva panels are rated at 265 watts, and the Aurora micro-inverters are rated at 250 watts continuous, 260 watts maximum, and maximum usable DC of 265 watts. So far I have had periods up to 4 hours when the panels are producing maximum, with a peak of 268 watts observed output from the micro-inverters. That peak output will not be sustained for long, and the micros will clip back to 255-260 watts/panel. 

While April production overall was very good, I observed higher output, although over shorter periods, in March than in April. March had more clear skies, was colder, and April had good skies but with variable clouds moving in and out. April ended with six very cloudy days as the big storm system moved through the US. Up to that cloudy period, average output was in the 40-45kwh/day range. And May is starting out quite cloudy.


----------



## AK13

jebatty said:


> I had many of the same kinds of questions that AK13 has, but now that my system is in and producing, I am very pleased with what I have. In some ways making a choice is somewhat like choosing what computer to buy in past years, because as soon as a person would buy a computer a newer, faster, and less expensive computer would arrive on the scene. My point is, solar pays, make the choice and move forward. Every decision is subject to buyer remorse or 2nd guessing. Alternatively, hire a consultant you trust to design and spec the system, a contractor you trust to do a turn-key installation, and spend your time doing other things until the system is operating, and then sit back and reap the rewards.



Good advice! I am essentially doing just that, except that the turn-key contractor gave me 2 options. I just need to take a loooong deep breath, pick one panel or the other and write the check! 

Thanks for keeping this thread up to date. It is interesting that your projected energy production is so much better than for my system. My 6.24 kW Sunvia system is only projected to make 6,498 kwh. I do have a little bit of winter shading when the sun is low. But with your pole mount system you are probably 100% shade free and tilted/pointed in the optimal position.


----------



## jebatty

You can check PVWatts to get an estimate of production for your location, or at least for a location close to you. PVWatts has lots of other info available also.
http://www.nrel.gov/rredc/
I wish I was 100% shade free. On Dec 21 the sun at solar noon is 19* above the horizon, which results in some shading from quite distant trees. I tracked production carefully from install on Oct 28 to current date, and my estimate is that the shading, while "significant" as related to estimated monthly production for Nov-Jan, likely only amounts to 4% of estimated total annual production, or about 400 kwh, or about $11.50 in the cost of purchased electricity at current rates. My site is the best I could do in my location, and is very good.


----------



## Where2

jebatty said:


> My site is the best I could do in my location, and is very good.



Much like my 4.4kW array on my second floor roof. I couldn't change the direction the house faced, or where the neighbors trees were located. I went with the cheapest panels I could find at the time, from a company that was already known to be bankrupt (Evergreen). I knew going in that my panels had no warranty. I've generated enough energy from them to cover more than 13% of the cost of the entire pallet panels, in just nine and a half months! At my current electric rates, if my panels last 5.54 years, they will have completely paid for themselves (not including any of the balance of system parts, just the pallet of panels).


----------



## peakbagger

Two of my arrays are set up with panels from bankrupt companies. I knew they had no warranty going into it but both suppliers did offer a replacement for DOA  panels. I did a large order for one of the arrays that was shared with someone else and I picked up one spare mostly in case of future mechanical damage. On the second set I didn't buy a spare and will take my chance.

Both brands were panels built for the German market and were known brands. I had substantial savings on both sets compared to companies still in business.. The price disparities between non warranty and warranty panels have dropped so I may not have made the same decision the next time around. I would stay away from some of the orphan technologies like the flexible panels or the Solyndras (optimists who picked them up auction still have pallets of them for sale on Ebay). I have seen a couple of reports on failed Solyndras and don't see why any one would want them.

I have subscribed to Home Power magazine for many years and reports from the field is that panels rarely fail unless physically damaged. Kyocera did have a bad run of panels at one point and did replace them and I expect there may have been other failures but they were definitely a minority. At $8 a watt this was a major concern but its far less when panels go for $1 a watt.


----------



## begreen

Panels don't just die after the 20 yr or whatever warranty period. They may no longer supply full output, but should be producing power steadily for years afterward, long after they have paid for themselves.


----------



## jebatty

... and the bill arrived for Apr 8 - May 8: bill was -$86.00, total accumulated credit is now $231.00. On May 12 the system crossed the 4MW production point.


----------



## CombatChris

jebatty said:


> ... and the bill arrived for Apr 8 - May 8: bill was -$86.00, total accumulated credit is now $231.00. On May 12 the system crossed the 4MW production point.



What's your historical billing data for your electricity? If you've got something like 3 years of usage backlogged you really could calculate savings as well as just credit you're earning from the utility.


----------



## jebatty

Annual usage was approximately 12,000 kwh before install of the solar. Since the install we also have added LED lighting and further increased our attention to shutting things off when not being used. Current rate is $0.115/kwh for about 5-6000 kwh and about $0.065 for about 6000 kwh, plus $14.00 month base charge.


----------



## jebatty

I think I have tracked my system well enough for the data to show what I was told: highest peak output occurs during cold months. During clear sky conditions in March, with cold outside temperatures, output would peak at about 6.85 kwh and would stay at that output for a couple of hours. Now during clear sky conditions and outside temp in the 70's, peak output is just over 6.0 kwh and holds at that output only for about an hour. The explanation I have heard is that heat is the enemy of electricity (resistance rises and output falls); also that summer skies which look clear actually have less solar insolation per unit of time than winter skies due to dust and humidity in the atmosphere.

Today (May 22) was nearly clear all day, except for early morning. Total output for the day was 46 kwh, starting at 5:30 am and ending at 7:30 pm CST. On March 1, 2013 output started at 7:30 am and ended at 5:30 pm CST, and total output on March 1 was 47 kwh, although the period of production was 4 hours shorter on Mar 1 vs May 22.

It may be that my maximum daily output is about 47 kwh. In another month will be the summer solstice, the longest day of the year. Will wait and see if this production scenario remains accurate.


----------



## denjohn

Thanks jebatty..............It would seem that ground rack systems w open backsides would be cooler and more effective than roof mount.
Has anyone seen any comparative studies?


----------



## peakbagger

I haven't seen real world studies but many string calculators have temperature inputs that vary if its a roof mount versus a pole mount. There is no significant benefit in cool weather, its mostly a los of panel when hot. The specific rack detail on the roof will make a big difference as the roof pitch array configuration, stand off height and if the panels have edge flashing all impact the air flow under the panels and the roof ultimate temp of the panel. Most ground mounts are fixed, while poles mounts generally can be at least be manually tracked on horizontal axis. It is quite noticeable the additional hours of generation I get in the summer when my pole mount is at its summer angle. I pick up a couple hours in the AM and PM especially as the summer solstice nears.


----------



## jebatty

The Suniva panels I have (265W) show a -0.42% in power output per degree C from maximum power at 25C. From observation, maximum power output was about 6800W on March 1 and about 6000W on May 22, a 9% decline in power, which would correlate to about a 22.5C (41F) temperature difference.

I don't know whether the spec temperature of 25C relates to panel temp or air temp, but thinking it probably is panel temp. If it is panel temp, the panels easily could be at 25C in sunny cold weather, and then of course much warmer as ambient air temp rises, and therefore the decline in power output summer vs winter.


----------



## jebatty

May was extremely cloudy. The system needed to average 35.1 kwh/day to meet the PVWatts predicted monthly production, but output at or greater than 35.1 kwh occurred on only 13 days. 4 days were below 10 kwh. Highest daily production was 46 kwh. The goal for June is 37.2 kwh/day.

I like the 2.36% ROI after only 7 months of operation -- already beats the best 5-year CD rate (2.3%) currently available, and leaves the one year rate (1.1%) far behind.


----------



## WoodNotOil

Hey Jim.  Congrats on the install!  It's nice to see real solar data from somewhere in the north.  I'm planning my install now and hope to end up at a similar size to yours in the end, but will probably start smaller and keep adding to it.  I like the PVWatts tool, gives a great baseline for planning and looks like it's pretty helpful in tracking your real numbers too.

I was wondering if you did any of the work on the install?  As with all my projects, my hope is to do as much of the install as possible and only involve an electrician to implement the actual grid-tie to satisfy the utility and my local regulations.  Partly because I love messing with stuff myself and partly to bring down cost.  The bits and pieces seem mostly plug and play.

Lastly, I am curious if you did the 30% Federal Tax credit (any state incentives where you are?) and if so, how that worked out for you.

As always, thanks for sharing your experiences!


----------



## jebatty

The only work I did myself was installing and setting up the array monitoring device. Like you, I usually do everything myself, but not this time because the ground mounts needed to be installed in a wetland which included boring holes that would fill with water, pouring the concrete, etc; also nearly 300 feet of underground wiring from the array to the house and boring under a road for the wiring; and most importantly I did not have the time. Assembling the racking and installing the panels is a 2-3 person job -- that stuff is heavy. The electrician did a great job. I do not regret having the work done by someone who has done lots of installations before.

No state incentives in MN, other than solar equipment being sales tax free and a good net metering law. Federal tax credit was great, easy on its own but I've used an accountant for my taxes for along time due to my prior and ongoing business interests.

I trust your install will go well. I have no regrets at all on this project.


----------



## peakbagger

I have self installed 3 systems. One pole mount, one wall mount and one roof mount. In all three I did everything myself with no help. With a helper they would have gone faster but as one wasn't available I worked slow and thought ahead. With regards to a roof mount, if someone is comfortable re-shingling a roof they can install solar panels. The racking is well documented and the biggest pain is locating the centers of the roof rafters to screw the mounts in. Running the conduit from the attic to the basement was time consuming and I had to cut a few handholes in the drywall in closets to get it to run the right place, I expect an electrician my not have had to cut the handholes.  I personally made sure the details were right while I am not so sure that a crew on an incentive to crank them out fast would do as good of job.

The major advantage that an installation crew has is they have gone through it a few times and know what tools they need and they have specialty tools that speed things up. Given the ever lower price of equipment, labor is a much larger percentage of project cost. I recently looked a solar quote for a friend and the labor was just about half the cost. Of course we live in rural area so the installer has to drive 2 hours one way which would be a cost that folks in more urban areas wouldn't have to pay. There are local electricians that will do installs but since they don't do it all the time their efficiency will not be much better than yours. I wasn't in a rush to do the install and did it over a few days so I did a lot of preplanning to try to save steps but some days, I spent more time going up and down the ladder then actually working on the roof.

One thing that does factor in is various states interpretations of what must be done by electricians. In NH, the only paid person that can legally touch a solar panel is an electrician from the point where it is taken out of the box to when its running. If its a DIY and the homeowner can get an electrician to sign off (like I did), its not an issue but it does raise the cost for a professional installation. In other areas, roofers can install the panels with the electricians making the final connections.  The trick that most install companies do is they make a couple of laborers electrical apprentices and push the "under direct supervision rule". There is also NABCEP certification which requires an apprenticeship period so anyone wanting to get into the solar field have to work at minimum wage until they get their hours in. 

One last important detail is buy a can of Never Seize, most of the fasteners are stainless steel and the quality may not be great, one little burr on a stainless thread can turn into galled fastener and the only way to get it apart is by breaking it or cutting it off. A dab of never seize on the threads does wonders and if you ever need to take them apart, that one extra step will be paid for. Many folks over do it and it can get messy.


----------



## Where2

peakbagger said:


> One last important detail is buy a can of Never Seize, most of the fasteners are stainless steel and the quality may not be great, one little burr on a stainless thread can turn into galled fastener and the only way to get it apart is by breaking it or cutting it off. A dab of never seize on the threads does wonders and if you ever need to take them apart, that one extra step will be paid for. Many folks over do it and it can get messy.



I was fortunate that FL allows me to wear all the hats if I'm putting a PV system on my own house. As the designer, FSEC PV system certification holder, building permit holder, installer, and end user of my system, I agree with Peakbagger's comments. The value of installing a system yourself is in your ability to handle all the fine details. I had my bottle of never seize on the roof with me. A box of disposable nitrile gloves goes a long way toward keeping the mess down when using that stuff, and keep a rag handy. My system used black anodized panel frames and rails, I paid particular attention not to get the silver anti-seize paste all over everything. I learned long ago that the metallurgical properties of cutting threads in stainless steel is what causes galling problem that Peak described. I've had to break a $4 1/2" stainless hex bolt, because I failed to use never seize on it. I'm not a big guy, and it took a 4' pipe on my 1/2" drive tools to shear that bolt after the nut bound up in both directions. (I live on a salt water canal, all my floating dock hardware is 1/2" 316 grade stainless steel fasteners). I can't afford to throw away $4 stainless bolts all day long...

When I installed my PV system, I found the local big box hardware store had stainless steel tie wraps, on clearance. I put heat shrink tubing around every stainless tie wrap to separate the stainless from the black anodized aluminum rack rails. I used these for all my trunk cable management instead of the typical wiley wire clips. Even in a hurricane, my trunk cable will not move or come unclipped. All my tie wraps are hidden under the panels, out of direct sunlight. My building inspectors quickly noticed the heat shrink wrapped stainless tie wrap detail, as well as the Hubbell Weigmann NEMA 4X hinged lid fiberglass enclosure I used as a junction box on the roof for my transition from Enphase trunk cable to 12/4 TC-ER sunlight and oil resistant cable to feed down the weather head through the roof. Instead of wire nuts, I used UL rated industrial automation DIN-Rail terminal blocks on DIN rail mounted to the non-metallic back-panel to splice my 12AWG wires inside the fiberglass enclosure. My PV combiner panel is a 100A Square-D QO series breaker panel, sized for future system expansion. I have extras of every NEC warning label in my system, if sunlight fades them in 10 years, I'll just replace them. When you have the liberty of picking every item in your system, you can use the quality you choose. I tried to design my system to be as trouble free as possible for as long as possible. The weather in South Florida is rough on things left outside 24/7. My use of the fiberglass NEMA 4X enclosure was based on experience using them at aquatic theme parks around salt water.

Having purchased a high end "stud finder" a model suggested by my structural engineer, I fully recommend using the framing hammer thump method to locate your trusses. I had to put 204 5/16"x3" stainless lag bolts into my trusses to attach my 102 creotecc tile hook mounts to the roof structure to meet my local design criteria to withstand a 3 second gust of 170mph. Despite having tongue and groove roof decking, the framing hammer thump method proved more reliable than electronic means for locating my trusses.

