If a system generates an excess of power during the afternoon and the homeowners run the AC at night, the electricity used to cool the house isn’t added to the meter. The electricity meter actually runs backwards to credit homeowners for the energy they added to the grid! Once you run out of your energy credits, your meter goes back to running forwards, and on the next sunny day, it will run backwards again. Net metering allows the excess electricity produced by your system to cover the times it doesn’t produce enough.