# OK, PV experts - fill webbie in......



## webbie (Nov 20, 2011)

I'm looking at these low PV prices - definitely tempting!

So, before I make all the mistakes everyone else is/has, can folks clue me in on some things?

1. My roof is about 210 degrees facing - just about SW exactly - and is 12/12 - 45 degrees. Am I just as well, in MA, installing directly on it? I need to roof mount due to high tree line.

2. These very low prices of $1 or so a watt - based on all available evidence, is this an anomaly or is the combo of excess capacity and new R&D likely to make prices stay low in the future?

3. Any Ma-certified installers out there who want to bid on something for me? Or, are there any co-ops or other group efforts in Western Ma or vicinity?

4. Given a budget of 6-10K out of pocket - after Federal and (if any) state credits, what size system should I be looking at? I may be limited by full sun roof space - I definitely have 250 sq feet or so.....so that may not be a limit?

5. One of my big interests is in a back-up when power fails, so I would want a small battery bank in addition to any (if any) grid tie. I may even be satisfied with no grid tie at all - that is, a smaller system which perhaps feeds a couple circuits that are always used (refrig, etc.).....and a backup circuit.....for power out (I can plug stuff into an inverter - I'm pretty handy with stuff)....

It's all so confusing. I'm thinking that sometimes it doesn't pay to go big - we don't have kids around the house so keep all the lights off, etc.....and are gone a lot of the time also, so maybe appropriate technology (smaller) is better? At the same time, if the larger system is free due to more tax credits - well, call me a welfare king!

Opinions?


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## begreen (Nov 20, 2011)

There is only one grid-tie - off grid combo that I know of and that is made by Sunny. (Sunny-Boy + Sunny Island) It's a slick system, the two inverters talk with one another and allow you to use both arrays when the power goes out, but it'll cost more than you are budgeting due to dual inverters + battery bank. You would need two arrays, one for grid and one for non-grid + battery (and they have a gen tie in). 

Here's a good place to start calculation and design:
http://www.builditsolar.com/

Sunny:
http://www.sma-america.com/en_US/home.html

And I just stumbled on a Dummies solar version:
http://www.dummies.com/how-to/content/the-essentials-of-planning-your-solar-power-system.html

Another good resource:
http://www.backwoodssolar.com/


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## webbie (Nov 20, 2011)

Thanks, BG.....so, on a typical grid-tie, what happens when the power goes out? Does it then simply feed a tiny bit of power into the main breaker box (or an assigned circuit or two)?

If nothing else, I'd want a small bank of batteries to provide a nice buffer so that at night or during cloudy periods, we still could pull a decent load...to, for instance, run the refrig for a couple hours.....

I'll do some research, but at first glance it appears that the economics favor either going big (getting all available credits, etc.) or going very small (just a battery charging and inverter system with less credits, but a good power outage back up).....but...question them becomes what are the exact specs for Fed 30% credit?

That is, would a system which is NOT grid tied, but did feed into some parts of the house and used the output continuously qualify? Or, it is grid tie or naught?


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## begreen (Nov 20, 2011)

The grid tie inverter is constantly checking for grid power. When there's an outage, it immediately shuts the inverter down. I am considering an independent off grid system that will just feed a few loads in the house, but one should understand that battery life and maintenance is not trivial or low cost.


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## Former Farmer (Nov 20, 2011)

Below is a link to PVWatts.  You can select your area, enter your azimuth, and roof angle.  This will give you an estimate of how much power per month an array can produce in your area.

http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/


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## webbie (Nov 20, 2011)

Former Farmer said:
			
		

> Below is a link to PVWatts.  You can select your area, enter your azimuth, and roof angle.  This will give you an estimate of how much power per month an array can produce in your area.
> 
> http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/



Well, according to that I am golden....except for some tall spindly tress behind that might partially shade (mostly just branch shading) from Nov to Feb.......I can definitely cut some of them though. 

That shows avg 4.37 KW, M2.....which is not too bad considering.


