One interesting thing about PVs right now is that it is getting VERY close to it being cheaper to get one’s electricity from PVs rather than one’s local electric company.
1. Electricity in MA (especially if you are doing GreenUp, GreenStart, the Wind Fund, etc to be 100% renewable sourced) is basically 20 cents per KWh. Or more. In other words, expensive.
2. Electricity in MA (and New England generally…) is fairly dirty unless doing GreenUp. The mix (last I checked in Feb 2010) is roughly 1/3 coal, 1/3 natural gas, 20% coal and oil, 10% renewables, 10% “other”). Anyway, the basic point is it’s not very green yet.
3. The grid-parity calculation I did in excel is even without factoring in state and federal subsidies and things like S-RECs (where the state pays you $0.38/KWh produced for the “greenness”…)
4. There is pretty decent sun in MA. The quick calc that seems to get used is that if your panels are basically facing south, you take 1200 * system size, and that’s the number of KWh produced in a year (So a 6KW system makes 7200 KWh (an ave of 600 Kwh/month).
5. We don’t happen to have net-metering here in Stow, because our electricity is thru a “municipal”… Hudson Light and Power… and they don’t do net metering yet. Soon I hope! What this means is our payoff calculations get a little trickier since we will have to pay pull price for electricity we use when it’s dark or cloudy.
6. Since we are adding PVs directly to a house we are buying/building, it gets rolled instantly into the 30 year mortgage, so… the basic cashflow calculation is that we are paying a little more for our mortgage with PVs, but our reduction in electricity bills offset this increase. So we are cashflow positive from day one.
7. A more complicated analysis would factor in opportunity cost (what the $ could be earning in investments) and tax-deductions for mortgage payments. But also the subsidies.
8. Protected from grid-electricity price increases!
In the end, I don’t even care so much about $ payback periods. I would MUCH rather use the sun than fossil fuels. So it’s worth it even if my calcs are off slightly and it’s not quite a money maker.
But we really are there. So if you’ve got some sun, it’s time, or just about time to go solar in MA.
FWIW… I would advise someone ready to “wade in” to just ask to use PV microinverters… you can easily gradually increase the number of panels without problem. And partial shade is not a problem with microinverters.
So start small and add more later!
And insulate your house a little more first! That will probably save you even more money! At least in MA! “Energy audits” from your electricity or natural gas company are usually free. And insulation improvements are subsidized as well.