Seriously Thinking All Solar in MA

If the tech is there, when I pay off the house in a few years I'd really like to go solar for all my electricity. Has anyone done this, especially in MA?

If this is do-able in five years and the tech has advanced, I'd like to buy an electric vehicle and stick it to the oil companies.

I'm still in the beginning stages of research and maybe you can all help me if I have missed something. I'm thinking replace the roof, then put panels on it for my elec needs. I have a 1600 sq ft dutch gambrel with a very large south-facing roof surface area on a half acre.

Main source of heat is the wood stove. In the last 3 years, I seem to peak at 650-700 kWh for July.

1) What's the tech like (and cost) for battery storage to power my house at night? I know that some people move their unused power back to the grid. Is it one or the other or can you fill the batteries then sell the extra power (say during the summer when the sun is most intense) back to the grid?

2) Is there some sort of defroster/heater that takes care of snow accumulation after a storm or do people use a roof rake or none of the above?

3) Anyone taken advantages of either federal or MA state tax credits or some other kind of incentive that exists?

4) I'd like to use my current provider, National Grid, as my power back up if something does break due to storm damage or something unforeseen. Is this possible?

5) How are the warranties for the solar equipment and installation? I can do some basic home repair and upgrading, but I would definitely contract this job out.

6) Anyone totally solar and have you worked out when your realistic break even point is/was?

Thanks.

A few folks around here have gone solar PV, like begreen.

A good solar forum to digest might be: http://www.wind-sun.com/ForumVB/forum.php

In round numbers, figure your annual elec output is your panel capacity * 1000 hours. To get 7000 kWh/r, you would need a largeish 7000 kW array grid-tied. To go off grid, you lose some energy cycling into and out of the battery, and you'd want a 9-10 kW array. With the batteries (which are very heavy lead-acid like the ones in golf-carts), the off-grid system will cost 2x as much as the grid-tied, and it is hard to switch back and forth. Better/cheaper to grid-tie and buy a genny for backup (if you care).

If you are serious about going 'all solar' it will pay to replace all your appliances with maximum eff models and drive your annual usage down.

I am sure the experts will be along shortly.

MA has a pretty good SREC (Solar Renewable Energy Credit) program. Basically, you get paid for every MWh that you produce. This can make a solar system pay off pretty quickly (5 to 7 years) after Federal tax incentives. You will likely get some type of net metering as well. Cost of storing on-site with batteries is pretty high - it is much better to go the grid-connected route and buy a few small(er) backup batteries and an inverter that can be grid-tied AND battery-based to get you through a short outage and keep the important things powered.

I'm in MA - and I put my array up last fall.... I don't drive an electric vehicle (yet) I don't think that tech is quite mature cost wise yet to jump on.

I think your idea of replacing the roof first is good - I certainly would make sure that the roof face that will be under the panels is in good enough shape to outlast the panel installation as the cost to pull down and re-install the panels is likely to rival the cost of that one face being roofed.

It sounds like your peak power use is similar to where ours was last year, our average is less than 500Kwh/mo (lower now than when we put the array up, that's another story).

Now to try and answer your questions:
1) Battery storage - not a good idea. Your research should quickly confirm this: cost/Kwh over the life of a battery system will be much higher than just buying your system, in summary the reason for this is that you need far more panels than you would otherwise, also the maintenance and general replacement cost of the batteries is very high for what they are getting you.

2) Not that I'm aware of. IF your roof is sloped well then the ice/snow will slide off panels much faster than your normal roof. We didn't have much snow this year to really test this, but the few times we did I was surprised at how quickly it did slide off. I still may consider a soft roof rake in the future, but for now I doubt we'll need it.

3) Absolutely! Without the incentives/credits etc it isn't going to make financial sense for my budget. With the credits and SRECs in MA my anticipated cash break-even point is within 6-7 years, and it could be as short as 4.5 years if the SREC market remains as high as it is now.

