Netmetering?

Net metering is a billing arrangement that allows solar system owners to receive credits for the excess electricity they generate and send back to the grid. When your solar panels produce more electricity than you need, the surplus is automatically fed back into the grid. The utility company then credits you for the excess energy, which can offset or reduce your future electricity bills.

Credited to customer's next bill at retail rate, except for certain community-owned facilities. After 12-month cycle, customer may opt to roll over credit indefinitely or to receive payment for credit at the energy supply rate.