My install took over a week just to get all 102 tile hooks bolted to the trusses, and to put my metal tile roof back together. Ladder up to ladder down took two months, but I only took a week off from work to get as much done as I could, so that basically covered dismantling my metal tile roof, the mounting of the tile hooks to the roof trusses, putting the roofing back on, and approximately mounting the 6 rails for two rows of panels. (yes to get the three second 170mph gust wind load rating, I have three rails supporting every panel!). After the first solid week of work, I was cut back to evenings and weekends and calendar time flies when you have only evenings and weekends to accomplish stages of the project between in-progress inspections for electrical and structural work (which can only be scheduled on weekdays). I too had to pull wire from the second story attic down to a panel on the outside of the ground floor of the house. I chose to pull the wire through the walls rather than slapping an ugly conduit on the outside of the house. I installed special nailer boards in the attic just to attach and route my pair of 10/3+gnd UF wires and 6AWG ground wire. When my inspectors saw my 220V wiring through the attic, they said no licensed electrician ever wires anything that neatly.


----------



## jebatty

I thought about doing more my my install, but concluded that it was not likely that I ever would do another, and therefore that it didn't make much sense to learn everything, a little trial and error, and have the install take a long time. Footings were poured in week one and allowed to cure for several days, and then by the end of week two the system was done, inspected by the electrical inspector, and ready for operational testing. On Monday of week three (Oct 28) the power company inspector came out, measured all parameters to comply with its grid tie requirements, the system passed and then was fully on line. 

In addition to the things mentioned above in my post above, the electrician installed a production meter, a buy back meter, changed over the domestic hot water heater to a new reduced rate meter, and did some main panel work as well. 

I admire all of you who do everything yourself. I'm not a novice at electrical work, but I just didn't want to take on a big unfamiliar project in late fall when winter soon would be blowing at door.


----------



## peakbagger

DIY is definitely something that some folks like to do and some folks dont. More importantly some folks should not try as they cut corners, or dont read and follow instruction manuals and installation instructions. My background was mostly acquired from reading Home Power cover to cover for several years. No matter what, DIY is going to take many more hours than a skilled install crew. 

Some folks have the option of participating in a energy cooperative that does solar "barnraisings". There is a small local group near me that does both SHW and PV, when a member builds a system or adds one, frequently they invite other members to assist and its a good way of getting good info on what ti takes. A large group is about an hour away http://www.plymouthenergy.org/update.html, they have a group buy for Apricus evacuated tubes so they tend to do a lot more SHW installs. SHW installs are a lot more practical as it can be done by skilled volunteers but as discussed in my prior post, PV requires electricians.


----------



## jebatty

Passed the 5MW production point on June 13. The clouds and rains of May are continuing into June. Lakes, ponds and wetlands around here are at or near the highest in water level that anyone I've talked to can remember. And the rain weather pattern continues. The last 16 days of June will have to be very sunny if the June production goal will be met.

Also interesting, and something of which I was aware, our late spring (and summer too) days frequently are clear until about 1-2pm, and then clouds roll in, and the sky again clearing in late afternoon/evening. On days like this, which are now very long, production is right around 43kwh, which is very good even with the clouds. I continue to wait for a clear day dawn to dusk, and if that happens, I think production would exceed 50 kwh for the day.


----------



## jebatty

PVWatts has added to its database a location only 45 miles from where I live as opposed to the prior closest location 100 miles away. The result is about a 7% reduction in estimated annual production and (hopefully) monthly estimates which more accurately reflect solar insolation where I live. My monthly aggregate report which in another week will include June is incorporating the new PVWatts location data estimates.


----------



## jebatty

June also was very cloudy with lots of rain. I modified my projections based on new PVWatts data. Surprisingly, June came in a hair above the average prediction.


----------



## jebatty

The 6MW point was reached on July 15. As the sun zenith now gradually falls, I'm beginning to notice that peak output is rising, again starting to reach into the 6000+ watt output range. July output likely will not reach the projected output. I don't think July so far has included one fully sunny day. Still waiting for that 50 kwh production day to materialize.


----------



## jebatty

July production was better than I expected, even though it fell a little short. There wasn't a single clear day, dawn to dusk, lots of variable clouds and haze. Based on the predicted Average, production at the 9 month mark is pretty close to having the year finish as quite "average." Very pleased with the decision to install the solar PV.


----------



## JP11

Anxious to get mine in.  12.2kw

The only spreadsheet I have going is COSTS so far.  

I plan to do a similar output spreadsheet, and use it to calculate an average yearly production, and keep a 'running total' on payback point.

Being 40 years old... I hope to have many years of 'free' power from the system.

Went by the office of the solar place to actually SEE the panels and gear.  It's all going on my barn.. so it doesn't really matter.  Inverters going high up on the wall so as to be out of the way.

Have you calculated out break-even?

JP


----------



## jebatty

A previous post in this thread shows the NPV calculation.
https://www.hearth.com/talk/threads/solar-electric-6-5-kw-system.116031/page-4#post-1654839


----------



## JP11

jebatty said:


> A previous post in this thread shows the NPV calculation.
> https://www.hearth.com/talk/threads/solar-electric-6-5-kw-system.116031/page-4#post-1654839



Thanks.  My concern is more getting into 'the black'.  I'm just curious where I cross over into using 'free' power.  I'm guessing around 10 or 11 years.  Maine just announced a 4% rate hike.  Math moving in my direction already.

I'm not that interested personally in 'opportunity cost' of what I could do with  the money.  The intangible to me is getting away from the risk of price increases of the electric market.  I like the idea of being green.  It's a plus.. but not the only factor.  I like being self sufficient.. I place a big value on that too.

We all have different motivations.

JP


----------



## jebatty

"Getting into the black" occurs for me at year 20 if the system produces 9000 kwh/yr and about year 17 if it produces 10,000 kwh/yr. Like you say, there are different motivations. A person will drop $20-40,000 on a new car or truck for personal transportation, definitely not an investment, it never gets in the black, but instead is an ongoing expense. And ditto for nearly all other things a person buys. The same money in PV erases an ongoing expense and after time puts money in a person's pocket (in the black).

Based on the cost of my system, the electric rate structure in place where I live, and reasonable assumptions, I think the better question is: If you could, would you invest your money at a 5% annual return, tax-free, inflation hedged, and nearly risk free (guaranteed return)? If I could get this outcome, I likely would put all of my money in such an investment. That's what PV does for me, in addition to meeting many other motivations.

"getting away from the risk of price increases of the electric market ... being green ... being self sufficient" are "big value" for me too.


----------



## JP11

I think my rates for power are almost 50% higher than yours.  Thus my quicker payback timetable.

Not sure why solar can't be pushed more.  It's a LONG term solution for sure.  But with a system with near no maintenance requirements, and no moving parts.... seems that we just need to think more life cycle costs then strict ROI.

Like I said.. I did it because I like it.  Much like my biodiesel. That one's pretty easy.  I'm under a buck a gallon.  Pretty easy math on that one.  If it cost me 3.75 and diesel was 4.. I don't think I'd bother.

Sure are plenty of other things to 'waste' money on.  I wouldn't buy a set of golf clubs and go play, but I bought a 45 year old snowcat to restore!  We all have different wants.  Looking forward to sharing my numbers like you have.

JP


----------



## jebatty

If my rates were 50% higher, payback would be year 13. My grid tie utility buyback is full retail rate, so the utility buys from me at the same rate I buy from the utility.


----------



## woodgeek

JP11 said:


> Not sure why solar can't be pushed more.  It's a LONG term solution for sure.  But with a system with near no maintenance requirements, and no moving parts.... seems that we just need to think more life cycle costs then strict ROI.
> 
> JP



PV is going exponential now, doubling every 18-24 months, which is about as fast as anything gets adopted.

Your investment is not 'risk free' however.  It is possible that existing grid-tie arrangements will be modified not in your favor during your payback period, and almost certainly within the lifetime of the system.  For example, if that exponential keeps going, we could get to the point where there is enough solar to run the whole grid for a few hours around noon.  Will the utility force you to curtail?  switch to time of day rates, and give you a very low rate during these surpluses?  No one knows.

Projecting current growth rates says that such a 100% peak solar scenario will be reached in many US markets within 5 years.  

If we do get to that point, buying a low-cost storage system makes sense....store your own power, go off-grid or just use the grid for backup.  Current off-grid systems using Lead-acid run $0.30-.50 /kWh delivered.  Elon Musk says Tesla will make Li-ion batteries for EVs at $100/kWh capacity that last >1000 cycles, in <10 years.  That works out to be <10 cents per kWh delivered.


----------



## jebatty

I'm not too concerned about the future risk regarding rates. Pretty sure storage technology/price will be very competitive. Also an electric vehicle can be had to soak up the extra, as well as other options.  Electricity is a very flexible commodity.


----------



## JP11

With more and more people adopting PV.. I think the risk is low that buyback terms will get worse.

Maine is already not as good as some neighboring states which let you make excess power and be paid back.

I suppose a strategy to combat a regulation change would be to add batteries.  It's sure expensive.. but it's a way out if they changed the rules.   I think it's unlikely.

JP


----------



## woodgeek

Both the utility and the PV owner make $$ in the current grid tie arrangement.  Ironically, the risk is entirely a consequence of PV being too successful, and thus widely adopted.  I wouldn't worry about PV in Maine for the next 10+years.  Go for it.

In the markets currently approaching the limits of simple grid-tie PV penetration (HI, CA), the question becomes do the individuals buy the storage or do the utilities buy it, and pass the cost onto the grid-tie customers?  Right now, it seems the utilities are doing the latter, buying expensive storage, passing on the cost, and **forbidding** the connection of home storage systems to the grid (the argument being that grid operators can't control or predict what you do with that unit).  So PV customers will either have to pay for grid storage, or go off-grid completely, until a better way is worked out.


----------



## jebatty

I re-reviewed my PVWatts estimated performance, and I noticed that all of the input parameters I used were accurate, but also that I used a DC to AC Derate Factor of 0.98. PVWatts uses a standard 0.77 factor, and I have seen using a 0.87 factor for microinverters likely is more appropriate. Regardless, with a 0.98 factor, and my system nearly being right on the average, I am quite impressed with my Suniva panel and Aurora microinverter performance for Year One.


----------



## jebatty

On Aug 12 passed the 7MWh production point, 2-1/2 months to go for the first year and the target of 9.2MWh. First 14 days of August have been tremendous, 497 kwh at 35.5 kwh/day average.


----------



## JP11

Just got the phone call yesterday.  They want to come a couple weeks early.  Hole in the schedule means they should be here 19th.  Power company supposed to change out the meter on the 22nd.  I may get some August sun yet!

JP


----------



## jebatty

August production, which for the first 15 days was outstanding, was equally disappointing for the last 16 days: 535 kwh vs 291 kwh, total 826 kwh for the month. I again adjusted estimated annual production, changing the derate from 0.98 to 0.96 based on spec'd microinverter efficiency. The derate still is probably too low, 0.87 may be more realistic, but I'm using the numbers to "challenge" my system to out-perform the averages.


----------



## jebatty

Last winter I mentioned to my neighbor to the south that I was getting some shading from a few aspen trees on his property. A week ago he brought up that topic, and then said I could cut them down and use the trees for stove wood, but if any of the tree trunks were solid and suitable for 6x6 or 8x8 posts 10 feet long, he wanted to save those for his use. A great idea and a good use of the trees, and I offered to cant any such 10' logs on my bandsaw mill. Solid, straight aspen should make good posts, but it does need to be kept dry. I think the posts are intended for a future post frame storage building.

We identified about 9 trees at issue, and yesterday we cut them down. One had to be dropped quite carefully between two other trees, and we had wind to deal with also. I missed the wedge/cut direction of fall just a bit, and that tree hung up as it came down. Today's task will be to pull that tree off the tree it is hanging on, next find what good 10' log sections are available in all of the cut trees, and then haul out the logs along with the balance of the trees for stove wood processing. I hope that covers the balance of my need for 2015-16 winter stove wood supply 

The same neighbor has a quantity of red pine that needs thinning, and I also offered (price to be negotiated) to saw those logs for posts or lumber, as the neighbor desires. Help and get help as needed makes for a good neighborhood.


----------



## jebatty

... meanwhile, heavy clouds are infecting the September sun and electricity production is falling below the goal for the month. Hopefully, the last half of September will see the sun shine.


----------



## Grisu

jebatty said:


> Last winter I mentioned to my neighbor to the south that I was getting some shading from a few aspen trees on his property. A week ago he brought up that topic, and then said I could cut them down and use the trees for stove wood, but if any of the tree trunks were solid and suitable for 6x6 or 8x8 posts 10 feet long, he wanted to save those for his use. A great idea and a good use of the trees, and I offered to cant any such 10' logs on my bandsaw mill. Solid, straight aspen should make good posts, but it does need to be kept dry. I think the posts are intended for a future post frame storage building.
> 
> We identified about 9 trees at issue, and yesterday we cut them down. One had to be dropped quite carefully between two other trees, and we had wind to deal with also. I missed the wedge/cut direction of fall just a bit, and that tree hung up as it came down. Today's task will be to pull that tree off the tree it is hanging on, next find what good 10' log sections are available in all of the cut trees, and then haul out the logs along with the balance of the trees for stove wood processing. I hope that covers the balance of my need for 2015-16 winter stove wood supply
> 
> The same neighbor has a quantity of red pine that needs thinning, and I also offered (price to be negotiated) to saw those logs for posts or lumber, as the neighbor desires. Help and get help as needed makes for a good neighborhood.



Wow, what a great neighbor. Not sure what mine would say if I suggested cutting down their trees to expose my PV installation to more sunlight. In fact, I have not gotten one yet because some trees of my neighbor are shading the part of the roof during the morning that I would like to put them up.


----------



## JP11

Glad you're getting rid of shading.  Curious to see what mine works out to.  I've got to move some palleted wood to give room to drop my potential problem trees.  My one giant oak is split up small and top covered. Probably 1.25 cords.  Nice.. and it BLEW over so no scary moment of wondering if it will catch the 14k watt power lines.

JP


----------



## Where2

Thanks for the reminder, I need to trim a few branches in the top of my avacado tree in the backyard before late November. 

Most of my shading on my second floor roof PV array comes from a royal palm in the neighbor's yard to the east and an oak in the neighbor's yard to the west. Not much I can do about either of those two shade sources. Can't cut the top off either tree.


