Do Batteries Finally Pencil Out? The NEM 3.0 Battery Math

For years, home batteries were a lifestyle purchase. They kept the lights on during outages, but the economics were soft — under old net metering, the grid already acted like a free battery.

NEM 3.0 changed that. When exported power earns ~$0.06 and evening power costs ~$0.50, the gap between those two numbers is what a battery captures. Store your own midday production instead of exporting it, discharge it through the 4–9 PM window instead of buying, and the battery earns that spread every single day.

The daily cycle

A typical day with storage looks like this: the array covers the home and fills the battery through late morning and midday; from late afternoon the battery carries the evening peak; the grid only steps in late at night, at off-peak rates. Modeled over a year on SCE rates, storage typically shortens system payback rather than lengthening it — a reversal from the old rules.

Backup is now the bonus

Outage protection didn't go away — whole-home transfer keeps essential circuits live when the neighborhood goes dark, and the system re-forms its own grid automatically. It's just no longer the only justification. Under current rates, the battery works for a living even in years when the grid never blinks.