On Fri, 19 Aug 2011 00:06:47 -0500, G. Morgan wrote:

You can bring your electricity down to zero; but you can't go lower.
Can you accumulate credit with the power company for later use?

The way PG&E works it out here, is that they don't charge you for
electricity for the whole year. (Well, to be precise, they charge a nominal
amount, I think it's less than $10/month, just to be in the program ... but
that's a detail.)

All year, they keep track of what you use (we all have smart meters so they
know what you're using instantaneously).

Then, on December 31st, they tally it all up:
- If you didn't generate as much as you used, you owe them some money
- If you brought it down to exactly zero, nobody owes anyone
- If you brought it below zero, they say thank you for the free electricity