----------



## jebatty

Seven weeks to go to the end of the year of PV. Since start-up on Oct 28, 2013, my meters show the following:
9973 kwh bought from the utility
5998 kwh the utility bought from me
11809 kwh total used
7834 kwh PV production
1836 kwh PV production used on-site (balance sold to utility)

Also, as of billing date Sept 8, 2014, my total utility credits now are $661.00.


----------



## jebatty

PVWatts has another updated data set (as of Sept 8, 2014), which now also includes access to SolarAnywhere data. I now have data for a 10 km grid including my site, rather than data from a far more distant location, and once again I have updated by estimate of production. That will show on my September report of performance.


----------



## jebatty

Today production hit 8MW. September so far has been extremely variable, clouds and virtually nothing, then a couple of clear days.


----------



## JP11

Me too.  Bad days make less than 10kwh.  Good days lately are over 60.

Averages still about 10% above PV watts calculations.  How do you compare looking at averages month to month?


----------



## jebatty

At the end of Sept I will post a new chart with the new PVWatts data to show how I match with the averages. One goal for the 1st year is 10,000 kwh, and I will not make that, absent an incredibly sunny end of Sept and Oct. 2nd goal is to erase my electric bill -- that goal will be met, I'm pretty sure. 3rd goal is to use no more kwh than my system produces in a year -- after lots of serious conservation, still a good ways to go on meeting this goal.


----------



## JP11

Since I started in late Aug.. I don't have that big 'bank' of kwhrs going into winter.  Not sure if I'll make it with zero bill all winter.  We shall see.  System is oversized, so we'll see.

JP


----------



## jebatty

September finished well, falling short of the predicted average by only 3kwh. This chart uses new PVWatts data, the net effect of which from the prior data is to move monthly kwh amounts around a bit and increase total annual estimated production up about 1 MW to just over 10 MW. The big deficit months were Nov, Dec and Jan, and totaled 991 kwh. For Feb-Sept the total additional deficit was 139 kwh. With just one month go to finish the first year, it is obvious I will not meet the predicted annual average. 

Predictions are just that and nothing more. I am very satisfied with my system. A little wait and see, but credits plus production should now cover usage going forward, and I am not expecting any future electric bills. Energy price security, priceless.


----------



## JP11

I can't recall.. did you change PV watts calculations?  I ran about 100kwh over predicted.  About 7% above.

Happy so far.  Remains to be seen if starting in late Aug.. if I can build up enough of a credit bank to make it thru winter without buying power.  Worst PVwatts says 750 or so for jan.. with house using 1200 last year.  We shall see.

Still haven't seen the first power bill yet... but they've read the meter.  Kinda looking forward to it!

JP


----------



## jebatty

> did you change PV watts calculations?


Yes. My first estimates were based on 2% derate, which was do to my ignorance. With each PVWatts data update, plus with what I have learned, I think my derates now are pretty close to actual. Last Fall and early Winter were extremely cloudy. Hence the low production. October is starting out with dense clouds and mist. Production today was 3 kwh!


----------



## JP11

3!!  and I thought I had it bad today at 9.142    My 'low water' mark is 8.975   Best so far was 74.031  

It's fun to watch.  I've got dailys on a spreadsheet which I have set up to watch monthly average.   SMA website tracks it all, and will spit out .CSV file that cuts and pastes pretty easy into excel. 

JP


----------



## jebatty

I received the electric utility bill for the monthly period ending October 8: -$67.00 for the month and $728.00 total credits accumulated. 

Nine more days to October 28 and the system will finish its first year of production. October so far is producing just about dead-on for the estimate of 757 kwh for the month, being at 455 kwh through October 19. I expect for the monthly period ending November 8 there still will be a net credit, but then due to supplemental electric heat I will be using credits for periods ending Dec, Jan and Feb 8, and I expect that accumulated credits will pay all of the bills due. If experience the second year is close to the first year, my bill for period ending March 8 will be slightly back into producing net credits.

It is very nice not to have to pay an electric bill each month.


----------



## jebatty

Today, Oct 28, is the one year anniversary of my system. The 26 micro-inverters report total output of 8965 kwh. The production meter at the house reports total 8880 kwh. I'm assuming that the 0.9% difference is caused by line loss over the 280 feet of underground cable between the panels and the house and/or meter tolerance. Following the end of October I will have a more complete report and analysis of the first year of operation, with which I have been very satisfied.


----------



## JP11

Cool to see.  I think I'm 'under' for oct.  Been awful rainy.

Anxious to hit the one year point.  I think that's a realistic time to figure out a true payoff.

JP


----------



## woodgeek

I was always of the understanding that annual output varies ±10% or more.


----------



## Where2

woodgeek said:


> I was always of the understanding that annual output varies ±10% or more.


We'll see. I'm already 2.5 months into year #2. No complaints from me about my $43 electric bill last month, or even the $57 bill for September.


----------



## jebatty

Hard to believe that one full year of PV is in the bank. The market was "down" a bit, with an ROI of 4.58% vs 5.18% had the Average PVWatts production been met. The "loss" occurred primarily in Nov, Dec and Jan, with production falling short by 991 kwh, and the balance of the year failing to meet average by 182 kwh. No complaint, however, because the same money invested in a CD would have produced only about a 1% return on a one year CD. But, one year does not an average make, so on to Year 2 and wait and see what the outcome will be.

As of Oct 8 credits on my electric bill were $728.00, and additional credits will be added with the billing and meter reading as of Nov 8. Based on last year's bills for Nov ($35), Dec ($59) and Jan ($54), and credits starting to accumulate beginning with Feb (-$41), I look forward to receiving a healthy check from my utility for the excess credits. One way to look at the check for excess credits is to consider it as dividends for an investment I have made in my utility to provide it with Net Zero power, and a dividend for an investment in the community to provide all of us with cleaner air to breath, fresher water and an improved environment from reduced acid rain, mercury and other pollutants, as well as a smaller hole in the ground from reduced usage of coal. 




I also accumulated other data which is informative. I used 7120 kwh for utility interruptible service at a reduced rate (electric heat and domestic hot water, about 100 kwh/mo for dhw and average 500 kwh/mo for heat). I also used 3522 kwh of utility general service (about 300 kwh/mo), for a total of 10,642 kwh of utility grid usage. The utility also bought from me 6852 kwh, and I directly used 2070 kwh of PV production. My total electric usage was 12,712 kwh (1060 kwh/mo), which I believe to be above average because of above normal usage of electric heat due to the very cold winter last year. 

During this first PV year we also converted nearly all of our lighting to LED. We also are very good at turning off lights when not needed and we have most electronics on power strips which we turn off when not being used. Except for the wood stove which meets most of our heating needs, our house is all electric, and substantial usage would relate to the electric clothes dryer, stove top, and oven. Any additional electric energy conservation at this time would be very difficult.

The final observation is -- very satisfied with the PV and look forward to future dividends for self and community.


----------



## woodgeek

Congrats Jim, I am glad you are pleased with your purchase.  If I had a solar viable site, I would consider the same thing.  To me the exciting thing is you made more power than you used.  A great investment for you, your community, the global RE marketplace and an example for others to learn from and follow as to their ability.

That said, the ROI number leaves me a bit cold. CDs? The SP500 made 17% last year, so I figure you are currently down 10% as an opportunity cost, net taxes.


----------



## jebatty

Well, you could make that argument. You also could make the argument that in 2002 the SP500 was down 37%. Or from 1969 - 1979 the CAGR of the SP500 was -2.66%, for example. How does that work for you? We've discussed this before, namely that solely as an investment a good argument can be made that an indexed SP500 fund will do better, by luck of the draw in the short term (could also be disastrous though), and quite likely in the long term, and "Over the very long run, the stock market has had an inflation-adjusted annualized return rate of between six and seven percent." http://www.moneychimp.com/features/market_cagr.htm

Unless we enter another very cloudy solar winter where the sun doesn't shine you know where, PV will kick out its steady, annual return, probably in the 4.5% to 5.4% range on the initial investment (assuming no change in electric rates). And if the 20 year average increase of 5%/year in electric rates is taken into account, the rate of return is much, much higher, and it is a near certainty that electric rates will rise. http://www.eia.gov/todayinenergy/detail.cfm?id=17791

My current rate is $0.115/kwh. If the rate rose 10% to $0.1265, my return on the initial investment just jumped from 4.58% to 5.55%, a 21% increase. Incidentally, my utility just announced a rate increase in its interruptible power rate.

In other words, PV is secure and rate inflation adjusted. And if and when a VOS tariff may apply to solar (MN is in the process of developing that), the rate of return will climb dramatically, probably double or more. And until then, my investment is making your life and our environment healthier, and for your thanks you are very welcome!


----------



## woodgeek

I think there are plenty of great reasons to invest in solar, and if you already have lots of exposure to index funds, I could see solar as a better choice than a lot of bond funds (not to mention CDs, ugh) to balance a portfolio.  I'll agree that future electricity cost will roughly track inflation (based on the last 30 years of data).  There are decent arguments to make both to the upside and the downside.

Looking over your spreadsheet at post #79 in this thread, I did not see any explicit accounting for the *depreciation* of the array (at least on the left), or things like inverter replacement (apologies if you discussed this elsewhere).  That sheet seems to value the array proportional to its (projected) output.  That is, you figure output drops 0.5% per year, and appear to depreciate its value at the same rate.  If you figure your array has 0 value in 30 years, i.e. scrap, I think that knocks down your ROI considerably.

Ok, looking at the numbers of the right, I CAN interpret them as a complete writeoff of the original capital.  If your net current value is +$12k in 30 years on a $22k investment, then you are seeing an (inflation corrected, i.e. current value) gain of 12/22 = 55% over 30 years.  That works out to a *1.46% CAGR* for that period, on a real basis ( 1.55^0.03333=1.0146 ).

So, as I see it you got something you wanted at effectively zero cost to you over a 30 year horizon.  Nice.  Lots of good intangibles.  Are you 'making money'...not so much.


----------



## jebatty

WG, I always (almost) respect and agree with your analysis. I am a moderate risk taker with some solid balance of security. So, at my nearing 70 years of age, I still have considerable stock market exposure, both in individual stocks and in ETF's, including the S&P500. And, because a long term market downturn could be a major upset in the retirement of my wife and me, I also maintain cash and equivalents to weather the downturn. When I was working full-time, self-employed, security came in the form of quickly paying off the mortgage and owning the home free and clear. Not the best place to put money in retrospect, but gave great peace of mind and freedom not to be bound to my employment, both great stress relievers. Essentially, my wife and I could live on her income if I would become disabled.

I look at the PV as another security enhancement with a positive financial, personal, social and environmental return, all things which mesh well with my values. In the final analysis, we used a small slice of our assets to obtain considerable peace of mind. Heck, I've made speculative investments also with a small slice of our assets, most of which have ended up doing very well and a few which have bombed. PV is not speculative, and it is an exchange of money for something of solid, long term value.


----------



## woodgeek

Indeed.  As a place to park value... inflation+1.5%/yr is better than cash and better than gold for the last several years.


----------



## JP11

Very much how I look at my system too. I look at as.. If everything goes to pot.. what have I got to spend to keep my home running.

With biodiesel to drive, wood to heat, and solar PV... the answer is.. not much!

JP


----------



## Redbarn

jebatty said:


> Today, Oct 28, is the one year anniversary of my system. The 26 micro-inverters report total output of 8965 kwh. The production meter at the house reports total 8880 kwh. I'm assuming that the 0.9% difference is caused by line loss over the 280 feet of underground cable between the panels and the house and/or meter tolerance. Following the end of October I will have a more complete report and analysis of the first year of operation, with which I have been very satisfied.



Many thanks for posting the years data. It is of great value to a solar wannbe like me to see how an actual system performs.
It is also very interesting to see the real world effects of cloudy days, hot summer days etc. etc.
Your efforts are much appreciated.


----------



## jebatty

JP11, like you I heat with wood, no electricity required for the house. And with my excess PV credits not only is our house now energy NetZero, but also my shop. 

Redbarn, here is a record of October production. You can see how low production can go with heavy cloud cover; also how high with a sunny day. October was running +100% until the last few day of heavy cloud cover.




I am happy that this is helpful. After one year of daily record keeping, I do not plan to continue that any longer. I will be watching for winter production though to see if on clear, cold days production gets into the high 40kwh range like it did this last winter. The all time high was 48kwh on one day, about 5 days at 47 kwh, and a fair number in the 42-46 kwh range. My highest day of non-winter production was 43 kwh, not many days over 40 kwh, and quite a few days in the high 30 kwh range.


----------



## JP11

jebatty.. how are you capturing the data?

I can go online and see real time, or historical.  I push a button and get a CSV dump of each day of the month. I then paste into a spreadsheet.  I'm still tweaking it.. but here it is.  oops.. won't let me post XL

JP


----------



## jebatty

For this first year, because I wanted to have an accurate baseline for the future and also to better understand my system, I physically read the meters every day: 3 utility meters for reduced rate interruptible, general, and buy-back, and then my own meter for production. For some brief periods when I was gone for several days I averaged the meter readings over the period. 

The daily record has been very helpful to fully understand the impact of snow cover, shading, cloud cover, and soiling of the panels. As it has turned out, reduced output from soiling so far has not resulted in a measurable reduction in output. Since my array is ground mount, it is easy to do and I have regularly cleared snow from the panels during the winter.

The Aurora microinverter website collects data on total output with a reading every 15 minutes. The website also shows the curve for the day. This can be downloaded in a csv text file which can be read into a spreadsheet, although I have a separate graphing program which I use on occasion. And the website similarly provides 7 day, 30 day, 12 month, week to date, month to date, and year to date csv data and charts, as well as lifetime output. All of this data can be viewed and downloaded for past periods as well. The website then also shows all the panels with the output of each panel as of the last reading. 

The website collected data is at the array itself. As I have learned, the meter reports on output are about 99% of the array output data. I attribute this difference to line loss over the 280 feet between the array and the meter and/or meter tolerance. At the array July was the month of highest output, at 1,077 kwh (1,067 meter) and December was the lowest at 268 kwh (268 kwh meter). Mar, April, May and June were all in the 900-999 kwh range; February, August, September and October were all in the 700-899 kwh range; January was in the 400-499 kwh range; November was in the 300-399 kwh range; and December was in the 200-299 kwh range.

