SAN FRANCISCO, CA · BATTERY
Battery energy storage systems in San Francisco.
We size, permit, install, and commission commercial battery energy storage systems for San Francisco buildings, then keep them tuned after startup.
Storage that pays for itself.
Commercial batteries earn their keep two ways: shaving the demand peaks that drive your bill, and carrying the building through outages that used to cost you a day. Request pricing on install battery energy storage systems from a single cabinet to containerized BESS on a pad.
The unglamorous parts are where projects die, so price them up front: utility interconnection, permits, NFPA 855 compliance, and commissioning. Pairing with solar or EV charging? One design, one crew, one number.
START HERE
What San Francisco facility teams should know before buying commercial battery storage
A battery energy storage system stores power in your building and sends it back out when electricity costs the most or when the grid drops. In San Francisco, we size, permit, install, and commission these systems for commercial buildings. Every job starts with a year of meter data, not a catalog page. California law now sets the clock. AB 1373, signed February 7, 2026, requires commercial buildings over 50,000 square feet to install battery storage by January 1, 2029, with at least two hours of average peak demand. We help San Francisco owners plan the build well ahead of that date.
AB 1373 gives San Francisco buildings over 50,000 sq ft until January 1, 2029
AB 1373 was signed on February 7, 2026. It requires every commercial building over 50,000 square feet in California to install battery energy storage by January 1, 2029. The minimum capacity is two hours of average peak demand. Indoor installations must carry UL 9540A certification. It is the first law in the country to mandate storage in existing commercial buildings. Two decisions come first for San Francisco owners. Pull your average peak demand, because that number sets the minimum kWh. Then choose indoor or outdoor, because indoor drives the UL 9540A listing and the fire review. CalFire is developing a fast-track permit process for indoor systems, expected in Q3 2026.
Permit path
How we permit battery energy storage systems in San Francisco
San Francisco DBI plan review
PERMIT
The Department of Building Inspection reviews every building permit application for life safety and building code compliance. We submit the electrical, structural, and fire drawings as one package so review does not stall on a missing sheet.
Pick the right filing route
FILING
San Francisco offers more than one way to apply, depending on the project. We confirm the route with DBI permit services before we publish an install date, because the route decides how long approval takes.
JURISDICTION
ssf. net, or at the counter Monday through Friday, 8am to 4pm, closed noon to 1pm. Different reviewer, different queue, different schedule.
Indoor room or outdoor pad
FIRE CODE
AB 1373 requires UL 9540A certification for indoor installations. Choose the location before drawings start, since indoor pulls in the fire review and the CalFire fast-track path expected in Q3 2026.
PROJECT PLANNING
What battery energy storage systems return for San Francisco commercial buildings
Demand charge reduction
DEMAND CHARGES
California commercial demand charges run $15 to $25/kW. Cutting peak demand 30% to 50% saves a typical commercial facility $50,000 to $200,000 a year, which is usually the largest line in the model.
Time-of-use arbitrage
RATE TIMING
The battery charges when midday supply is long and discharges into the evening peak.
Backup power
RESILIENCE
Sized against your critical panel, the system carries elevators, controls, refrigeration, or servers through an outage instead of shutting the building down.
Grid services and IRR
IRR
Grid services revenue stacks on top of the savings. Combined, these streams typically deliver 15% to 20% IRR on commercial storage in California.
WHAT WE HANDLE
Everything under the battery door.
Sizing inputs
How we size a battery energy storage system for a San Francisco facility
- Twelve months of interval data from your meter: the kW peaks set the power rating, the kWh set the runtime.
- Your average peak demand, since AB 1373 sets the floor at two hours of that number for buildings over 50,000 square feet.
- Your demand charge in dollars per kW. California commercial rates run $15 to $25/kW, and cutting peak demand 30% to 50% is what pays the system back.
- Backup priorities: which panels, elevators, and equipment must ride through a PG&E outage, planned or unplanned.
- Cycle plan against warranty. Lithium-ion units carry 10-year warranties and 4,000 to 6,000 cycles, so daily rate arbitrage plus backup duty has to fit inside that budget.
BEFORE YOU BUY
Questions to ask before signing a battery storage contract in San Francisco
- What kW and kWh did you size from, and can you show the interval data behind those numbers?
- Does the proposal meet the AB 1373 floor of two hours of average peak demand?
- Is the equipment listed to UL 9540A, and does the report cover the indoor room we plan to use?
- Does the 10-year warranty cover capacity retention, cycle count, or both, and what voids it?
- Who files with San Francisco DBI, and who carries the cost if plan check sends drawings back?
- Who tunes the dispatch settings after the first month of live billing data?
Project in San Francisco?
Tell us the building, exact scope, and target date. Flux will review the request and send the next step.
QUESTIONS
Straight answers.
Does my San Francisco commercial building have to install battery storage?
If it is a commercial building over 50,000 square feet in California, AB 1373 requires battery energy storage by January 1, 2029. The law covers an estimated 47,000 buildings statewide.
How large does a battery energy storage system have to be in San Francisco?
AB 1373 sets a floor of two hours of your average peak demand. We size from a year of meter data, because backup loads and demand savings often push the system above that floor.
Can the battery go inside the building?
Yes, if the equipment carries UL 9540A certification, which AB 1373 requires for indoor installations. CalFire is developing a fast-track permit process for indoor systems, expected in Q3 2026.
Who reviews battery storage permits in San Francisco?
The Department of Building Inspection reviews every building permit application for life safety and code compliance.
GET STARTED
See what storage does to your bill.
Twelve months of bills is all the modeling needs. We'll show the demand-charge math for free, and tell you straight if it doesn't pencil.
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