When the Grid Asks You to Cut Back at 4 p.m., Homes With Batteries Don't Have to Sweat It

When the Grid Asks You to Cut Back at 4 p.m.,
Homes With Batteries Don't Have to Sweat It
Californians who lived through the September 2022 heat wave remember the alerts. On September 9, 2022, the California Independent System Operator extended a statewide Flex Alert from 4 p.m. to 9 p.m. as a prolonged heat wave pushed electricity demand higher and tightened available power supplies. The grid operator also issued an Energy Emergency Alert, signaling that supply shortfalls were anticipated.

What the grid asked households to do
CAISO's guidance was clear. Before 4 p.m., residents were asked to pre-cool their homes to 72 degrees, run major appliances like washers, dryers, dishwashers, and ovens, and close blinds and drapes. During the 4 to 9 p.m. window, they were asked to set thermostats to 78 degrees or higher if health permits, avoid using major appliances, and turn off unnecessary lights. Those hours were chosen for a reason. Late afternoon and evening is when air conditioning demand peaks and solar generation declines, creating the most stress on the grid.

The grid has improved, but the peak has not gone away
Since 2022, California has added massive amounts of battery storage, and the CPUC reports the state has not needed a Flex Alert in three consecutive summers. That is real progress. But the evening peak still exists. It is still the most expensive time to use electricity on SCE, SDG&E, and PG&E time-of-use plans, and extreme heat, wildfires, or equipment failures can still push the grid to its limits. When that happens, most households face the same trade-off as in 2022: sacrifice comfort on the hottest evenings, or pay peak prices to keep cool.

Battery homes play by different rules
A home with rooftop solar and battery storage handles grid stress very differently. During the day, solar panels produce power and charge the battery. When the 4 p.m. peak arrives, the home runs on stored energy instead of drawing heavily from the grid. The air conditioning stays on, dinner gets cooked, and the family stays comfortable, all while reducing strain on the grid. That is the same strategy the state now uses at grid scale, with batteries storing midday solar and releasing it in the evening. A home battery simply brings that strategy to your own house. And if an emergency does lead to outages, the battery keeps essential loads running. Many battery owners can also enroll in programs that support the grid during peak events, turning their homes into part of the solution, subject to program eligibility.

Comfort without the purchase
Through third-party ownership programs, qualifying homeowners can get solar and battery storage installed without buying or financing equipment, while enjoying lower energy costs and backup power. The next time the grid is stressed on a hot evening, you can either turn up the thermostat and wait it out, or let your own stored solar carry the load. If you would rather be in the second group, see if your home qualifies.

To find out if your home qualifies for a TPO solar and battery program, visit myhomesolution.org/california_public_utility_commissions