In addition, I can visually see instantaneous output by panel over an ethernet connection to my computer. This output also includes total array output since installation, CO2 avoided, and the status of each panel. There have been very uncommon error reports on a panel, and these have been easily cleared with a reset. The errors have related mostly to the grid being outside of the parameters (I remember one occasion grid voltage was too high), or a communication error with a panel. Wifi is available to do this as well, but my panels are too far away for a wifi connection. 

The only issue that I have had that was not easily corrected is that in very cold weather (roughly -15F and below) the ethernet monitoring device (CDD) will not operate. The CDD is spec'd to operate down to -5F. This does not affect panel performance or website collection of data, only the ability to see instantaneous panel performance. I have the CDD installed in an outdoor plastic electrical box, and yesterday I just completed installing in the box insulation and a snap thermostat to light a 4 watt light bulb in the box which should provide enough heat to keep the box interior warm and prevent this issue during the coming winter.

A summary perspective: it is helpful but not necessary to be "handy" with electricity and mechanics in owning a PV system, just like it is helpful to be "handy" to tackle the myriad of other maintenance issues in owning a home and operating a household. My system was professionally designed and installed in a turn-key operation. The designer has remained available to answer the few questions that I have had. The installer has not needed to return to repair or otherwise fix any problem with the system during this first year. Maybe best of all, my utility likely will be sending me a check this spring to pay me the excess credits I have accumulated and which were not used up over the winter. C'est la vie!


----------



## JP11

I've had just a couple of 'communication' issues as well.  One of the inverters will occasionally just not report.  I've gone as long as 3 days.  It does however come back online, and will then go back and fill in all the data graphs on what it was doing back then.  Must be a descent amount of onboard memory on the inverters.

I haven't been thru a winter yet.  Inverters for mine are inside the barn.  It's insulated, but unheated.  We'll see.

JP


----------



## jebatty

Just noticed that "views" now are over 10,000. Either my periodic posts have been very funny or actually helpful to others considering PV. Hope both are true.


----------



## Redbarn

jebatty said:


> Just noticed that "views" now are over 10,000. Either my periodic posts have been very funny or actually helpful to others considering PV. Hope both are true.


JEB,
The 10,000 plus posts show that your efforts have been closely followed. 
I probably have contributed a chunk of those with my frequents checkins to look at your data.
Your efforts are much appreciated.


----------



## jebatty

Records are made to broken. I think these first 10 days of November have included the cloudiest ever for production:
Nov 3: 6.8 kwh
-- 4: 2.2 kwh
-- 5: 2.5 kwh
-- 6: 1.8 kwh
-- 7: 3.8 kwh
and the the record breaker, Nov 10: 0.2 kwh


----------



## JP11

Low water mark.. 

2.105kwh  11/2 

worst day since install Aug 22


----------



## Where2

Wow, those numbers are depressing! (because I know your PV systems are larger than mine)
11/21/13 - 1.76kWh
11/09/14 - 1.83kWh
01/30/14 - 2.04kWh


----------



## JP11

Where2 said:


> Wow, those numbers are depressing! (because I know your PV systems are larger than mine)



Ok.. High water mark... 
74.031 8/29/14  

We shall see what it will do in spring sunshine.  At least when I'm cursing the sun for ruining our snowmobile trails, I'll be happy about the PV production.

JP


----------



## jebatty

I just received my house electric bill for the period Oct 9 - Nov 8, which completes 12 full months of billing experience with PV. In this chart Dec 2012 would have been zero PV, and Dec 2013 would have been the first full month of PV (Nov 9 - Dec 8; PV went active on Oct 28). The "Net Bill" is the bill for electric usage after reduction for net meter buy-back. I expect that the Dec 2014 bill will show a reduction in the accumulated credit, as will Jan/Feb 2015, and if the second year experience is about the same as the first year, the Mar 2015 bill should show an increase in the accumulated credit. The accumulated credit will off-set billings I have on two other meters, my shop and a rental house.

The spike in winter billing relates to supplemental electric heat and the spike in summer billing reflects use of a dehumidifier in the basement of our house.


----------



## jebatty

Based on interest in this thread, I will keep posting monthly data.


----------



## JP11

Glad to see I'm not the only one that 'fell on my face' for production.  I didn't make PVW numbers for last month, or this month.  I only stared Aug 22, so not a lot of KW in my 'bank' with the power company.  I think I'll have to, GASP.... PAY for some electricity in January.


----------



## ironpony

I am very glad I took the time to read this thread. I am building a home in St Croix USVI and have not considered solar power very seriously. There are systems on the island and the best you can do is net metering. I think I am going to look into the cost and roll it into the build price. Would be nice to have "no" electric bill. Oh and the weather is 80 and sunny everyday.


----------



## JP11

how stable is the power grid?  that would be my deciding factor on 'island power' and leaving off the batteries and going net meter.

JP


----------



## jebatty

If I take "stable" to mean that the grid will stay within the parameters of the micro-inverters, then I recall only once or twice that the grid went above the voltage parameters and the micros briefly shutdown. If it means power outages, then where I live the grid is quite stable. Importantly, I do have a portable backup generator, 5500 watt - 240 volt, with a transfer switch to operate "critical" circuits in the event of a long power outage, which has only happened once of longer than 6 hours in the last 23 years. Generator circuits include the well pump, refrigerator and freezer, most general lighting (nearly all LED), microwave, and a circuit for the computer, DSL, internet, and TV.


----------



## JP11

jebatty, I was replying to the gentleman talking about St Croix.  It would really stink to spend the money on a PV setup, but still not have power if the utility on the island was not reliable.  Might be better to have a smaller system with batteries and have dependable power.

JP


----------



## jebatty

Dependable power all the time would be great. Yet, a very large part of the world has nowhere near that kind of power available. Even a small system with batteries is really expensive. In a place like St. Croix, VI, where it is sunny all the time, I think it would be quite doable to adjust to a lifestyle based on PV with an inverter, and very minimal battery capacity for the night. What say you, St. Croix, VI?


----------



## Where2

jebatty said:


> In a place like St. Croix, VI, where it is sunny all the time, I think it would be quite doable to adjust to a lifestyle based on PV with an inverter, and very minimal battery capacity for the night.



^^^^ Except that most Americans coming from the US would want to have air conditioning... For some reason, average high temps above 85°F for all months, and average lows dipping only in to the low 70's combined with humidity makes people want A/C. Sunny all the time comes with humidity all the time on those tropical winds, and an occasional hurricane every now and then.

A 3-second gust of 170mph should be in the design criteria for any USVI PV system.  My array is 2.5 miles, as the pelican flies, from the Atlantic. A little more expense and time spent up front to keep your home and array together pays off exponentially after a storm when repair materials and labor are scarce.


----------



## jebatty

I got an early Christmas present from the electric utility. Would have had a $34 net bill for the monthly period ended Dec 8, but accumulated net metering credits erased that. Electric bill without PV would have been $63.75, PV production during the month reduced that to $34.00, and accumulated credits brought the bill to $0. Credits of $749.00 remain.


----------



## JP11

I'm almost out of credits.  Been a bad couple months.  With my system coming online late in the summer..  I knew this would happen.

I'd say I'm anxious for spring sun... but in reality that spring sun ruins my snowmobile trails!  mixed motivation


----------



## peakbagger

JP 11 how is the snow sliding off? . I got 10" of wet stuff that slid about 6" and froze on the edge of the roof so I am down an array until  we have a couple of warm sunny days to break it lose.

I can commiserate on the first winter when I ran out of credits. All you do is dream about next winter.


----------



## JP11

It's been pretty warm.  It has pretty much taken just one full sun day to get rid of most of the snow.

I'm pretty surprised how bad my shading is with the sun so low.  I've got a shallow hill, and a couple pines on the OTHER side of a high tension power line are even shading me.  I've got one more hemlock to hack of my own.  But the production is so low anyway.. not sure it'd make a ton of difference.  I just need to wait for a day when the wife is away to make the tree disappear!

JP


----------



## peakbagger

5 more days and the sun starts getting higher


----------



## jebatty

Where I live the sun at solar noon is 19* above the horizon. Surprised me too how very distant trees provide shading. I still get about 4 hours of pretty good sun with production at 50% and higher of rated output. Fall and early winter sun does not have the insolation that late winter and early spring have, and for my first year the highest peak and the highest daily production occurred in the Mar - May period. I attribute that to a very clear sky, very little dust/humidity in the atmosphere, and cold temperatures.


----------



## jebatty

December seemed to be extraordinarily cloudy, but kwh were nearly the same as December 2013, and the Nov-Dec total for 2014 was a little higher than 2013. The seven highest production days each were a little over 20 kwh, six days were between 10-20 kwh, and 18 days were less than 5 kwh, with all but one of those 18 days being less than 2 kwh. Averages are just that, but my 2 year Nov-Dec average is coming in much less than the PVWatts calculation for my area. The really great news is that I still have $749 in credits to apply to the Jan and following utility bills.


----------



## CombatChris

jebatty, I'm sure I've missed it, but could you please let me know if you can cash out your credits into, you know, cash? Or does it remain forever as a credit to be applied to low production or high usage months?


----------



## jebatty

Utility tells me that it will send me a check whenever I want.


----------



## CombatChris

So really it's money in the bank. That's awesome.

You should get them to cash out so you can invest it - get your money working for you.


----------



## jebatty

I wanted to use my system for a year before making any decisions, and it was easiest to let the credits accumulate. I have another account with the utility (my shop), and I will be transferring some credits to that account. Last year I got my first credit in excess of billing with the March bill, and if that happens again, I will know pretty well how to plan the allocation of credits to erase the shop electric bill. The PV, along with the Tarm gasification boiler in 2007, have been two of the most fun investments which have erased major expenses, the PV by watching the meter and letting it pay me, and the Tarm by greatly reducing the need to cut stove wood and leaving the propane and electric heat man out in the cold.


----------



## JP11

I ran out of credits last month.  ( i started Aug 22, so no big bank)  Power bill was 40 bucks.  I'm running 20 to 25kwh on a sunny day now.  It only gets better *other than the snow days.

At what rate do they pay you if they cut you a check?  If I have excess next spring I'll send the credits to my parents house that I own.  I'd just need to put the power bill into my name.

JP


----------



## jebatty

I guess I'll find out for sure when I request payment, but the billing clerk I talked with said the utility could sent it monthly as it is available or anyother way or when I wanted it.


----------



## jeanw

jebatty said:


> I guess I'll find out for sure when I request payment, but the billing clerk I talked with said the utility could sent it monthly as it is available or anyother way or when I wanted it.


 okay how much you mentioned earlier in this thread $4.50 a watt.???
 so how much will it cost us ?  been reading about solar books magazines etc for years. Only got 3 15 watt HF panels so far sitting in toolshed...
Not  reinstalled since we moved.ended up using the 6- T 105 s Trojans  for my used golf cart to get around on this property. then days ago bought 6 new t 105 for my cart.. acting slow.... so the 6 T 105 are freed up again.
 WILL EXPLAIN MORE IN MY NEW POST..
THANKS  yall


----------



## jebatty

I replied to your new post. The posts on my PV system show my costs. I do not know what your costs would be.


----------



## jebatty

Bummer! Utility called yesterday and said it made a mistake on my billing, had given me a double credit for net meter buy-back. Good news is that this was a billing computer programming error, and better news is that the utility will not be asking for a refund.

My utility digital supply meter reads only forward on kwh supplied to the house from the utility. It does not roll backward on buy-back. I have a separate digital buy-back meter that only reads forward power from my panels into the grid. I was given net-meter credit based on the buy-back meter, and also given a credit as though the supply meter had also rolled backward.

Although my credits are now 1/2 of what I reported, the end result actually is about what I had predicted. My historical annual kwh based on usage has been about 12,000 kwh, Running the numbers from 11/01/13 - 10/31/14 I show 12,626 kwh used, a little higher than average but also the winter of 2013-14 was very cold and we likely used more electric heat than normal in our basement.

Of the 12,626 used, about 7,120 kwh is electric heat and electric hot water which is interruptible and is billed at about 1/2 of the general service rate (equivalent to about 3,560 general service kwh). This is also on a separate meter which is not affected by the PV. The general service meter showed usage of 3,452 kwh. I have a solar production meter owned by me which showed total production of 8,894 kwh, and the buy-back meter showed 6,840 kwh, meaning that 2,054 kwh of PV was used directly in our home. Kwh buy-back is at the general service rate, so I had general service credits on 6,840 kwh and general service equivalent purchases of 3,560 +3,452 = 7,012 kwh, nearly a wash.

The PV goal was to erase our electric bill and that goal essentially has been achieved. We might need a little more conservation on electric usage, and maybe our conversion over the year to all LED lighting will be enough to ensure no electric bill again, not even a small one.

One other thing, electric rates were raised for 2015 and also net meter buy-back was increased accordingly. That is a real positive of net metering: inflation protected rate of return.


----------



## JP11

Bummer.

On the sunny side over here.. Paid OFF my solar this morning.  Now the cloudy days don't bum me out as much.



JP


----------



## begreen

Congrats!


----------



## jebatty

January 2015 was an incredibly cloudy month, highly unusual. PVWatts predicted production for January was 642 kwh, actual was 337 kwh, 52% of predicted. Nov 2013 - Jan 2014 total production was 1025 kwh, while Nov 2014 - Jan 2015 was 950 kwh. Last year I never was able to fully make up the deficit of low winter production. Hopefully this year will be better.


----------



## JP11

Don't feel like the lone ranger...

I don't think I made 30% of PVwatts for Jan.  Feb not starting much higher.. with 3 foot drifts on the roof.

JP


----------



## jebatty

I have a virus. The virus has evidenced that I use more kwh than my PV system produces. The PV provides 75% of the house kwh usage, but I also have a shop on a separate meter. Adding 4-5 MWH of PV annually would kill this virus. So, I just contacted my installer to get a quote on doing this. I already feel my fever dropping.


----------



## JP11

LOL.. I've been blanked out for a few weeks, after a few days of production, blanked out two weeks before that.  Huge snow drifts.  Haven't seen warm temps at all.

The only reason I'm not climbing the walls from no solar production.... I snowmobile, and just restored a groomer.. so I'll live with no sun, and lots of snow instead!!