4) Just stay grid-tied (no batteries) and you are all set. Forget the batteries - spend your money on a backup generator in case of grid failure and you will save a ton of money and actually have less impact on the environment (all those batteries being manufactured) as well.

5) Warranties are good, obviously depends on the companies doing the work (and their ability to stay in business for the duration). I have a 10 year installer warranty on my system soup to nuts. Panels are 25 years (with some interesting terms that make it almost worthless as it gets close to the end.. read carefully, but it is industry standard). I fully expect to replace inverters (mine are central) in 12 years or so, but that is budgeted for.

6) My system should pay for itself in within 7 years, possibly 5 if SREC market is strong enough. So far it has been collecting about 200Kwh/mo more than we use so I have been building up a credit on my electric bill each month. Not bad for the winter months in my opinion. So does that qualify as "totally solar" to you? Have to get through the whole year to really know and several more after that to have averages I'm sure, but I'm feeling very happy about it so far.

I'm not sure if waiting to build it out is a good idea or not - solar systems are going down in price I'm sure, but incentives may not always be there. It is of course an individual decision, but I'd look to see what it would take to build your system now and then evaluate your options. You may be surprised at what you can do, a low interest loan may be worth doing as the environment in MA is very positive for this sort of investment if your home is situated well for it.

I have a friend with an array of PVs on a barn with a standing seam roof. He has at two rows high and a partial third row. The roof is 12 12 pitch (45 degrees), When we have a "wet" snow storm he has to rake them otherwise he has the remote chance that the surface of the snow will freeze and he is out of commision for several days. If its fluffy snow, it normally sloughs off once he starts raking.

I reset my panel angles manually so in the winter they are at 30 degrees off vertical (latitude 45 minus 15 degrees). Even at that angle I do have storms, generally wet, that wil cover the panels. They usually melt off in a day or so, but a quick rake (they are pole mount so not very high) in in a few minutes whatever snow is remaining melts off and I am cranking out over the design output due to cold temps and snow reflectance.

I will be upgrading the array with larger black frame modules this year and am curious if it make much of a diffference.

Some MA company advertises on the radio that they will set your house up with solar and then you only pay them for the electric that you use and according to the commercial the rate they charge will be cheaper than the grid. I don't remember who but they have to be advertising somewhere else also. It sounded like they owned the panels and batteries and you were just paying like you pay the electric co.

Thanks all. Very good info so far. Obviously all of this breeds more questions.

A) Based on input here and my own research, batteries do not seem to be the way to go. That is unfortunate, but I'm okay with that. Batteries appear to make solar into a giant hobby that requires lots of attention. I already get 90% of my energy from a wood stove. I love burning with wood, but I don't need another hobby like that.

B) Extra power is a credit, not a dividend? Interesting. What is your array rated for in watts? When rated, is it maximum full sun optimal angle? What would be the wattage for your system on a completely overcast day? 30% of the max?

C) What designs/companies seem to be the most efficient? I haven't measured my roof, but simple #s - let's say I have 1,000 sq ft of space that I panel. How many kW can I get from that?

D) Let's say I need 500 watts at a given moment, but am only generating 200 because it is cloudy. What happens? Does the electric co give me the other 300 for that moment?

E) Over 95% of my lights are CFL or are standard florescentMost of my appliances are energy star. Can you run an electric oven? What does it take to charge a car currently?

F) Anyone have photosensors and motors on the array that help it track the sun to maximize efficiency?

G) Is the MA tax incentive currently just when you purchase the system or do you get some or all of it year to year? What about fed credit?

Someone else needs to answer that who is familiar with Mass. Do note, the subsidy systems are political beasts that can and will change. The current systems are effectively surcharging the people who dont use solar to pay others to install solar, this works intitially but as Germany and Spain learned, eventually the other ratepayers are unwilling to pay that surcharge, so the incentives are cut, sometimes retroactively. IMHO You are far better getting the money up front than depending upon long term solar incentives. Also make sure that your state has a solar pproperty tax exemption or the town could increase your taxes each month more than you generate.

