Solar Battery Backup and Storage in California: What It Runs, Costs and Saves

A solar battery backup system keeps the circuits you choose running when the grid goes down, and solar recharges it the next day. On NEM 3.0 it also stores cheap midday solar for the expensive evening hours. Storage adds roughly $750 to $1,000 per kWh by Lawrence Berkeley National Laboratory’s 2023 estimate, the federal credit ended with 2025, and a few narrow programs still help.

This guide covers what a battery can run, where its bill savings come from in each utility’s territory, what it costs, how California’s storage fleet is growing, and who can get help paying. For every battery guide in one place, start at home battery storage in California.

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Job one: backup power when the grid is down

A grid-tied solar system shuts off in an outage unless a battery and backup equipment let the house run as an island. With them, the battery powers the circuits you chose and solar can refill it during the day. How many appliances run at once depends on the battery’s power output. How long they run depends on its stored energy.

The three batteries most often quoted in California show the range, from each maker’s datasheet. A Tesla Powerwall 3 stores 13.5 kWh, delivers up to 11.5 kW on the grid, and lists a 185 LRA motor-start rating. An Enphase IQ Battery 5P stores 5.0 kWh and delivers up to 3.84 kVA, so homes stack several. A FranklinWH aPower 2 stores 15 kWh and delivers 10 kW continuously. Their spec sheets are compared side by side in Powerwall 3 vs Enphase 5P vs FranklinWH.

How many batteries a California home needs

Start with the loads, not the brochure. List the circuits you want during an outage, their watts, and how many hours you want to cover. At a steady 1 kW, a 13.5 kWh battery lasts about 13.5 hours before any recharge. A refrigerator, lights, internet and a few outlets fit in that. Central air conditioning, an electric range, a well pump or EV charging do not, which is why most designs back up a critical-loads panel rather than the whole house. The full method is in how many batteries a home needs.

For shutoffs that run several days, a battery that solar refills each afternoon behaves differently from a generator that burns fuel until the tank is empty. See battery versus generator for outages and why solar alone goes dark in an outage.

Job two: bill savings, and why NEM 3.0 changed them

Savings depend on the tariff your solar is on. The CPUC says NEM 1.0 and NEM 2.0 credit exports at retail rates. If a noon export is worth about what you pay at night, storing it gains little, so on those accounts a battery is mainly a backup purchase.

Net billing, NEM 3.0, is different. The CPUC says export credits there are based on its Avoided Cost Calculator and are usually lower than the retail rate, and it reports that nearly 70 percent of net billing customers had paired a battery with solar by the end of 2024. PG&E’s price sheet for 2026 applicants shows about $0.0085 per kWh for a weekday noon export in April and about $1.15 at 7 p.m. on an August weekday. A battery that charges from midday solar and covers your evening use avoids buying power at peak prices instead of exporting it for pennies. Run your own numbers with the NEM 3.0 battery payback guide and the hourly export values.

Is solar plus storage worth more with SCE, PG&E or SDG&E?

The value of storage is the gap between what an export earns at midday and what you would pay for the same kWh in the evening. Each utility puts net billing customers on a different rate, so the gap differs.

• SCE. Solar Billing Plan customers take TOU-D-PRIME. SCE lists 59¢ per kWh on summer weekdays from 4 to 9 p.m. and 26¢ off-peak. Its 2025–26 examples put summer daytime exports at about $0.06 and 4–9 p.m. exports at about $0.21. Details are on the SCE Solar Billing Plan guide.
• PG&E. Net billing customers take E-ELEC. PG&E’s current rate table lists about 55¢ per kWh at the summer 4–9 p.m. peak and about 33¢ off-peak. See the PG&E Solar Billing Plan guide.
• SDG&E. Net billing customers take EV-TOU-5. SDG&E’s August 2026 table lists about 80¢ per kWh summer on-peak and 13¢ super off-peak. SDG&E residential net billing customers get no export bonus, because the CPUC found their paybacks were already under nine years without it. See SDG&E net metering and the Solar Billing Plan.

Customers of LADWP and other city utilities are not on NEM 3.0 at all, which changes the math; see how LADWP net metering works.

Battery storage versus staying on the grid

Without a battery, a net billing home buys its evening power from the grid and exports its midday surplus at the avoided-cost value. With one, some of that surplus covers the evening instead. Both homes still pay their utility’s fixed monthly charges, which export credits cannot offset. And both lose power in an outage unless the battery is set up for backup. Ask a bidder to show your bill three ways from the same twelve months of usage: no solar, solar alone, and solar with storage.