----------



## jebatty

My system has an Aurora Power-One concentrator data device (CDD) which collects the data from the 26 microinverters and then uploads the data to the Aurora website. Up until today I needed to visit the website to download the available data: daily combined data (one minute logging interval), 7 days, monthly, etc. Historical data similarly available. In addition my computer could access real time performance of the array, showing real time output total, as well as the output of each of the 26 panels. No data logging on this, however. 

Yesterday I contacted Aurora and inquired as to whether there was a means to collect more data from the array, since the CDD obviously was collecting data and forwarding it to the website. Tech support immediately activated me for in depth access to all of the data on the website, rather overwhelming. And then the tech showed me how to program an automatic data push to my computer of whatever data I wanted. I set up two data pushes, one for combined daily output (one minute logging), and the other for daily output of each of the microinverters. The microinverter report likely will show impact of shading on each of the panels. I expect the data files for yesterday to arrive sometime today. Then I need to explore what else would be interesting to know about my system.


----------



## JP11

Cool.  I'm headed for a complete BLANK for Feb.  Snow is deep, and were getting more.  I'll play with solar in April!

I wouldn't see that kind of fidelity, with two inverters, but I bet it would break it down into the 8 primary wires.. so 6 panels each.


----------



## tmarch

My 6K system just celebrated it's 3rd birthday and is looking better all the time (potty trained?).  Figured my ROI @ roughly 7% without the tax break, making it 10% with the tax break.  I took the $ from a retirement IRA to buy it, so in effect it did save me the tax on that portion.
My average utility cost is .2026 per KWH which is higher than most, making the investment even better.  I will add to the system if needed, but for now it 0s out my usage for 10 months of the year and any overage is bought by the utility @.0325 cents per KWH so not planning to.


----------



## jebatty

It's been a long time for a "perfect" solar day - no clouds, temps -11F to +7F. This was about as close to perfect as it gets.


----------



## DBoon

jebatty, where is the snow?  I've heard that MN is pretty dry this year, but that is ridiculous. 

My ground mount is covered under 3 feet of snow, my wife tells me, and I've been traveling on business for 2 weeks and can't do anything about it...


----------



## JP11

Every one of my 48 panels is under snow.  2 inches on some.. 4 feet on others.  NO warm weather to be had.  Snowmobiling is AWESOME though!

JP


----------



## jebatty

Yesteday, Feb 27 was another perfect day, and another 44kwh of electricity. Wow. Today the forecast is for clouds and maybe some snow, but 700+ kwh for the month is within reach. Since production already is above the Feb average, there will be some makeup for the dismal Nov-Jan period when cumulative production was 646kwh below average. 



> ... where is the snow?


The picture was taken in Fall, but we practically have no snow, about 6" on the ground. And with all the very cold temperatures, frost is deep and septic tanks, drain fields and water lines are freezing up for many people. I now have tank heaters in our two septic tanks, each being on a timer that doses the tanks with 3 hours/day of 1500W heat.


----------



## JP11

I bet you're getting a lot of reflection from the snow.  44kw on a winter day is awesome.  They are talking rain mid week for us. if that snow comes off mine it's going to make one hello of a snowbank!

JP


----------



## jebatty

I also think snow reflectivity is a major factor, along with cold temperatures. Considering limited hours of sun and 44 kwh on Feb 27, and an all time daily high of 48 kwh on Mar 15, 2014 (snow cover), with summer production in July 2014 that had a daily high of 41 kwh and exceeded 40 kwh on only three days, the impact of snow and cold is readily apparent. A month of sunny, snow cover and cold March weather would out produce a month of sunny, hot July weather.


----------



## JP11

Isn't that what you PV watts shows?

May is supposed to be my 'high water' mark.  We shall see.  Maybe it's only because my system is new.. but with 12.2kw (rated power, which I know is a farce)  I'm maxing out my two 5k inverters.  Thus I was thinking the cold wasn't as big a factor on the panels.  Manufactures 'optimal' power should have my output at 8.8kw... but in full sun I'm for sure making 10.2kw.

guess we'll see how they panels deteriorate.  Maybe your panel output is sized so that your inverter  (AH.. I just remembered, you're micro inverter) so.. if you're panels are new enough to still be 'out producing' the optimal rating.. you're capturing that power, where I am limited by inverter.

Sound right?

JP


----------



## jebatty

Could be. In 2014 March and July were the two highest production months, July at 1077 kwh and March just a little behind at 986 kwh, and April a close third at 667 kwh. 

My panels are rated nominal at 265W (6.89kw) maximum. The microinverters are rated at 250W nominal (6.5kw), 260W (6.76kw) maximum, and 265W (6.89kw) maximum usable DC. In winter full sun, I commonly see peak output in the 6500 - 6700 watt range, the highest into the 6800 watt range.


----------



## jebatty

February turned out to be a very good month for PV, after poor showings for Nov - Feb. Yet, just a little bit behind last year.


----------



## begreen

jebatty said:


> It's been a long time for a "perfect" solar day - no clouds, temps -11F to +7F. This was about as close to perfect as it gets.
> 
> View attachment 154770



Our curves are finally starting to take a bell shape as the sun starts getting above the treeline. Nov-Jan is pretty much a no production time for us. We are on the north side of a large hill and many trees out here are tall evergreens. On the plus side we have pretty long daylight hours in the summer due to our high latitude.


----------



## jebatty

You will have achieved a "sunburn" when you get your first full bell curve. Very satisfying.


----------



## begreen

Right now the curve looks more like the snake that swallowed the elephant.


----------



## jebatty

Agreed yesterday to add 5.4kw to my PV system. Expect it to be installed and producing by early April. The added kwh should make a big dent in kwh usage in my shop and farm property.


----------



## jebatty

1 MW in 30 days! The Feb 14 - Mar 15 period showed 1,013 kwh of production! Makes the mind twist a bit to realize how cold weather and clear skies, sun still low, can outproduce almost every other month of the year.


----------



## begreen

That's fantastic. Helps a lot to have good southern exposure.


----------



## jebatty

March magic in play. March 15, 2014, was my highest single day of production in 2014, 48 kwh. Yesterday, March 17, 2015, reached 47 kwh for the day. Would not surprise me to see that being the highest single day in 2015. The first 17 days of March have averaged 35 kwh/day.


----------



## JP11

I think I need a couple more warm days.  I show one inverter only producing.. and it's making 4kw +

They are only rated at 5.  So I SHOULD be making good power when the last of that 4 foot drift is gone off my array.

JP


----------



## jebatty

March 2015 did not disappoint. Feb-Mar 2015 nearly matched the same period in 2014. The footings have been poured and the array mounting posts set for the 5.4kw addition to my system. Within a week I'm looking for the panels to be mounted and the system tested while awaiting utility approval to go on-line.


----------



## JP11

You're off to a better start than I am.  Last three months:

Jan 33%
Feb 5%
Mar 37% of PVwatts estimate.

But we had an AWESOME year snowmobiling.    I sold the snowcat I restored, and bought another one. 

Last few days have been pumping out 75kwh per day.

So you'll be at 12kw?  I just looked over incentives for my copilot this week. He's in SC.  30% federal, 25% state credit. Then something like retail plus 4c is what it looked like to me.  he's planning on 20kw!  

I got impatient.  I could have waited a couple more days.  I don't think I'll do it again.


----------



## jebatty

Do you have much hydro in Maine? The snow melt should be good for that. California is under major water restrictions due to lack of snow. We had practically no snow this winter either, plus very erratic weather and extremely cloudy Nov-Jan. I'm sure you will look forward to snow-clear panels.

I'm waiting with you for your report of over 100 kwh in a day, which would be a major milestone. My 5.4 addition should allow me to get close to that, but since about a 48 kwh day is the max for the 6.5 I now have, I'll look for about 85 kwh to be the future max.


----------



## JP11

I haven't really done the math.. but I'm just guessing.  I'm maxing out the inverters now.  10.1  it's two 5k inverters.  They run on max for around 4 hours.  I'm guessing that with 3 more hours of sunlight on the way by longest day.... I Think I'll make it.

Google says 22 percent of our power from hydro in Maine.  Not sure they'll be able to USE all of this snowpack.  I think there will be a lot of floodgates open.

I'm just looking around online now.  See there's a pellet boiler with a stirling engine.  5kw output, plus 50k BTU of heat.  That would be really cool for the winter days to heat my barn.    It never ends.

here's a few days ago.  I think there's a tree there to cut on the SW side.  You can see the hitch in the late afternoon.


----------



## jebatty

Nice curve! I've notice only once that my micro-inverters were clipping. Although rated at 250w each, they regularly will output into the low 260w range.

A graphic for all of March 2015.


----------



## JP11

is the blue bar average, or PVWatts average?


----------



## jebatty

Blue is PVWatts estimate for month daily average.


----------



## JP11

I'm still monkeying with my data collection.  With not a whole year in, the data kind of stinks.

JP


----------



## jebatty

On April 9, 2015, installation of 20 additional 270w panels (5.4kw total) was finished and turned "on." My installer says that I have understated the rating of my prior system at 6.5kw and it should be 6.89kw (26 x 265w panels). I had rated the system at the micro-inverter rating (250w/panel). The 270w panels also are using 250w micro-inverters. Total system now is 12.29kw at the panel rating and 11.5kw at the micro-inverter rating.



And the first full day of production, after a cloudy start with rapid clearing.


----------



## JP11

Nice curve.  You're going to have to combine the data on your own?  No.. must be same micro inverter company.. because I see 11kwh output there.

Congrats.  What happens in MN with your overage?  I can't remember.


----------



## woodgeek

since the fraction of time clipped by the inverters is small, the 'harvest' is more likely to correspond to the panel rating times annual resource.


----------



## JP11

Just realized we both have 48 panel systems.  Mine are rated at 255.  The inverters max out about 5060 each though.  Got covered in snow.. AGAIN a few days ago.  It's putting out 1kw.. but supposed to be real warm today.  I'm traveling this week.. but can check in on the array online.

JP


----------



## jebatty

> What happens in MN with your overage? I can't remember.


Currently the overage is a bill credit applied against future bills, with the overage $ paid out on request. A bill has been introduced in the MN legislator which will only allow credit in kwh against future bills, unused credits cancelled at the end of the year, and no compensation paid. Thus, the utility gets the power for free which it resells -- I call that stealing. I will be actively opposing the legislation, and I would be surprised if it passes.



> since the fraction of time clipped by the inverters is small, the 'harvest' is more likely to correspond to the panel rating times annual resource.


Exactly what the installer said, and I fully agree.


----------



## jebatty

> Just realized we both have 48 panel systems.


Close - I have 46!


----------



## JP11

Do you expect true overages? I'm not sure if I will.  I reduced consumption with circulators, and will reduce more over time with changeover to LEDs.  I will be adding another central air unit.  Worst case.. I put my parents bill into my name, and I can send KWH over to that bill.


----------



## jebatty

The original system produced 9MW the first 12 month period. I expect the addition to produce about 7.75MW. Typical annual usage is 12MW. My system is on the house meter, and I have two other meters. Those meters would more than use up the overagel I don't know yet whether the utility or the law will permit combining meters of a single customer. If, so no issue for me, but I still will oppose the bill.


----------



## JP11

Worth a phone call.  I had never seen the 'send the power to another account you have' in writing, but a guy from the power company told me I could do it.  I haven't tried yet.  I'm about 1 year from potentially having any credits 'expire'  and probably it wouldn't even be an issue then. (they always use oldest credits first)  I'll wait and see if I have as poor a production next winter as this one.  PVWatts said I'd make 800 in the winter months.. and I made NONE.  

I would for sure oppose the bill If I were you.  There's a proposed very large plant in coastal maine.  9 million dollar investment.  They are pushing for long term supply contract and some sort of green credits. Not sure if that will benefit me as an individual producer.  I should look into it.

JP


----------



## CaptSpiff

It is amazing how the "laws" differ in each state, and more importantly how they can change with the wind. I really think even "Net Metering" is not a certainty in this crazy rapidly changing solar PV landscape. The fight will definitely be won in the state capitals.


----------



## jebatty

I think I had a bit o' the Irish luck with the sun yesterday. Near perfect day, although the sky seemed hazy and the temps were in the 60's -- 80.94 kwh.


----------



## JP11

I made it.  Perfect solar day 78.79.  I don't think I'm getting clipped much more than a few KWh


----------



## CombatChris

How much better could either of these awesome setups preform with a sun-tracking setup where the panels move throughout the day? I know they're expensive as hell though...


----------



## jebatty

JP, that's what you've been waiting for and more to come. What a great day you had!


----------



## JP11

You too.  just realized.. this thread title doesn't really work for you anymore.


----------



## begreen

I'm going to try manual tracking for the pole mount this year. Will be turning it SW this week to reduce midday clipping and extend solar gain period.


----------



## jebatty

begreen or anyone: is it possible to edit the title from what this thread now is to something like "
Solar Electric - 6.5 kw system Expanded to 12.3 kw "?


----------



## JP11

jebatty said:


> JP, that's what you've been waiting for and more to come. What a great day you had!



Mirror image today.  within 500 watts of yesterday.  Sun is melting all the snowpack though.  I've got a moat across my driveway.  Culverts are frozen up.


----------



## jebatty

And we had practically no snow all winter, temps have been in the 60's, ice went out on the lake on April 11, two days later than the early ice-out record that anyone can remember, no rain yet this spring, nearby wetlands are nearly dry, and red flag forest/grass fire conditions.


----------



## jebatty

Thanks for the title change. 

In 2007 I bought and self-installed the Tarm Solo Plus 40 wood gasification boiler, and still today I remain amazed at the energy and efficiency in a well designed hydronic heating system using a gasifer. The energy in wood (a solid form of stored solar energy which is sustainable) is immense, using wood for space heating has saved us a lot of money, and our household is nearly completely free of fossil fuel sourced space heating (backup up only for electric heat and emergency on-electric LP space heater).

Then in October 2013 I had installed a 6.5kw solar PV system (26 - 265w panels), and my amazement multiplied. I still view in awe energy being generated, and lots of it, from doing nothing. The panels just sit there and make electricity. Being a ground mount, I am able to and do clear snow from the panels during the winter, so not quite do nothing. The effort is very minimal. 

