Solar electric 6.5kw expanded to 12.3kw

[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]

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]

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]

... 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]

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 (broken link removed to 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.