I have solar that's oversized for my house and usage. My house is national gas, but the previous owner put on an addition but made that an electric zone. I had that room properly insulated and shut down the electric zone. It saved me a small fortune, and now I have a large negative balance with National Grid. I've used my negative balance to credit friends and family for 80 cents on the dollar.

I live in Worcester county and purchased solar panels about 5 years ago. I cannot attest to the current benefits, but when I bought my panels I got to write off 1/3 of the cost on my federal taxes and an additional $1000 on my MA state tax. I also get paid ~$2k a year (tax free) in renewable energy credits for 10 total years. These factors made it worth it to me, and I haven't had an electricity bill in years -- only a low interest loan payment. In fact, I actually have accrued a large credit with National Grid as my solar system generates much more than I need. I am allowed to credit to then my parents' or friend's account with my excess credit. I will offer them 80 cents on the dollar and it's a good deal for both side. Anyways...

My understanding is that if you elect not to buy your own panels, and someone offers to put them onto your roof for "free", they get all these incentives. Furthermore, my understanding is that the benefit they can therefore offer you a static electricity bill for a number of years which may be a good deal as we all know utility bills rise.