When the 6.5 kw system was installed I had over-sized underground cabling installed which would have the capacity to handle the maximum power I could backfeed into the grid. And very glad that I did this. The 6.5 kw system performed so well that in early April 2015 I had installed another 5.4kw of PV (20 - 270w panels) to max the system. The posts on pages 11 and following detail some of the experience so far. More info will follow.


----------



## jebatty

A few quick reasons why I was motivated to install PV:

1) To do the "right thing." The results to date:


2) Simple rate of return (current annual $ value of electricity produced / cost of system) was 4.5-5%.
3) Had cash available that was earning much less than simple rate of return.
4) Retired and PV was a way to eliminate/reduce a monthly expense and hedge against rising electric rates.


----------



## jebatty

What is the payback on PV? Much discussed, but here's my summary take on this topic. Payback depends on lots of variable and projections into the future; therefore, lots of assumptions. This pun is intended: not easy to see through the clouds to predict the future, but a future where renewable energy of various sorts likely will play an increasingly larger role in electricity generation. History is far more certain. 

My initial 6.5kw system (now re-rated to 6.89kw) produced 9MW of electricity in year one. At my local kwh utility rate, that had a value of $1,035. The system was designed by a consultant and installed by a local electrician. The only work I did was setting up the controller for the panel microinverters. In round numbers the cost of the system was $32,000, and after the federal tax credit (no other incentives/rebates available) the cost was $22,400. Cost per watt of rating was $4.64 of total cost and $3.25 of net cost. My system was more expensive than most due to ground mounts and location a little more than 200 feet from the meter connection with required underground wiring, including boring under a public road. 

The return on investment in Year One was 3.2% on the total cost and 4.6% on the net cost. Year One maintenance/repair cost was $0. The only effort I expended was clearing snow off the panels, about 10 minutes per snow event. 

Is "payback" the right question to ask? In my perspective, it might be but also might not be. PV does return real dollars every year. It's projected lifespan is 25+ years, future maintenance/replacement of microinverters is possible, and in place systems have been in operation longer than 25 years. It is highly probable that PV will ultimately pay for itself and provide a return in excess of investment. Therefore, PV is not an item of consumption but is a real investment. My calculation based on various assumptions is that economic payback will occur somewhere in the period of Years 17-19.

The dollars paid for the PV could have been invested in CD's, at around 1% rate of return, in the stock market with a very good return in 2014 but in another year could have produced a large loss, or in a variety of other "investments" that provide an economic return: education, for example.

Or, the dollars could have been used to fuel consumption: a new car or truck, a fancy vacation, the local casino, and the list continues. None of these would have produced an economic return, each would have been a depreciating "asset" or fully consumed in a year, and most would have involved additional costs to be able to use the "asset." In other words, the consumption route ends up with nothing left over except perhaps the enjoyment which comes from spending the money, which is not a bad outcome.

Which is the better outcome? Personal preferences rule here. For me, a financial conservative, retired and on fixed income, spending this money to reduce future expenses and not spending the money on unnecessary consumption ruled the day. My system likely will eliminate my electric bill for the rest of my life -- that has real value.


----------



## jebatty

Cost of install for the 5.4kw addition: $23,782, or $4.40/watt before the federal tax credit, $16,647 after the federal tax credit, or $3.08/watt. If the addition produces electricity at the same rate as the initial system, then the additional 5.4kw array will produce 7054 kwh of electricity valued at $811, and the simple rate of return will be 4.9% on the net cost.


----------



## woodgeek

You know I think PV is a better investment than a CD at 1%, and while the expected return is less than the market, the risk is lower, which makes it a sensible personal choice.

But, if the array has a lifetime of 25 years, then it has zero value at 25 years, and its depreciation must be included in a ROI calculation to compare to those other investment instruments.  You will not get your principal back.  On a linear depreciation schedule, depreciation costs you 4% per year, and your simple return is 1%, at least for the first 25 years.

IOW, after 25 years at current cash flow, you will have a pile of money a bit larger than your net cost, say (25*5%) = 125% of initial net investment, and a nominally zero-value array.  With the 1% CD, you will get 100% of your principal back + about 30% compounded gains.

I'd call it an inflation or energy inflation hedge.  Or a hobby.


----------



## jebatty

Actual longevity likely is far more than 25 years. The Suniva panels carry a 25 year warranty.

The 1% CD loses money every year due to inflation and taxes, has declining net present value, and there is no gain. 

Year One for CD at 1%: $22,400 x .01 = $240. Total value = $22,640. Combined federal and state income taxes on $240 at assumed 25% rate = $60. Net total value = $22,580. Discount at assumed average 3.5% inflation rate = $22,580 x 0.965 = $21,789.70 net present value at end of Year One.

Year One for PV: $1,035 real value returned through payment of electric utility bill. Amount of money in a 1% CD that would pay $1,035 (ignore tax on the interest) = $103,500. I submit that the $22,400 PV system has a value much greater than the price I paid because it produces a much higher rate of return than a CD investment. But assuming that the PV system only added $22,400 to the value of my house, after inflation that would be worth $21,616 + $1,035 returned through payment of electric charges = $22,651 at the end of year one, $861 greater than the CD investment.


----------



## JP11

Wow, you're costs were really up there.  I was just under 35 for my 12kw roof mount.  very little wire to get down off the roof to inverter, and barn supply where it ties in. Prior to 10+ back on federal grant.

I think the bigger 'unknown' is the net metering laws.  It has, and will continue to be a battle.  The laws could change our ROI in a huge way.  They go more green and we could be getting paid better than market rate.  They start paying us wholesale during the day, and we buy back retail at night.. that's gonna hurt!

With the system paid for.... I just feel like all i've done is get rid of my power bill.  That's pretty cool in and of itself.  However.. it will be another 9 years or so before I'm truly in 'the black'

JP


----------



## woodgeek

jebatty said:


> Actual longevity likely is far more than 25 years. The Suniva panels carry a 25 year warranty.
> 
> The 1% CD loses money every year due to inflation and taxes, has declining net present value, and there is no gain.
> 
> Year One for CD at 1%: $22,400 x .01 = $240. Total value = $22,640. Combined federal and state income taxes on $240 at assumed 25% rate = $60. Net total value = $22,580. Discount at assumed average 3.5% inflation rate = $22,580 x 0.965 = $21,789.70 net present value at end of Year One.
> 
> Year One for PV: $1,035 real value returned through payment of electric utility bill. Amount of money in a 1% CD that would pay $1,035 (ignore tax on the interest) = $103,500. I submit that the $22,400 PV system has a value much greater than the price I paid because it produces a much higher rate of return than a CD investment. But assuming that the PV system only added $22,400 to the value of my house, after inflation that would be worth $21,616 + $1,035 returned through payment of electric charges = $22,651 at the end of year one, $861 greater than the CD investment.



I don't feel like trolling your thread (again ).  But inflation is 2%, CDs that pay 1% don't have a 25 year term (giving you flexibility in the future).  Just that it is disengenuous to keep citing a 5% risk free return when you neglect both (1) maintenance and depreciation and (2) risk that funding for net metering might change in the future.


----------



## jebatty

> I don't feel like trolling your thread (again )....


We agree far more than we where we have differences of opinion. My example was for Year One because that's where we are right now. In my prior thread Payback, I set forth the assumptions on which the 5% rate of return was based over the long term. Depreciation certainly is a factor. I did include a 0.5% derate per year. PV systems have been installed for far more than 25 years. Your guess is as good as mine on what a depreciation period should be. I won't live to see the first 25 years end. As to maintenance, it will be wait and see. After 1-1/2 years there has been none and no indication of when or what maintenance may be needed. The microinverters are warranted for 10 years, Wiring may be impacted over time, but all of the wiring is behind the panels, generally free from sun and most weather caused degradation. My racking is commercial grade, very heavy duty. If you have maintenance info on other high quality systems, I would be interested in seeing that.

There certainly are risks. I just see currently that the risks are very minimal, probably much less than the myriad of other risks we face on this planet Earth.


----------



## jebatty

Earth Day 2015, April 22, made history with my 12.3kw PV system. How appropriate. Production hit 88.93 kwh, and that included a few morning clouds. Peak production was 11,839 watts. When I run the ratios, April 22 out-performed the best comparative performance for my system before expansion. I did not see any clipping of the panels. The best day ever (March 15, 2014) for the 6.95kw array was 48 kwh. That means an equivalent best performance for the 5.4kw array should have been 37kw, for a total of 85 kwh. The clear sky forecast for today has the potential of doing as well, or maybe better?


----------



## JP11

Any idea on the few 'hitches' in the morning?  a small bit of shading maybe?


----------



## jebatty

A couple of small denser clouds and then some wispy larger clouds moved through.


----------



## begreen

I set the pole panel to face SW. That has extended my afternoon gains, but there's still some tree shadowing around 5pm that should go away soon as the sun's arc rises. Also getting mid-day clipping, but I think that overcapacity is balanced out by hazy and cloudy day gains.


----------



## jebatty

April 2015 likely will rank as one of the best PV months: 1.57MWh of production (actual was about 30kwh higher due to a data logger malfunction which did not record full production on one day). The 5.4kw addition went active late afternoon on April 9, so beginning with April 10 daily production included the 5.4kw addition.


----------



## begreen

Impressive. We are seeing very nice output now with a lot less tree shading, but on a more modest scale.


----------



## jebatty

May 19 tied my record for kwh daily production: 89kwh. Maximum output was 11,394 watts. What I haven't seen this year compared to last year, although I haven't been watching momentary output very much, is panel output above 265W/panel. April 22 also produced 89kwh, with maximum output at 11,839 watts.


*

*


----------



## JP11

Nice.  My peak so far is 85.2  Days are still getting longer though.  I imagine the few kw difference between us is just my clipping at 10.8kw from the inverters.

JP


----------



## jebatty

I think my panels already are using almost all the sun that is available, and longer days don't add much to daily production anymore. With south facing panels, sun both comes up east and sets west of the panels, little early morning and late afternoon production. Panels that could be rotated would do well in the long summer day environment. I'm fortunate to have minimal to no shading from 90 to 270 degrees, but shading of low sun would be quite severe as the sun rises and sets north of due east and west.


----------



## moey

I read this and all that came to mind was Id be mining virtual currencies with all that electricity. Forget giving it back to the power company. Although that may not be a sound idea I have not run numbers on such a endeavor.


----------



## jebatty

First full month of the 12.3kw PV system. Rain in May has replaced April showers. Seven days of above 80kwh (89kwh was the highest day) showed the power of the sun with clear skies and still cool temperatures. With the very dry Fall, Winter and Spring through April in our area, May showers were welcome. No glitches, no maintenance, and many kwh's banked to cover Fall and Winter under net metering.


----------



## jebatty

There is not much new happening, or likely to be happening, with my PV system -- just producing lots of electricity while I sit on the porch, enjoying a beverage, watching the kwh's flow, and once a month opening my electric bill and seeing nothing owing.

Unless there is continuing interest in monthly reports, I will let this thread rest in peace. 

Thanks to all who have followed my adventure, and best wishes to everyone whether or not you choose to move forward with clean energy.


----------



## maple1

I've got one.

Does the $ from the PV you generate get counted against only the power you consume - or does it also get counted against your base rate? e.g. here, I would have to pay $10.83/mo, even if I used zero electricity. So do you still have to pay that base rate since you still have a meter hooked up - even though you might be making more juice than you're using or even enough more to cover the base rate?


----------



## jebatty

The PV kwh are credited in $ against my bill, not just against kwh. Therefore, PV kwh in excess of utility supplied kwh also pay the base rate, currently $16.00/mo.


----------



## JP11

I was going to ask about your 'zero bill' comment. You really have no payment due?  My minimum bill is 10.65  Two months in a row now.


----------



## moey

JP11 said:


> I was going to ask about your 'zero bill' comment. You really have no payment due?  My minimum bill is 10.65  Two months in a row now.



Welcome to Maine...


----------



## peakbagger

I think Maine has the same setup as NH. I get a monthly $12.50  fee for the privilege of being hooked to the grid called the transmission and distribution fee. I consider it as what I pay for them to be my seasonal battery. My NH SREC payment just about covers it.

A lot of utilities are pushing to get fees hooked to the T&D charge so that solar folks with net metering have to pay more. At one point CMP was trying to get a higher flat rate for T&D that didn't vary by use. I dont think it went anywhere.


----------



## JP11

You really cannot complain much.  Never mind the capital outlay for a battery (and no affordable battery in the world will take in the power all summer, and let you use it in the winter)

For 10 bucks a month, you couldn't maintain a battery system (just MTX and saving up for cell replacement)

Solar producers in Maine.. FOR NOW are doing ok with this setup.  I'm sure it's a fight that's going to come up again.  

JP


----------



## jebatty

> I was going to ask about your 'zero bill' comment. You really have no payment due? My minimum bill is 10.65 Two months in a row now.


 The utility pays me $0.109/kwh for all power dumped into the grid. If I dumped 500kwh, I would get a credit on my bill of $54.50. That is applied against kwh I buy from the utility at $0.109/kwh, and any excess credit is applied against the base charge, currently $16.00/month. The utility has advised me that at any time I may request payment of the excess credits on my bill. 

There was a move in the legislature to changed the law to provide only a kwh credit, not a dollar credit, and to cancel excess kwh credits at the end of the year. It passed in the Republican controlled house but failed in the Democrat controlled Senate. The bill the Republican's passed also attempted to roll back or eliminate many other energy initiatives favoring alternative energy sources now part of MN law.


----------



## JP11

Good for you. I only get credit.  I think MA gets a plain old check back every month.  My credits expire after 12 months. Oldest credits are always used first.  We'll see in a year or so if I have any summer credits I don't need.  I can put another home (that my parents live in) in my name and sent a thousand KWH to that bill.  I'll never 'lose' any as long as I pay attention.


----------



## CaptSpiff

jebatty said:


> The utility pays me $0.109/kwh for all power dumped into the grid. If I dumped 500kwh, I would get a credit on my bill of $54.50. That is applied against kwh I buy from the utility at $0.109/kwh, and any excess credit is applied against the base charge, currently $16.00/month. The utility has advised me that at any time I may request payment of the excess credits on my bill.
> 
> There was a move in the legislature to changed the law to provide only a kwh credit, not a dollar credit, and to cancel excess kwh credits at the end of the year. It passed in the Republican controlled house but failed in the Democrat controlled Senate. The bill the Republican's passed also attempted to roll back or eliminate many other energy initiatives favoring alternative energy sources now part of MN law.