A) Good call there.

B) Getting set up as a "Co-Gen" or "net metering" in MA, you basically will turn your house meter forward and back depending on your 'net' usage at any given moment until the end of the billing cycle. Then if your meter has moved in a positive direction, you have a +usage and will buy that electricity, if it is down for the month, you will get a credit for that power. No "dividend" involved. Each month I have a $4 "customer charge" just for being hooked up, then my usage of power (+ or -) * approx $0.13 (there are a bunch of categories that add up to this) is added to that, then it nets out to the amount owed or credited for the month. So, if I were to have used 100Kwh, then my bill for the month would be $13 + $4 = $17. If I had generated 100Kwh more net for the month (i.e. my meter was down 100Kwh from previous read) then my bill would be $4-$13= <$9> credit. IF I have a credit it just carries forward to next month - they won't cut a check. Right now I have a pretty decent credit built up, will see if it survives the summer A/C season or not.

Arrays are rated in watts DC - there are sites that can help you convert this into your AC watts (PVWatts) that you can expect to get given your location and angle of roof etc. Easiest way to get this may be to get a company to do the analysis for you and they will give you a good write-up if they are worth anything. BTW, you should NOT have to pay a penny for this evaluation, if they want a deposit or anything, call someone else.

My daily production does vary depending on sun etc. My best day produced around 38Kwh, my worst was 2Kwh so far. Right now on a fully sunny day I expect about 35Kwh/day but in the winter it was more like 20Kwh (shorter days and lower sun angle gave more shading - every site is different). Our average use is around 14Kwh/day and so far this month we're generating about 25Kwh/day average so we have a comfortable surplus which of course makes the desire for an electric car grow... but that's another discussion...

C) Details on best panel etc - go read one of the solar forums... you can drive yourself cookoo on this just like picking the 'best' wood stove. As to how much can you get from your roof, again - get a company out to do an estimate and find out. There are competing factors not all panels are rated for the same power/panel but costs are related there too - finding balance is the key.

D) In a grid-tied system your usage doesn't care a bit about your panels. If you draw 1Kw for various uses you get it - from the grid or panels, your appliances don't know or care. If it happens that your panels are producing more than the 1Kw then your meter will 'spinning backwards' but if your panels are producing less, then the meter will be going forward and the numbers will be increasing.

E) See answer to D above - you can run whatever normal appliances/devices you have - panels and devices don't care.
What does it take to charge a car? that will depend on the electric car. If you are talking about current draw I believe home charging systems are somewhere around 3.3Kw. In terms of daily Kwh use, batteries come in different capacities - the Nissan Leaf is 24Kwh so assuming you were to drain it to 20% daily and recharge it fully then you could perhaps budget about 19Kwh/day for this.

F) Tracking was answered above I believe. Not a good option for roof mount really as you would have to consider wind issues as well...

G) Tax incentives are all pretty immediate - you benefit on your next filing anyway (i.e. this tax year so you get it when you file next spring, not today). However, the SRECs don't start for about 9 months after you are up and running and then they pay out over the next decade so that is very much spread out. SRECs are worth more than the tax incentives in the end.

A couple other thoughts btw - Someone mentioned the leasing companies. That is an option, have someone put an array on your home and then buy the power from them for a reduced price or other scheme. I don't believe these really makes sense as you are giving the vast majority of the benefit to the leasing company (read they get the SRECs) and you are taking on the responsibility/risk if you sell the house to convince the buyer to take over the lease etc, but perhaps it may make sense for someone out there. I've built some financial models to compare these options and I just can't see doing the lease other than the obvious "I don't have the ability to come up with the investment capital to buy." If that is the situation then my opinion is to simply not do solar.

