The homeowner’s guide to solar power

January 10, 2014, 8:17 PM UTC
The author’s home, in Massachusetts.

FORTUNE — American homeowners added more solar power generating capacity during the third quarter of 2013 than ever before, according to the Solar Energy Industries Association: 186 megawatts, up nearly 50% year over year. A tiny part of that — 0.002% — was recently installed on the gently sloping, south-facing roof over my kitchen in suburban Boston.

Mine is a 15-panel, 3.75 kilowatt system, designed to replace about 80% of what my family would normally draw from the grid. If it produces as promised for at least 25 years, we’ll cut our household carbon footprint by 62 tons and save $25,000 in utility bills. Total upfront cost: $12,951. Payback period, thanks to a ridiculously attractive package of state and federal incentives: less than five years. I know, why would anyone not?

I love my new power plant. Because I can, I monitor it compulsively, on my laptop and on my phone. At this moment, for instance — 11:45 AM on a bright, bitter-cold January day — my roof is generating 2.51 kilowatts of electricity. Since the dog is the only one at home, I’m pretty sure my meter is running backwards. That warms me.

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That said, I’ve learned a few things over the past several months that I probably should have known going in. Nothing that would have changed my mind, but still. Herewith, my surprises:

The hassles

The incentives are generous, to be sure, but harvesting them all takes vigilance, effort, and time. This year I’m anticipating a 30% tax credit from the feds worth about $3,800, plus another $1,000 from the Commonwealth of Massachusetts. Alas, I won’t see that money until tax time, which in my case, as a habitual extension-filer, may not be until late summer.

Those are one-time offers. Most of the payback will come in slow drips over several years from the sale of Solar Renewable Energy Certificates, known as SRECs (pronounced S-RECs). Electricity producers buy them from solar producers like me to meet their solar generation requirements. Once a quarter, I have a 10-day window in which to take an eyeball reading of the meter in my basement and report the number of kilowatt hours I’ve produced to my SREC broker. (I could have paid extra for automatic reporting; that might have been a good idea.) The price I get for the SRECs is determined by the market, which in Massachusetts happens to be a bit soft just now, thanks to the flood of new installations. Happily, the state runs an SREC clearinghouse that guarantees me a minimum price for the next 10 years. That sale occurs once a year, also in summer. Bottom line: I stand to generate a total of about $10,000 over the next decade, but it will take until 2024 to collect the full amount.

The grid

When Hurricane Sandy blew through Boston in the fall of 2012, and many of my neighbors lost power for days, I had a happy vision of my own solar future. As long as the sun rose on the morning after, I figured, I’d be up and running.

Not so. My setup, like virtually all home systems, is designed to shut off automatically when the grid goes down. That made no sense to me at first, but I get it now. Power flows both ways. If all the solar houses in town were feeding an otherwise disabled grid, there would be no way for workers to safely repair downed transmission lines.

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It’s not impossible to fix, just complicated and expensive. You’d need a surefire way to store power (batteries, lots of them) or make power (a generator) whenever you’re not making any with solar, which where I live is most of the time. In the dead of winter, even on sunny days my system wakes up around 8:00 A.M. and goes to bed around 4:00 P.M. David Crane, CEO of NRG Energy (NRG), tells me that eventually his company will offer an affordable solar/natural gas generator combo package suitable for the residential market, providing true independence. But not yet.

The vagaries of weather

Boston has an average of 2,634 sunny hours per year, according to the National Climactic Data Center. Not in the same league with Phoenix (3,872) or Las Vegas (3,825), certainly, but not as bad as you might think. Columbus, Ohio has only 2,183; Houston, 2,578. But what Boston gets a lot of that Houston doesn’t is snow, and when we get a storm like the one that arrived the week before Christmas — heavy snow topped with an icy frosting that sticks to the roof for days — my system stops producing.

Living where I do, I expect to shovel the driveway and the walk; I never imagined I’d be thinking about shoveling the roof.