Net peak is the hour of highest electricity demand after subtracting solar and wind output, which on a solar-heavy grid falls in the early evening rather than mid-afternoon. It is the hour that grid planners, and increasingly grid batteries, are built around.
On the California grid
- CAISO batteries discharge in hours 17 through 22, the net peak window, after charging in hours 10 through 13 when solar is abundant.
- Gross demand passed 50,000 megawatts on September 9, 2026, but the tight hour was after sunset, when solar had dropped out and batteries carried the difference.
Why it matters for parking
The net peak is when commuters arrive home and plug in. EV charging that can be shifted out of that window is worth more to the grid than charging that cannot, which is the argument for charging at the workplace instead of at home.