I live in upstate NY where consecutive sunny days aren't the norm, and we power our house here with our solar array and battery back up alone. Its all about recognizing that the available electricity isn't infinite, making your house as efficient as possible and eliminating "ghost loads". Without the willingness to do this you'd spend a fortune on a big enough off-grid system to suit your needs, or just keep paying a hefty electric bill if grid-tied.

I've always though that the best arguments for grid tied vs off grid systems are based on your proximity to the grid. It makes little sense to invest in a battery bank if you're already hooked to the grid or close enough for a reasonable investment to hook up, while if you're a sizable distance away you may spend many thousands getting the line to your house, possibly justifying a battery bank.

If you're in a snowy and cold winter region and your panels are on the roof you'll possibly have many days of no gain at all while the snow sits on your panels. And cleaning them off presents problems too. Aside from more snow to clean (that's well above your easy reach) there'll be some days of snowfall that freezes to the panels that you won't be able sweep off, and if it stays cold it could be blocking your electric production for days - the economic viability of the system is it's efficiency, so losing days of production is a loss. If you have room on your property to alternately mount your array it's well worth it since you can get an adjustable array that not only offers you the ability to maximize your input by adjusting the angle to the sun's seasonal track, but also gives you the ability to modify the angle during the winter so the snow won't stick to the panels.

Good point. Those of us who are already hooked up and only have to pay a nominal ($4/mo in my case) fee to remain hooked up really do have a hard time making a financial argument to install a battery bank. Not to mention that some financial incentives (SRECs etc) are only available if you are grid-tied. Now, if I were building in a location not currently serviced with power and was staring down several thousand dollars just to get hooked up (and the prospect of being last on the priority list to be restored in a storm...) it would perhaps be a different calculation.

1) Peakbagger: "You pay more for efficiency if you are the government you can buy panels that are twice as efficient as what is currently available. "


Is this really true, why is that?

2) Slow1: I'm not interested in leasing. I would either buy the system or not get it at all. Grid tied makes the most sense for me.

3) Seems like getting the electrician to wire for a back up generator while they are configuring my house wiring for solar would make sense. I do not currently have a generator. I've been in this house for 9 years and have lost power for more than a day two separate times, both during snow. Thus, the plan would be solar during the day and a small generator at night/before snow melt off panels in case of a grid power outage. Anyone done this?

4) To help estimate my load I've looked at PVWatts and am doing the calculations for my major energy consumers. I'd like to go a bit bigger than I think I might need.

Volts X Amps = Watts

Watts X 1.42 to account for energy loss due to AC/DC conversion, correct?

Thus, a 5kW array only produces 3.5kW of power during optimal sun because efficiency is only ~70% converting panels to appliances, right?

5) Slow1, who did you go with for an installer or was it a DIY? Please pm me if you'd rather not say here.

3) - If you are suggesting that during a power failure you expect to draw off the solar array, then sorry but this plan won't work. Without a battery system in place and an inverter designed for this purpose you are just not going to get this to work out. Without going into the gory details, bottom line is that grid-tied systems don't work this way and although you CAN design a system to work as an emergency backup system, it basically becomes a battery backup system with solar charging it so you are back to the same economics as you were looking at using the batteries to begin with. Go back to your original statement - 9 years and only lost power for more than a day twice? Just plan on the generator for the whole 24hr period and you will spend far less money and have a cleaner solution. Apply the KISS principle - yeah, it would seem to be a bummer having all those panels sitting idle for a couple days, but such is life. 2-4 days over 9 years isn't bad.

5) I went with a company called "SolarFlair" (not sure if it is two words now that I think about it). They did a good job and the quote was competitive at the time with a nice warranty and references seemed solid as well as the fact they have been around for a few years (didn't just pop into business just when the SREC market came into being). They were rather local to me so that was a nice thing for me as well.

Feel free to PM me if you wish to get into more specific details on my system or the installer. If you want to see it you can - I have a thread with pictures here somewhere.