Monday, July 29, 2013

Solar, part 3

A company called SolarFlair is doing the Solarize program for Newton and Brookline, and offering much better base pricing and a 10-year labor warranty rather than SunBug’s 5-year labor warranty. The base pricing goes down to $3.69/watt with SunBug if enough people sign up, while SolarFlair starts at $3.69 and goes down to $3.14. Of course, I don’t live in Newton or Brookline. I wonder how SunBug got the Solarize Medford contract. Perhaps the adders for better panels and other upgrades cost a lot more with SolarFlair.

Aside from the massive uncertainty built into the SREC program (a 5kW system might be worth anywhere from $8000 to $25,000 in SRECs over the next 10 years, or possibly even less than $8000), it turns out we cannot get an enforceable long-term agreement with the city to be able to trim the city-owned shade tree if it grows too tall. Any future city government would be able to unilaterally revoke any such agreement or permit.

And we’d need to add snow guards lower down on the roof to deal with the tendency of solar panels to release their snow cover in one big whoosh, since that avalanche of snow from our roof configuration would be coming straight down at our front steps and our poor abused garden.

The final numbers as I understand them: We could spend about $24,000 up front for a 4.9 kW system, get $3900 back in a state rebate, $1000 back in a state tax credit, and $6000 back in a federal tax credit. That’s a net cost of $13,100. We’d generate about $600/year to $800/year in electricity at today’s 14 cents per kWh. We’d also earn $1000 in SRECs per year, or maybe $1500, or maybe $600, or possibly less or more. Conservative numbers would be $1200 per year payback, and that assumes we don’t have shade problems. If electricity prices go up a lot and the state fixes the SREC price support to be a true floor, the payback could be much better. But the conservative numbers don’t justify the costs right now.

The way to make the economics work are to put up more and cheaper panels, and treat the credit on the roof work as a deduction from the solar. So we spend $20,000 up front, get $4000 back in a state rebate, $1000 back in a state tax credit, and $8000 back in a federal tax credit. That’s a net cost of $7000. At $1200 per year payback, that looks worth it. Barely. And that’s not worth the continuing headache.

Next year solar costs will be different, the SREC program will be different, and some of what I’ve learned will no longer apply. And so it goes, round and round the sun.

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