Grid · Analysis

Thousands of home batteries, acting as one power plant

California now pays networked home and business batteries to discharge together on strained summer and fall evenings. Here is how that works in the LA basin, and how to check the real numbers.

BY THE RENEWABLE ENERGY LA EDITORS · FILED OCTOBER 29, 2026 · 6 MIN READ ·

How thousands of batteries act as one plant

A virtual power plant (a group of small batteries controlled together so they discharge on cue) is less a machine than an agreement. An aggregator, which may be your installer, your battery's manufacturer, or a third party, holds permission to send a discharge command to every enrolled battery when the grid operator or the utility calls an event. The batteries do not feed one giant wire. They each push power into their own homes or local circuits, which lowers demand everywhere at once, and the grid sees the sum.

The call usually comes on summer and early-fall evenings, roughly between 4 and 9 p.m., when rooftop solar fades but air conditioners are still running. In California that window is when the grid is tightest, and it is when the California Independent System Operator (CAISO, the nonprofit that runs the state's main power grid) issues its Flex Alerts asking for restraint. A virtual power plant answers that same strain automatically, without anyone being asked to adjust a thermostat by hand.

The programs that pay for the discharge

Two state programs do most of the paying. The Emergency Load Reduction Program, run by the California Public Utilities Commission for the big investor-owned utilities, pays enrolled customers for power delivered during declared grid emergencies. The Demand Side Grid Support program, run by the California Energy Commission, pays aggregators to stand ready and to discharge when the state is short. At last public report, programs of this kind have added up to somewhere on the order of a few hundred megawatts statewide on the hardest evenings, though the exact figure moves event to event, so check the operator's own numbers rather than any vendor's.

Separately, the Self-Generation Incentive Program, also overseen by the utilities commission, has for years discounted home storage and steered extra money toward wildfire-risk and lower-income households. That is the second life of a subsidized battery: first a rebate lowers the purchase price, then enrollment in a virtual power plant turns the same hardware into a grid resource that earns a little back each time it fires.

Which utility you're on changes the answer

Where you live decides which door you knock on, and in the LA basin that is not a small detail. If you are a Southern California Edison customer, across much of the basin outside the city core, you sit inside CAISO's grid and are eligible for the investor-owned-utility programs above. If you are a Los Angeles Department of Water and Power customer, inside the city, you are served by a municipal utility that runs its own balancing area and is not part of CAISO, so the programs and the enrollment paths are different.

People get tripped up by this split constantly, because a neighbor two miles away can be on a different system entirely. The practical move is to find your utility's name on your bill, then look up that utility's own storage and demand-response pages, then ask your installer in writing which aggregator, if any, your battery is already enrolled with. Don't assume the rebate signed you up, and don't assume it didn't.

Worth watching this month

1. Watch CAISO's Today's Outlook and any Flex Alert notices as the last warm spells of the year pass through, since those are the evenings a virtual power plant is most likely to be called.

2. Check the California Energy Commission's Demand Side Grid Support page for current enrollment and season updates, which is routine housekeeping rather than breaking news.

3. Look for the utilities commission's periodic reports on the Emergency Load Reduction Program, which post actual megawatts delivered during past events and are the honest counter to any vendor claim.

4. If you are weighing a battery, confirm whether the Self-Generation Incentive Program still has funds open in your category, since those buckets open and close through the year.

5. Ask your installer or aggregator, before signing, how many events per year they expect to call and what each pays, because that number varies widely and is easy to gloss over.

Where this dispatch reads

CAISO Today's Outlook (state grid operator), www.caiso.com/todaysoutlook/pages/default.aspx, Live grid conditions and Flex Alert notices for California's main grid, straight from the operator that calls the events.
California Energy Commission, Demand Side Grid Support (state agency), www.energy.ca.gov/programs-and-topics/programs/demand-side-grid-support-program, Program rules, participating aggregators, and payment terms for the state-run standby program.
California Public Utilities Commission, Emergency Load Reduction Program (state regulator), www.cpuc.ca.gov/industries-and-topics/electrical-energy/electric-costs/demand-response-dr/emergency-load-reduction-program, Rules and after-event reports showing megawatts actually delivered, a check against vendor claims.
California Public Utilities Commission, Self-Generation Incentive Program (state regulator), www.cpuc.ca.gov/industries-and-topics/electrical-energy/demand-side-management/self-generation-incentive-program, Rebate categories and budgets for home storage, including equity and wildfire-risk set-asides.
Los Angeles Department of Water and Power (city utility), www.ladwp.com, Storage and rebate programs for customers inside the city of LA, which sits outside CAISO.
Southern California Edison, demand response and rebates (utility), www.sce.com/residential/rebates-savings/demand-response, Enrollment paths for basin customers served by SCE and inside the CAISO grid.

Questions readers have asked

Does joining a virtual power plant drain my battery when I need it?

Most programs let you set a reserve so the battery keeps a cushion for your own backup, and events are usually short, a few hours on a handful of evenings. Read the enrollment terms for that reserve setting, because the default is not always what you would choose.

Do I get paid, and is it worth it?

You generally earn either a per-event payment or an annual amount for staying enrolled. For most homes it is a modest credit rather than a windfall, so treat it as a small return on hardware you bought mainly for backup and bill savings.

Can I take part if I'm on LADWP?

LADWP runs its own system outside CAISO, so the state investor-owned-utility programs do not apply the same way. Check LADWP's own storage and rebate pages and ask the utility directly about any aggregation option.

Will the grid operator control my house?

The command goes to the battery, not your appliances, and it only shifts stored power you already have. You can typically opt out of a given event, though repeated opt-outs may affect payments.