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## DBoon (Nov 22, 2011)

Check out www.dsireusa.org


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## mbcijim (Nov 22, 2011)

The ITC as a cash grant expires 12/31/11.  ITC is the federal 30% tax credit.  It will be reverting back to a true tax credit and not a cash grant.  This will make it harder for residential systems to get built.  If you pay $10,000 in taxes come April, it won't be an issue for you.  But if you're used to cash back then this may pose a problem as I am not sure the ITC can be used that way.  

You can extend the cash grant until 9/1/12 (check with a professional) by spending 5% of the cost before 12/31/11.


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## peakbagger (Nov 22, 2011)

Outback makes a slick battery backup grid tie unit. The typical battery bank is designed more for short events than for days at a time but with some load management its a nice option. Most states requires solar survey prior to getting a preliminary review ,but generally if you have zero shading from 9 am to 3 PM year round, you should be okay. A 12/12 pitch is pretty close to optimal for a fixed array. Even the shadow from a waste stack can knock out a lot of you production unless you go with microinverters, but there is a high front end cost for microinverters so its another trade off.

Budget in a new roof unless your roof is in excellent condition. Once the panels are on, you really dont want to take them down to do a roof. YOu cant deduct the roof as part of the installation cost.

As for cheap panels, there is currently a glut and they are being sold for less than the material costs in some cases. Just realize that most of the maunfacturers that are dumping panels may not be here in a few years so warranties will be worthless. Realistically unless the panels were built with a long term defect, if they work out of the box they are probably good for the long term. I would stick with either monocrystaline of polymorphous silcone versus some the the new type panels that use "CIGS" technology and would avoid the printed panels. Realize a solar panel sells for less than an Anderson window per square foot and they are a lot more complex than a window. At some point supply will meet demand and the prices will stop dropping.

With the 30% federal consumer rebate gone 12/31 (applies to systems installed on or before 12/31/2011), the demand the US will drop, like the wood stove business there will most likely be a major shake out of installers due to loss of incentives. Commercial installations have some tax benefits that continue for a while so you may think about doing this as part of a business. 

As there has been for 30 years, there are always a new break through technology announced that will justify delay. All I can say is that 99.9 % of these claims dont pan out, but what does steadilly increase is the cost for power. 

I believe your inquiry is about a Mass installation. Mass is currently a special case, the state has a renewable portfolio standard requiring a certain percentage renewable generation. The state recently effectively banned biomass power plants from counting as renewable which was the only relatively low cost renewable power they had. The lost capacity is going to have to be replaced with power like Cape Wind which is at least 30 cents per KW. Therefore the state is looking at a substantial increase in power costs which most likely will encourage incentives for small scale renewable. If they follow the Vermont example, VT is paying 31 cents per KW produced as a feed in tariff. This makes a roof mount somewhat less attractive as it cant be "tracked" to maximize solar gain as compared to the NH program where there is a fixed rebate for watts installed. The only potential disruption is canadian hydro, currently Mass does not accept Canadian Hydro as renewable. VT also had a similiar prohibition but revoked it with little publicity when they got to choose between "dirty" hydro or VT Yankee.  Hydro Quebec has been in the background for quite awhile trying to get the law changed and if it does, then the state may substantially cut back on the amount they pay for solar. 

I would rather get an upfront rebate from the state for installed watts rather than a feed in tariff but it all comes down to what you can get in rebates and incentives.


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## mbcijim (Nov 22, 2011)

Peakbagger has several good points. One being that solar installed in the name of a business is depreciable.  This year it's 100% of cost.  Next year it is 50%.  I suspect they will make it better.  They have for the last 3-4 years.


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## GaryGary (Nov 22, 2011)

Hi,
One thing not to overlook is to have a go at cutting your consumption first.  

We were initially at 1000 KWH a month, and got that down to 500 KWH a month with conservation projects.  This was relatively cheap -- about $1200.  The projects we did are listed here: http://www.builditsolar.com/References/Half/ProjectsConservation.htm 
The best set of projects for you may well be different, but you get the idea -- have a look at everything you have that uses electricity.  

