Most Southern California homeowners — whether they're served by Southern California Edison (SCE), LADWP, or PG&E up in Kern County — are now on a time-of-use (TOU) rate, often having been moved onto one automatically. Understanding how TOU works is the difference between a solar system that saves you a little and one that saves you a lot.
What time-of-use actually means
On a TOU plan, a kilowatt-hour doesn't cost the same all day. Power is cheapest in the middle of the day and overnight, and most expensive during the late-afternoon and evening "peak" — on SCE's most common residential plans, that's the 4 p.m. to 9 p.m. window when everyone gets home, runs the AC, and cooks dinner. Those peak hours can cost dramatically more than off-peak power, and the gap is widest in summer. In the high desert — Lancaster, Palmdale, and the rest of the Antelope Valley — where triple-digit afternoons keep the AC running straight through that 4–9 p.m. peak, the difference adds up fast.
Why solar alone leaves money on the table
Solar panels do their best work at noon and taper off as the sun drops. By the time peak pricing hits at 4 p.m., production is fading — and by 6 or 7 p.m. it's effectively done. Without storage, you end up buying expensive grid power during the priciest hours of the day, even with panels on the roof.
How a battery beats the peak
A home battery charges from your panels during the cheap, sunny part of the day and then discharges during the expensive evening peak. Instead of buying 4–9 p.m. power at top rates, you run your home on stored solar you banked for free. Done right, this "peak shaving" is often the largest single line item of savings on a modern SoCal solar bill.
Small habit changes help too
Even before storage, you can shift flexible loads off the peak window: run the dishwasher and laundry mid-day or late at night, pre-cool the house before 4 p.m., and schedule pool pumps and EV charging for off-peak or solar hours. These tweaks won't replace a battery, but they stack with one.
It ties back to NEM 3.0
Time-of-use pricing is exactly why California's Net Billing Tariff (NEM 3.0) rewards self-consumption. When peak grid power is expensive and export credits are modest, the smartest move is to use your own stored energy when it's worth the most. TOU rates and storage are two halves of the same strategy.
The takeaway
If you're on a time-of-use plan — and in SoCal you very likely are — the goal isn't just to make solar power, it's to use it at the right time. A system designed around your SCE, LADWP, or PG&E peak window, not just your roof size, is what turns a good electric bill into a great one. ACS has designed solar and battery systems across Southern California — the Antelope Valley, Los Angeles, and Ventura counties — since 1983, so request a free estimate to see what makes sense for your home and rate plan.