A weird new energy market?

CleanTechnica - Community Solar Now Available Nationwide From Arcadia Power:

And it will be people who tend to have lower average electricity bills ... who are actually the ones who will be able to shave the most off their electric bill.

That is because the credit deducted from your normal bill from your utility is a hard dollar amount, based on how many panels you buy, which generate power and get paid a high rate in Massachusetts or Washington. You earn the credits from this solar investment in dollars. Those dollars simply get deducted from your bill.

I don't quite get how this works – what, exactly, is being traded for what; and what is actually being delivered. It has some of the "let's pretend" characteristics of a futures contract.