We built a PV system in late 2009, so prices were a bit higher, but I did all the work myself and that saved quite a bit.  Anyway, the PV system is a 2.150 KW and on average saves us 250 KWH a month.  It cost $10K before rebates and about $6K after rebates.  Details here: http://www.builditsolar.com/Projects/PV/EnphasePV/Main.htm

SO -- bottom line:

- Conservation and efficiency: Saved 500 KWH a month at a cost of $1200

- Solar electric system:  Saved 250 KWH a month at a cost of $6000

Your millage may vary of course, but don't overlook conservation.

----
It sounds like you might be faced with partial shading, which can be bad for PV production.  If you can't eliminate the shading, I'd suggest you have a look at the micro inverter systems as they handle shading better: http://www.builditsolar.com/Projects/PV/EnphasePV/Shading.htm

Gary


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## peakbagger (Nov 22, 2011)

Self installed grid tied systems are most likely a thing of the past in any area that is under the latest NEC code. They now state that only qualified individuals may install, which most jurisdictions consider licensed.

Bummer as it was quite an educational process I went through to learn how to install. John Wiles reports were real handy.

By the way most of the credits and grants are for grid tied units only. NH is one of the few states that allow off grid residential systems to qualfiy.


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## webbie (Nov 22, 2011)

Hmmm.....I thought the 30% was until 2016 - perhaps it is.....that is, if I pay that much tax!

Jim, you can be assured that I fund the government to the tune of vastly more than I would be able to deduct, so I am golden there!

I have to do more looking at the site. The days are so short now that it seems to screw up the "solar day".......that is, the sun is headed down after about 2PM....fast! I notice the spot I picked out is sunny from about 8:30 am to 2PM now...with daylight savings time. I can cut some trees, though, and probably do better....shading is 100% tree based, and we have hundreds of acres of trees just growing wild in that direction, so no loss to lower the front row or two......

I've got an old solar chart - that you peer through - somewhere around from way back when. Hard to imagine that I actually has a business in 1979/1980 installing solar panels! It was called Solar World, strangely enough.......but now I am out of touch!


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## webbie (Nov 22, 2011)

Oh, that tool link from Garys site is cool - this is a pretty accurate idea of the sunrise and sunset - and the dang trees!


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## GaryGary (Nov 23, 2011)

Hi,
This is a site survey tool I like (probably because I wrote it  -- its fairly simple to go through and use, and most people end up with a better understanding of the path of the sun in relation to the house.

It will tell you for any hour of the year whether your proposed location is in shade or not.

http://www.builditsolar.com/SiteSurvey/site_survey.htm



Gary


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## velvetfoot (Nov 23, 2011)

Would charging an electric car enter into the storage aspect?


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## SolarAndWood (Nov 23, 2011)

mbcijim said:
			
		

> The ITC as a cash grant expires 12/31/11.  ITC is the federal 30% tax credit.  It will be reverting back to a true tax credit and not a cash grant.



So, the only difference is you need to be able to take advantage of the tax credit going forward?


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## mbcijim (Nov 23, 2011)

We'll need input from someone with better knowledge on that one.  

Some "tax credits" allow you to actually get a check back from the government.  Some Tax Credits can't put you into the positive.  You can usually carry it forward but hopefully someone here knows the exact answer.  

I'm always owe, so I don't know!  

Someone hear knows.  Bueller?


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## Slow1 (Nov 25, 2011)

In MA you have the Mass CEC helping out as well.  For residential you can get rebates (at least as of this year) along the following lines:

NOTE: The amounts/watt I'm posting are approx and based on my memory - use this as a guideline only to relative levels, I expect I'm within 10c either way on these.

