In North Carolina, Tesla manages the Virtual Power Plant technology for the power company, but details on the bill credits you receive and how all that works is done by the power company. I'm pretty sure that's the model used in all states. Here's a link to the Duke Energy web pages for the program in North Carolina.
Duke Energy - EnergyWise Home
The summary of the Duke Power program is the amount of "Credit" you get has nothing to do with the amount of energy (KWHs) you send to the grid. The "Credit" is purely based on max KW rate of power you have the ability to support the grid. And that makes sense, because this is helpful to the power company when they need deal with high short-term load peaks. So the max rate of power you can send to the grid is what's important to them. Also, once you sign up, you have to stay enrolled for the whole year, and you get the option to opt out of fixed number of demanded events per year.
IMO the NC program is an unbelievable opportunity for people with battery storage system. Because unlike net metering, these credits are actual monetary credits. Meaning they pay for anything on your power bill include fixed fees and taxes. And if you get enough credits, they will send you checks for the money they owe you.
I'm in the process of getting 2 PowerWall 3s installed in both my houses just for this program. This will be in addition to the existing solar and battery storage systems I have in both houses. After the installs are done, the power company will essentially pay me $2500 a year for being in these programs. And there is a minimum 10-year contract I'll have with them, but no reason to expect the program won't go longer than that.
A good friend of mine, that I help with his solar system, is already in the program and getting paid.