What a solar battery costs in California

No manufacturer publishes a California installed price, so the best primary benchmarks are Lawrence Berkeley National Laboratory’s. Its Tracking the Sun 2024 report found storage added roughly $750 to $1,000 per kWh to the installed price of paired residential systems in 2023. Its 2026 data update found the median home battery installed in 2025 was 13.5 kWh, based about 80 percent on California data, and that among cash purchases, paired solar-plus-storage systems had a median price $2.1 per watt higher than solar alone.

At $750 to $1,000 per kWh, 13.5 kWh adds about $10,000 to $13,500. Your price moves with the number of units, whether the main panel needs an upgrade, the backup gateway or critical-loads panel, the permit, and how far the battery sits from the panel. For a line-by-line build, see home battery cost in California.

California battery storage: how fast it is growing

The California Energy Commission reported in August 2026 that battery resources serving the state now total 21,112 MW. About 3,000 MW of that comes from more than 300,000 smaller systems at homes, schools, farms and businesses. The rest is utility-scale, including about 2,000 MW in Nevada and Arizona that serves the California grid.

On the question of Texas overtaking California, the CEC says Texas has a similar amount of total installed battery capacity but its systems typically discharge for two hours or less, while California’s fleet is dominated by four-hour batteries. At home, Berkeley Lab found residential storage attachment rose nationally from 25 percent of solar installs in 2024 to 37 percent in 2025, driven largely by California. The statewide numbers are broken down in California battery storage capacity.

Can you get a solar battery at no cost?

Some households can, through programs with strict eligibility and limited supply. None is open to everyone, and most were full or nearly full when checked on September 23, 2026.

PG&E’s Residential Storage Initiative installs a battery, typically 10 to 13 kWh and valued at over $15,000, at no charge. It requires an EPSS-impacted circuit, five or more EPSS outages since January 1, 2024, and enrollment in CARE, FERA, Medical Baseline or the Self-Identified Vulnerable program. PG&E says its 2026 supply is almost gone. Its Reliability Battery Initiative, which installs 10 to 15 kWh on less reliable circuits, is full for 2026. SCE’s Critical Care Backup Battery program provides a portable battery, not a home system, to Medical Baseline customers in high fire risk areas who rely on powered medical equipment.

Anything else sold as a no-cost battery deserves a close read. A lease, a PPA or a loan with no money down still has a monthly payment. Ask who owns the equipment and what you owe over the term.

Residential Solar and Storage Equity: the income-qualified budget

The Self-Generation Incentive Program’s Residential Solar and Storage Equity budget is the state’s largest battery incentive for lower-income homes. The CPUC says it holds $280 million from the state’s Greenhouse Gas Reduction Fund and pays $1.10 per watt-hour of storage and $3.10 per watt of new solar. The 2026 SGIP Handbook’s own example shows how that adds up: a 13.2 kWh battery and a 5 kW solar array reach a maximum incentive of $30,020, though the actual award can be lower.

For a single-family home, the handbook requires household income at or below 80 percent of area median income, or income already verified through CARE, FERA, the Energy Savings Assistance program, SASH or DAC-SASH. Only new solar qualifies, not an expansion of an existing array. Renters can apply with a letter of approval from the owner, and customers of city utilities and rural co-ops are eligible too.

Funding is the catch. On September 23, 2026 the program tracker showed the budget open only for customers of publicly owned utilities assigned to PG&E or SCE, and waitlisted for everyone else. The handbook sets June 30, 2028 as the last day for new and waitlist applications. The budget-by-budget status, and which administrator handles your utility, are on the SGIP battery rebate status page.

Other programs and rebates still running in 2026

The biggest help is gone: the IRS says the residential clean energy credit is not allowed for expenditures made after December 31, 2025. What remains is aimed at specific households. PG&E customers with five or more Wildfire Safety outages since January 1, 2024 may qualify for PG&E’s Permanent Battery Storage Rebate,$7,500 for first-time battery owners. PG&E showed 179 rebates left as of September 18, 2026, with a December 31, 2026 deadline. The full PG&E list is on PG&E’s battery incentives page.

Before signing, check who will install it and how the warranty works if that company closes; see how to choose a solar battery company. Commercial projects follow separate rules on the commercial storage and SGIP page.