J, thanks for starting this thread and having the gumption to continue updating us for the past two years. I enjoyed it and learned a boat load!

Your second paragraph reveals a bit of the risk of looking at this PV as a simple investment. The laws of Net Metering, et al, are relatively new and implemented by legislatures in response to policy initiatives. The goals of state governments to reach 15, 20, 30% renewable energy levels in 10-20 years have brought "legislated opportunities" for us, but they could be undone at anytime in part or in whole. The greatest whispering I hear is the significant loss of tax revenue as the Utilities' cash registers (the home meter) ring less and less. There are big players involved and us pebbles will have to be pretty vocal to have a vote on when the avalanche starts.

In the mean time I continue to watch the PV installed price per Kw fall, and hope the laws & incentives continue to favor, as I'm still about a year from taking the plunge.


----------



## jebatty

I received the electric bill for May 8 - June 8. Total due was $0, and credits accumulate to apply against future bills.


----------



## begreen

Well done. Looks like you have a lot of sunshine in the bank for winter.


----------



## jebatty

Hard to resist! June was a very good month.


----------



## JP11

You got me beat.  I still have one lazy inverter that hasn't reported the last couple days (it will eventually send the data, and catch up the old. May was 1930.  June will come in around 1700.  Think I've got 1900 banked with the utility.  It's nice to just let the new central air in the house run!


----------



## Jeepman401

jebatty said:


> The utility pays me $0.109/kwh for all power dumped into the grid. If I dumped 500kwh, I would get a credit on my bill of $54.50. That is applied against kwh I buy from the utility at $0.109/kwh, and any excess credit is applied against the base charge, currently $16.00/month. The utility has advised me that at any time I may request payment of the excess credits on my bill.
> 
> There was a move in the legislature to changed the law to provide only a kwh credit, not a dollar credit, and to cancel excess kwh credits at the end of the year. It passed in the Republican controlled house but failed in the Democrat controlled Senate. The bill the Republican's passed also attempted to roll back or eliminate many other energy initiatives favoring alternative energy sources now part of MN law.



Seems that law passed in the last minute dealings of the special session. I have my system up and passed State inspection last week. The utility didn't pass me this morning because of the disconnect switch wasn't the type they wanted. They want a pull-out type and we used a breaker type switch, like a pool pump. Now I have to wait for the contractor next week, the State inspector again then the Utility. Very frustrated over a switch...the system works fine and meets the new Rapid Shutdown requirements. I hear in the commission meetings they are already talking about a new "backup" fee for solar and wind in town. Sad part is my system is the first in town and they are already talking of a new fee.


----------



## CaptSpiff

Jeepman401 said:


> Seems that law passed in the last minute dealings of the special session. I have my system up and passed State inspection last week. The utility didn't pass me this morning because of the disconnect switch wasn't the type they wanted. They want a pull-out type and we used a breaker type switch, like a pool pump. Now I have to wait for the contractor next week, the State inspector again then the Utility. Very frustrated over a switch...the system works fine and meets the new Rapid Shutdown requirements...


Your Utility requires a "visible break" so a disconnection can be visibly verified. An enclosed switch or circuit breaker does not offer that. That is quite common and I'm surprised your contractor did not check for that with a simple phone call. I hope he is not charging you for the callback.


----------



## begreen

Our utility wanted clearly labeled, separate visible disconnects for the system. These are external knife switches. They sent out diagrams and specs that called out this clearly when the system was approved for installation. Did your power company do this?


----------



## begreen

jebatty said:


> Hard to resist! June was a very good month.
> View attachment 159286


Good month for us too. We just had an extraordinarily sunny June, hitting max output on the inverter (4.5Kw) almost daily.


----------



## Jeepman401

begreen said:


> Our utility wanted clearly labeled, separate visible disconnects for the system. These are external knife switches. They sent out diagrams and specs that called out this clearly when the system was approved for installation. Did your power company do this?



Well, all is well now. Got a new pull-out disconnect installed and the gave me the go ahead. Officially up and running. This was totally new to everyone, me, the Utility and contractor so a few mistakes where made. The city had nothing in the code. I would guess should anyone else go solar in town, it will go smoother for them. The Utility needed to rewrite their interconnection and there is a city council meeting Monday to set the rate and take public comments. Pretty proud to become the first one here.


----------



## begreen

Well done, congratulations.


----------



## jebatty

Jeepman, a real accomplishment for you. Keep us informed. My utility, a co-op, did not require a pull-out disconnect. But I needed a breaker type disconnect both at the panels and at the interconnection point at the house so the system can be shut down at either location.

The law changes made during the 2015 Special Session are in Minn. Stat. 216B.164, Subd. 3. The changes became effective July 1, 2015, and apply only to systems net metered after that date. One of the changes allows the a municipal or co-op utility to add an additional fee to net metered service. I hope your utility did not delay the net metered connection to take advantage of the ability to collect this extra fee.


> A cooperative electric association or municipal utility may charge an additional fee to recover the fixed costs not already paid for by the customer through the customer's existing billing arrangement. Any additional charge by the utility must be reasonable and appropriate for that class of customer based on the most recent cost of service study. The cost of service study must be made available for review by a customer of the utility upon request.


Another change allows the customer to elect net meter compensation either at the "average retail rate" or by kwh credit. If by kwh credit: 





> ... [the customer] may elect to be compensated for the customer's net input into the utility system in the form of a kilowatt-hour credit on the customer's energy bill carried forward and applied to subsequent energy bills. Any kilowatt-hour credits carried forward by the customer cancel at the end of the calendar year with no additional compensation.


The "average retail rate" provision states 





> ... [the customer] may elect that the compensation for net input by the qualifying facility into the utility system shall be at the average retail utility energy rate. "Average retail utility energy rate" is defined as the average of the retail energy rates, exclusive of special rates based on income, age, or energy conservation, according to the applicable rate schedule of the utility for sales to that class of customer.


Your municipal utility's rate structure would have to be known to make the best meter compensation election, and although this does not apply to me because my system was installed before July 1, 2015, I think the "average retail rate" election, which I now have, provides the best result for me.


----------



## jebatty

Jeepman, how about some pictures?


----------



## Jeepman401

You know that is my fear, they delayed it to get me under the new law. My sales man fought their $5000 application fee and got them to drop it to $1000 fee...which I paid to get the project going. He then scolded them threw e-mails for even that amount saying it was way higher than anywhere else in MN. 

Ultimately they said they would refund $520 at the end. But when we had it inspected by the State the contractor invited the Utility but they declined. The State inspectors wanted a few more labels and came back and passed it on the 26th of June. In the paper work I got from the Utility outlining the public hearings etc they noted the 29th of June as their inspection date. They delayed it until the 1st which I told them I wasn't happy with and would rather do it the 29th. They said they had lined it up for the 1st. 

Well, then with their change with the switch they got it delayed until the 2nd of July as the commissioned dated. Other interconnection papers are signed earlier in May. Being the first in town I can't see them wanting to add a fee to the only guy, but then again....I will be very upset and may take it to Court, news etc if they ever try to add a "backup" fee to me. 

They have a city council meeting on the 6th to approve the rate they pay me, that I am thinking of going to and and bringing up these issue's... But I don't want to sound paranoid either, it just looks really fishy to me.

I'm writing a separate thread with pics for everyone and will post it soon.


----------



## begreen

That was the nice thing about our inspection. No middlemen and no local govt. controls. Everything was decided on the state level, the PUC and the power company. Instructions and protocols were clear and easy to follow.


----------



## Jeepman401

begreen said:


> That was the nice thing about our inspection. No middlemen and no local govt. controls. Everything was decided on the state level, the PUC and the power company. Instructions and protocols were clear and easy to follow.



I had two State inspectors come by at the same time, one just had a class on new labeling and systems. When the Utility showed up the brought 11 people, all their electrical guys and linemen. Why wouldn't the Utility come when the State inspectors and contractor would be their to voice concerns/corrections/questions if it was a first for them??
If the switch was wrong, now the State inspectors won't know and just approve other projects that don't meet the Utility requirements. Seems counterproductive on the Utilitys part...unless they where purposely delaying.


----------



## jebatty

I may have said this before. My co-op utility charged a fee of $100. The electrical inspector came before and passed the installation before the utility inspection. All the utility checked were the disconnects at the panels and at the house, the voltage, and the 60 cps. My electrician had installed a number of other systems under the same utility, and my system was designed by a consultant who also had designed several other local systems, so I assume that the utility was very comfortable with the work of the electrician and of the consultant. 

At this time I understand that there are about 30 active PV systems with my utility. I am advised that there is no current plan to charge an extra fee, and I have asked to be advised if and when that comes under consideration and to have an opportunity to be involved before a fee is to be added.


----------



## begreen

Does the local electrician's union help at all? Here they kicked in $500 which more than covered all fees.


----------



## Jeepman401

begreen said:


> Does the local electrician's union help at all? Here they kicked in $500 which more than covered all fees.


? Explain please....interested in your experience. Never heard of anything like this. State or local area specific maybe?


----------



## begreen

The $500 IBEW local 46 rebate was part of the proposal. We got it for each installation. If your electrician is union ask them to investigate.

http://artisanelectricinc.com/solar/incentives-and-subsidies/


----------



## jebatty

After looking back over utility bills, the last electric bill I had to pay was for the period ending March 3, 2014, 16 months ago. Since then the PV system has provided credits which have paid the electric bill in full, and credits continue to accumulate to cover bills during the low PV production months of Nov - Feb. Based on past experience, I expect March to be a net credit month, as it was in Mar 2014 and 2015.


----------



## jebatty

Some graphic information which demonstrates how cool, clear spring days can out produce hot, clear summer days. July 23 was the first dawn to dusk clear day of this summer and the PV produced 75.34 kwh. First production recorded at 6:30am and final production at 8:15pm. Maximum production was 9,660 watts. Day low-high temperature was 62-85F.




April 22 is my highest, single day production record, 88.93kwh. Also a dawn to dusk clear day (the blips in the chart are from a couple of distant trees). First production recorded at 6:45am and final production at 7:45pm. Maximum production was 11,839 watts. Day low-high temperature was 26-41F.


The cooler air of winter/spring seems to be more free of dust and humidity than summer air, and the cooler temp means less electrical resistance in the panels and wiring. Summer air seems to have more dust and humidity, and this year particularly smoke from distant forest fires, along with higher temps.

The net result, summer maximum daily production was 85% of winter/spring maximum daily production. Can't help but like clear winter/spring days.


----------



## jebatty

An update on this summer's performance. There were no system problems/maintenance of any kind during this period. I have substantial credits accumulated which will offset the cost of needed supplemental winter electric heat.

Number of days of production over 60kwh:
Jun - 16
Jul - 14
Aug - 5
Sep - 11

The 26 panel array went active at the end of October 2013. During its first year it produced 9007kwh of electricity. At the end of this month I will be able to compare Year 1 and Year 2 production. As of today, with 16 days yet to go in the month, the 26 panel array has produced 8681kwh of electricity.


----------



## jebatty

Recalling the Tesla Powerwall battery proposal, about 10kwh/day average battery capacity is about what my household would need to go off-grid in the summer with little change in lifestyle. I know we also could manage our power better to focus high electrical demand (electric clothes dryer, stove and oven) during sunny daytime production periods. Extremely cloudy days were few. Days with less than 20 kwh production during Jun-Sept period: Jun - 0; Jul - 0; Aug - 4; Sep - 2. Even these days would have produced enough daytime power for uses other than the electric dryer and some cooking.

The main difference in electric demand between summer and other periods during the year likely is lighting and electric heat. Our lighting now is virtually 100% LED, so lighting impact probably is small. Electric supplemental heat is not small. Most of that heat goes into our basement, and an electric storage unit could be used to absorb excess daytime production and provide that heat as needed. Needed would be a control that could sense excess PV and switch the storage unit into the absorb mode when excess PV was available. 

Also, since I now have a grid-tied microinverter system, a control to "fool" the microinverters into sensing available grid power would be needed to keep the system operating off-grid. I think that type of control already may be available or soon will be.


----------



## jebatty

I just wrapped up year two on the original 6.5kw (actually 6.9kw) solar PV system, the year being November 1 - October 31. Not saying that 2 years makes a long term average, but I’m a little amazed at how close the two years came out in energy production.

Year One (Nov 1, 2013 - Oct 31, 2014) – AC power produced at the array: 8,992 Kwh (which I corrected from 9,007 previously reported and then rounded to 9,000 Kwh or 9MWh in prior posts).

Year Two (Nov 1, 2015 - Oct 31, 2015) – AC power produced at the array: 8,979 Kwh, a difference of -13 kwh from 2014. This difference is roughly the same as one sunny vs one cloudy day.

FWIW, the ratio of AC power produced at the array to DC power rating of the array was 1.3: 9000 AC Kwh produced / 6900 DC Wh rating.

I experience a 1.2% line loss from AC power at the array as measured by the AC production meter at the interconnection point at our house, a distance of about 220 feet from the array. The line loss increased to 1.2% from 0.9% after I added the 5.4kw array in April 2015. The explanation likely is the additional resistance resulting from higher amperage flowing through the underground supply cable.             

The value of 9,000 Kwh produced by the 6.9kw array, as reduced by the line loss, was approximately $1,026 based on our electric rate. Our rate varies somewhat month to month based on the cost of wholesale electric purchased by the utility.

On April 9, 2015, I added a 5.4kw array, so it will be a few months until the combined annual performance of the now 12.3kw system can be reported.

The final observation remains the same as at the end of Year One – very satisfied with the PV and look forward to future dividends for self and community.


----------



## begreen

jebatty said:


> Also, since I now have a grid-tied microinverter system, a control to "fool" the microinverters into sensing available grid power would be needed to keep the system operating off-grid. I think that type of control already may be available or soon will be.


Well done on the extended capacity.  About that control... really?


----------



## jebatty

An article in Home Power, "AC-Coupling," July-August 2015, pages 38-43, discusses this topic. I am inferring (assuming) that progress on AC coupled systems will continue, and the time will come when a grid-tied, microinverter system such as mine can use the solar PV even when the grid goes down, along with battery supplemental/backup power when PV power is insufficient. Supplemental power via a battery along the Tesla PowerWall concept is a future I can foresee.