Base rebate approx  0.85/watt (up to $4K)
MA component rebate 0.??/watt (not too large)
"Moderate Income OR Moderate home value adder" 0.75/watt

This quarter only (first time ever) - Tornado affected rebate adder 1.00/watt (not sure of max)

All these come right off the top.  Then MA tax rebate of $1K comes into play and the Federal rebate.

After all this, the SREC scheme comes in for the next 10 years with the regulatory mandated floor on value ($300/SREC) which have been trading at around $500/SREC, so figure those in at $285/SREC for conservative calc for the first 10 years of your payback period.

Other thing that many may not be aware of is that there is a program available to get some financing for 0% applied (up to 15K) toward the project over an 8 year term.  

Best way to get the numbers that apply to your situation is to get an honest installer who sells systems (not a lease agent) and see how they spell out for your home/situation.  You should NOT have to pay anything for the analysis of your site and you should be able to get multiple bids at no charge just like any other project of this scale.  

MA is pushing solar hard so there are good incentives to adopt it.

Now on a related topic - buy/own vs lease.  There are tons of companies popping up to lease solar systems and the marketing message is getting pretty compelling.  However, every time I roll the numbers it comes out the same to me that ownership is still the best option.  Seems very much like the mortgage deal in many ways - there is money to be made here in getting the rights to good roofs/locations and those with money to invest are going for it.  The artificial floor on the SREC market price has done this - homeowners should take note and learn the implications to payback and beyond.


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## GaryGary (Nov 25, 2011)

Hi,
This is what the Dsire site says about the federal credit:
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US37F&re=1&ee=1

Excerpts: Expires 2016, "Excess credit generally may be carried forward to next tax year" 

The http://www.dsireusa.org/ site has info all of the state rebate/credit programs as well.



The EnergyStar site on credits: http://www.energystar.gov/index.cfm?c=tax_credits.tx_index
"Requirements
Photovoltaic systems must provide electricity for the residence, and must meet applicable fire and electrical code requirement."



I had thought that off-grid systems did not qualify for the credit, but I don't see anything at the sites above that say that.  Anyone know for sure?

Gary


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## mbcijim (Nov 25, 2011)

Just a caution that state grants are taxed by the federal government.


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## billjustbill (Nov 26, 2011)

mbcijim said:
			
		

> The ITC as a cash grant expires 12/31/11.  ITC is the federal 30% tax credit.  It will be reverting back to a true tax credit and not a cash grant.  This will make it harder for residential systems to get built.  If you pay $10,000 in taxes come April, it won't be an issue for you.  But if you're used to cash back then this may pose a problem as I am not sure the ITC can be used that way.
> 
> You can extend the cash grant until 9/1/12 (check with a professional) by spending 5% of the cost before 12/31/11.



Could you explain what is expiring on 12/31/11 and what ITC means?  

I'm on the borderline of getting a 3.5kw PV system installed by December 31st.  I found this link and their dates are different:

http://www.energystar.gov/index.cfm?c=tax_credits.tx_index


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## Former Farmer (Nov 26, 2011)

ITC = Income Tax Credit?????


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## macmaine (Nov 27, 2011)

velvetfoot said:
			
		

> Would charging an electric car enter into the storage aspect?





Yes but not yet from what I understand

There is an ability to do v2g charging
Where you could "dump" extra wind or solar
Into EV then draw it back as needed
Part of the whole smart grid smart meter
This is close but not ready for prime time
A very cool way to make it easier to drive 
Renewable electrons at the same time making the grid better
Able to handle renewables and to decreae the need for 
Dirty gas and coal as"base load"


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## DaveH9 (Nov 28, 2011)

The income tax credit for residential PV is good until 2016. The ITC for commercial is also good until then. What is expiring Jan 1,2012 is the option for COMMERCIAL pv installations to take the a grant instead of the tax credit. Residential never had the option of a substituting a grant for the tax credit.

Let's hope that the ITC stays active and is not repealed.


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## mbcijim (Dec 2, 2011)

Thanks DaveH9, haven't been on here for a few days.  You know the rules better than I apparently.  ITC, yes, is investment tax credit.


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