----------



## bdud

Interesting what you where saying about winter/spring days producing a decent amount of electricity. I had a 25 panel system installed late May this year and since October I have been seeing the effects of shading from some trees, some mine. I am curious whether it will be worthwhile having the trees removed that are mine. Here is my output from today. 
	

		
			
		

		
	



Thoughts?


----------



## jebatty

Worthwhile to remove trees? Yes, no, maybe. Reducing shading will increase production Are all the dips in production the result of shading? You can sample days with no cloud or other shading except trees. Then interpolate (round out) your curve to represent what production would have been if no shading, Average all of your data points to get kwh with the interpolated curve, compare that to your actual kwh with shading, and that will give you a pretty good approximation of the maximum possible production. Then decide what trees could come down and what impact that may have. Determine a $ value of increased kwh vs "value" of retained trees. That may help guide a decision.


----------



## bdud

The dips in output are just from the shading from the trees. It got worse as the sun drops lower, not a problem during the summer, this is a picture from the end of September.
The shading seems to be moving to later in the day. 
Any idea how many months I can expect the sun be this low?


----------



## jebatty

Check out suncalc.net and http://www.solartopo.com/solar-orbit.htm. For my area, the sun reaches its lowest point at 19 degrees above the horizon. I have very minimal shading, and that impacts about 6 weeks on both sides of December 22 (winter solstice). I have estimated on an annual basis about 4% loss of production due to tree shading.

If you are getting this shading right now, expect that to continue until about the same time after the winter solstice.


----------



## bdud

Thank you. Going by those websites, I should be back to full sun early March. 
Going to your earlier post that April 22nd was your highest single day production, what is the rough percentage of average monthly output. i.e. July 100%, August 98%, December 85%?
I am trying to understand how much I would miss out during the worst "dark" winter solstice time.
I don't think my house roof is getting any taller but I am sure those pine trees are still growing.


----------



## jebatty

My PV software provides setting up a "budget" of estimated monthly production. I used PV Watts and then modified some of the parameter to come up with what I think should be a good estimate of annual production for my system. Below is my budget along with actual monthly production beginning with May 2015. I used May because that was the first full month of my expanded PV system rated at 12.3kw DC.

I arrived at my estimate based on two years experience with the original 6.9kw array which produced just under 9,000 kwh each year. If 6.9kw produces 9,000 kwh, then the additional 5.4kw array should produce a little more than 7,000 kwh (9000 x 5.4 / 6.9 = 7,043 and 9000 + 7000 = 16,000). I decided to "challenge" my system by adding 1,000 kwh to the annual estimate because I am an optimistic person, so my annual estimate is 17,000 kwh rather than 16,000 kwh.


----------



## bdud

Nice..
I put this sheet together with yours and my numbers..




Looking the percentages my numbers and output is delayed maybe by a month, i.e. my August to your July.
Guessed at an ideal 61% for November, your October, I need a 549 output, going by present readings I might get 443 or 49% of my max output month. On some Solar quotes, Sungevity predicted 175 and Solarflair said ~300. Maybe my output is not too bad.


----------



## jebatty

Now this is a shading problem. So far this November cloud cover has been so intense that system production has been less than 5 kWh for five days already, one day even being 0.98 kWh, and likely will continue at this low level at least today and tomorrow as well. From a daily high so far at 89 kWh to 0.98 kWh is some serious shading.


----------



## jebatty

An advantage to ground mount Solar PV - ease of clearing snow. An long-handled broom did the job.


----------



## jebatty

jebatty said:


> An advantage to ground mount Solar PV - ease of clearing snow. An long-handled broom did the job.


Forgot the pix.


----------



## begreen

Due to our location on a north slope and the low angle of the sun we are only getting a few hours of production a day at this time of year. Quite a difference from a few months ago.


----------



## jebatty

Have you used this site to see the sun zenith at your location? Type in the address and date.
http://www.solartopo.com/solar-orbit.htm

I have about a 6 week period before and after the winter solstice when I get shading from trees. On Nov 10 the sun zenith is 25.96 degrees, today (Nov 24) it is 22.57 degrees, and on Dec 22 it is 19.64 degrees. Similarly, Jan 22 - 23.16 degrees, and Feb 4 - 26.54 degrees. The shading is nearly all in the morning, until about 10:00 - 10:30am within this period. While there is shading, the sun angle is so low that the shading has little impact on daily production.


----------



## jebatty

Dec 2015 likely has been about the cloudiest month ever.




Total kwh for the month only 309.74 against a predicted average of 996 kwh.


----------



## begreen

We had 3 sunny days here in December. 2nd rainiest on record. I don't even look at our pathetic Dec. production. Being at high latitude on the north slope of the hill really puts the sun at a low angle. It gets clipped by tall trees most of the day. By February things will start looking brighter.


----------



## jebatty

A chart showing solar PV kwh production for 2015. Interesting is that kwh in Jan and Feb, which was only the 6.9kw system, were nearly the same as Nov and Dec, which now included the additional 5.3kw. Lots of very cloudy weather in Nov and Dec.

Also interesting in that April - Oct had monthly production in the range of 66% or better of July which was the highest production month. It is clear that on a broad geographic scale utilities/grid can depend on a high level of consistent and predictable solar PV kwh availability to meet high AC and other summer demands for power.


----------



## jebatty

Screaming PV on February 12, 2016. Clear sky, temperature +1F, on a 5 minute log, output nudged over 12,000 watts for three 5 minute intervals from 12:35pm to 12:45pm (12,040 - 12,130 - 12,040 watts). Since the system was expanded to 12.3kW on April 9, 2015, this is the first recorded production over 12,000 watts. With many more clear, cold days yet to come (hopefully, or not!), it will be interesting to see how high production will go. The initial system at 6.9kW actually briefly reaching output into the 6800 watt range. The microinverters carry a nominal rating of 6500 watts total, so they were exceeding their rated output on these occasions. I noticed clipping only once with the 6.9kW system.


----------



## begreen

Awesome. Are you getting gain from snow reflection too?

We are finally starting to see some decent output, but too brief. Our location and the low angle of the sun still make for a lot of shading issues in February.


----------



## jebatty

Gain from snow reflection for sure. Hard to measure exactly what that is. Finished theday at 70.1 kWh.


----------



## jebatty

February 29, leap year day, and PV mounted a stunning performance on a cold, cloudless day: 82.73 kWh. Peak output at 12,131 watts, and that's average panel output of 264 watts. Based on the flat top of the curve, I would say the microinverters maxed out and were clipping panel output. 26 of the panels are rated at 265 watts and 20 at 270 watts. The Aurora microinverters are rated at 250 watts nominal output, maximum output of 260 watts, and maximum usable power of 265 watts. Annual output is on schedule at 16MWh, with the first full year of the expanded system ending on April 9.

The all-time high daily output remains at 89 kWh which occurred on April 22, 2015. Maybe a surprise will be in store for this year with some more cold, clear days.


----------



## jebatty

A little more detail.


----------



## jebatty

April 1-4 has delivered awe inspiring sunny days and production for the four days totaled 315kWh, the high day being 86kWh. That four day total exceeded total December 2015 production of 310kWh, and is about 1/2 of the production of both November 2015 and January 2016, each at 673kWh.


----------



## jebatty

The first equipment failure occurred a few days ago: one micro-inverter failed (under warranty). The mfr is supplying a replacement. I only can guess at the reason, and that is that cloud cover was quite heavy, then a brief clearing of the clouds and a burst of sunlight, power output spiked high on the panel served by the micro, and the micro failed. The micro has been in service 2-1/2 years. This type of sunburst is not unusual, it has happened many times before, and I hope that future such failures do not occur.


----------



## peakbagger

What brand and model of microinverter?


----------



## begreen

One would think that transient spike protection would be built in to the design. Could just be a component failure. How much work will it be to replace this micro-inverter?


----------



## peakbagger

Since he has a rack mount in the photo, its probably pretty easy compared to a roof mount.

Microinverters have it tough, the ambient conditions are brutal and in order to be competitive they have to be inexpensive. Generally the solution is build them good enough to get the cash flowing and then deal with the warranty issues later. Enphase has replaced a boat load of the early 190 watt units but so far has survived to come out with hopefully better product.


----------



## begreen

I didn't go for Enphase on our arrays due to the limited lifetime of electrolytic capacitors. Have they changed this in their newer units?


----------



## peakbagger

Not sure, the newer ones just don't seem to be failing as quickly although I have seen reports of occasional failures.


----------



## jebatty

The microinverter is the ABB MICRO-0.25-I-OUTD, nominally rated at 250 watts. The last report from the micro before failure showed output at 222 watts. But a sunburst does produce a burst in panel output that can spike quite high before falling back to a full sun output scenario. The micros I have easily have output up to 265 watts before clipping is evident.

With the ground mount, and the micro that failed being on the bottom row of the array, replacement will be very easy. Maintenance and service, if needed, is a real plus with ground mount. I expect a replacement to arrive soon.

I haven't seen reports of other failures with the ABB micros, but I do not spend much time trying to track failures. ABB is a big company in the electric power industry.


----------



## peakbagger

Thanks, folks always ask me about micros. I have a lot more faith in ABB than Enphase.

Folks tend to get scared away from ground mounts or pole mounts. Yes they cost more up front but the option for installing at optimal seasonal angle or in the case of pole mounts having seasonal angle adjustment is big plus. I expect the environment for microinverters on the back of a ground mount is far less harsh than sitting between a shingle roof and a panel. Its a lot easier to clean off snow and I find the winter time extra irradiation from snow reflection boosts output compared to a roof mount.


----------



## begreen

We have one ground and one pole mounted array. Both feed into a PowerOne 2 channel inverter. The pole mount is angled to the SW. This helps lengthen the output time over the day. So far no issues except that one needs to be careful weedeating near a ground array. An errant pebble thrown by the weedeater can shatter the tempered glass. (don't ask how I know)


----------



## Where2

I've looked at the temperature graphs from my enphase M215 microinverters before. I just looked at the graphs of the past week from several of them just for curiosity. An inverter near the peak of the roof seems to hit 127°F in the middle of the output day. Inverters near the eave of the roof run 114°F on a similar day. Although technically hot, it's not the harsh environment hot I tend to expect of gear I specify to run mounted in a closed metal electronics cabinet in the blazing sun. I find it curious the peak temperature does not necessarily coincide with peak power output from my system. That may be due to my roof facet facing ~16° West of South.


----------



## jebatty

I received the warranty replacement micro and my PV installer electrician switched out the defective micro for the new one. Reprogramming the data collection devices, which I did, also was easy. What was a little tricky is that the micros store cumulative data and also transmit data to the ABB web portal, and some ABB tech guidance was needed to make sure that stored data related to the replaced micro was not lost. A quick phone call to ABB was very helpful on this.

The ABB MICRO-0.25-I-OUTD (250 watt) are no longer being made, higher output micros now are the norm. I did find a PV supplier who still had the 250 watt micros and I bought two for $100 each to keep on hand for backup replacement. Switching one out is not difficult.


----------



## peakbagger

Out of curiosity does the microinverter use the locking MC4 connectors that require the special tool?

Smart idea stocking up on couple spares. I have spare PV panel stashed away for my orphan Evergreens. Wish I had bought one for my other arrays but they are safe up on roof while the Evergreens are on a pole mount and far more accessible.


----------



## jebatty

peakbagger said:


> Out of curiosity does the microinverter use the locking MC4 connectors that require the special tool?


 Yes, but the special tool is a very simple device, easily bypassed with an even more simple homemade tool.


----------



## jebatty

May 2016 turned out to be a very good solar month, coming within a few kWh of my estimate of the system's average performance potential: total energy for the month was 1.81 kWh vs 1.82 kWh of potential estimated performance, just 18.73kWh short of meeting the estimate. One more sunny day during the month would have pushed production over the estimate. The blue bar is the estimated daily average performance for May (58.87kWh) and the green bar is actual performance. Maximum daily performance hovers right around 83-84kWh, about 6.75kWh per DC kW rating of the system (12.3kW).

There seems to always be something that results in less production than might be expected. In May (besides weather) it was smoke from forest fires in Alberta. Those fires may burn for a long time with a negative impact on irradiance in northern Minnesota. Other more "normal" negative factors can include increased clouds and rain events, higher than normal air temperatures, higher than normal humidity, and higher than normal dust blowing in from the Dakota's and western Minnesota.

Regardless, as of June 8, 2016, our utility bill already has an outstanding credit of nearly 3,700 kWh and during 2016 our electric bill should be fully off-set by solar PV credits. Most of the credits are consumed by kWh for supplemental electric heat during the winter.


----------



## jebatty

With Christmas nearly here, the PV system reminds me of the generous gift of the sun. Total energy to date: 38,222 kWh with a value of $5,708. Being just about at the shortest day of the year, and the sun rising only 19* above the horizon and nearly clear days, daily energy is still in the 30-34 kWh range.


----------



## begreen

I'm jealous. Here's what a low angle sun and north sloping property does to solar gain. And this was on a sunny day. High power consumption later in the day is Christmas baking projects.


----------



## JP11

Glad to see you're still going strong.  I'm 'ahead' of where I was this time last year.  I think it's 1000 Kwh or so ahead.  Should make a min bill (around 12 bucks a month now) all year.  Last year I had one month with a 55 dollar bill.

Merry Christmas

JP


----------



## jebatty

Mar 21, 2017, missed tying my single day record kWh production by 1 kWh: 88 kWh vs record of 89kWh. From 12:45pm - 2:00pm energy was over 12,000W. Peak was 12,120W. A stunning day.


----------



## TonyVideo

I think I have solar envy.

Sent from my SM-G930V using Tapatalk


----------



## jebatty

Here's a graph showing 4 years (2014-17) experience with my solar PV system.
Solar PV 2014-17


----------



## jebatty

91.23 kWh on April 7, 2018. I was beginning to think that after more than 4 years of operation, I would not again see a new daily high kWh production record, but April 7, 2018, did just that: 91.23 kWh AC output, "dwarfing" the prior record of 89 kWh. The high point for the day was 12,100 watts, for an a peak average of 263 watts/panel. 26 panels are 265W and 20 panels are 270W. Maximum daily production typically occurs during Mar-Apr on clear, cold days with full ground snow cover. The high on Apr 7 was 28F, and full ground snow cover continues in north-central Minnesota.


----------

