BESS Construction Guide: Battery Storage and the Fire Code

Part of "How It Gets Built" — Buildermuse's series on the machinery behind modern construction.

U.S. power providers added a record 15 gigawatts of utility-scale battery storage in 2025, according to the U.S. Energy Information Administration, up from 10.3 GW in 2024. By the end of 2025, operating battery capacity stood at 43.6 GW. Operators added another 8.3 GW in the first half of 2026, bringing the total to nearly 52 GW, and EIA reported on August 7, 2026 that operators plan about 54 GW more over the next two and a half years: 14 GW in the second half of 2026, 26 GW in 2027 and 14 GW in 2028. EIA says battery capacity has grown at an average annual rate of 70 percent over the past three years.

That is a construction category, not a niche. It is also one where the fire code, more than the electrical drawings, often decides how long permitting takes. Contractors who understand Section 1207 of the International Fire Code and NFPA 855 move through plan review faster than those who treat a battery yard like a routine electrical job.

An earlier version of this article cited 12.3 GW of 2024 additions, a $25 billion annual investment figure, NREL installed costs of $236 to $340 per kWh, specific NFPA 855 spacing and setback numbers, equipment lead times, crew sizes, wage ranges and permitting timelines. Several of those figures conflict with EIA data or could not be traced to a source, so they have been removed or replaced.

Where the Work Is

EIA's February 20, 2026 outlook said developers planned 24 GW of utility-scale battery additions in 2026, concentrated in three states:

State	Planned 2026 battery additions	Share
Texas	12.9 GW	53%
California	3.4 GW	14%
Arizona	3.2 GW	13%

Individual projects are getting larger. EIA's August 2026 article names the 500 MW of storage at the Bellefield Solar and Energy Storage Farm in California, operating since December 2025 and planned to double by November 2026, which would make it the largest storage facility in the country. It also lists Florida's Manatee Solar Energy Center (409 MW of batteries, operating since 2021) and Nevada's Gemini Solar Hybrid (380 MW of storage, operating since 2024). Many new batteries are being built alongside solar plants, which means BESS scopes often arrive inside larger solar EPC contracts.

What a Utility-Scale BESS Site Is

Strip away the acronyms and a grid-scale battery project is a fenced yard of factory-built enclosures, set on foundations, wired together through inverters and medium-voltage transformers, and tied into a substation. The scope breaks down by trade roughly like this:

• Civil. Clearing, grading, stormwater controls, access roads that can carry crane and delivery loads, and foundations for enclosures, inverters and transformers. Enclosure foundations have to be set accurately because door openings and bus connections depend on alignment.
• Electrical. DC connections from battery enclosures to power conversion systems, medium-voltage collection circuits, step-up transformers, grounding, protection and the substation or switchyard interconnection. Electrical is the center of gravity on most BESS jobs. Our substation construction cost article covers the interconnection end of the work.
• Fire protection and detection. Gas and smoke detection, any suppression the design requires, fire water supply where the fire department demands it, and the explosion control hardware described below.
• Mechanical. HVAC or liquid cooling that keeps cells in their operating range, usually integrated in the enclosure by the manufacturer but connected and commissioned on site.
• Controls and communications. The energy storage management system, site SCADA, fiber and the utility's telemetry.

The battery enclosures are usually owner-furnished equipment on a fixed delivery schedule, and large power transformers are long-lead items. That flips the normal sequence: the contractor builds toward delivery dates set before civil design is finished. A missed pad-ready date means storage and rehandling costs on very expensive equipment.

What it costs

Installed cost depends heavily on duration, region, interconnection scope and equipment pricing, and it has moved quickly. For a long-term reference point, EIA's Annual Energy Outlook 2023 cost assumptions (March 2023) used an overnight capital cost of $1,270 per kW for a 50 MW battery storage plant, in 2022 dollars. Treat that as a modeling assumption rather than a bid price, and note that tariffs and cell prices have changed since. For current numbers, rely on actual bids and owner budgets in your market.

The Code Framework: IFC 1207 and NFPA 855

Two documents govern how stationary battery systems are permitted. Section 1207 of the International Fire Code covers electrical energy storage systems, and NFPA 855, the Standard for the Installation of Stationary Energy Storage Systems, covers the same ground in more detail. Many jurisdictions adopt both. Clark County, Nevada's fire department, for example, lists the 2024 IFC, its own 2024 amendments and the 2023 edition of NFPA 855 as the applicable codes in its January 2026 permit submittal guide for permanent ESS.

When a permit is required

IFC Table 1207.1.3 sets the energy capacity above which ESS rules and an operational permit apply. As reproduced in the Clark County guide, the threshold is 20 kWh for lithium-ion batteries and flow batteries, 70 kWh for lead-acid and nickel-based batteries, and 3 kWh for capacitor ESS and "other" battery technologies. Every utility-scale project is far above those thresholds, so the full Section 1207 package applies.

What fire officials ask for

Clark County's submittal guide is a useful checklist of what an authority having jurisdiction (AHJ) expects:

• Project information including the energy technology and the energy capacity of individual units and of the whole system
• A site plan showing distances between units and to lot lines, public streets and ways, other buildings and building openings
• Signage, security (fencing, bollards) and vehicle impact protection
• The full UL 9540A report or large-scale fire test report, plus a failure modes and effects analysis if the test report does not cover it
• Equipment listing, the energy storage management system, commissioning and decommissioning reports, and fire detection and suppression details

For installations in buildings, the same guide notes a 2-hour fire separation requirement, and for rooftops and parking garages it requires radiant energy sensing fire detection.

UL 9540 and UL 9540A

UL 9540 is the product safety standard that ESS equipment is listed to. UL 9540A is different: it is a test method, not a pass/fail certification. It forces cells into thermal runaway and documents heat release, gas generation and whether fire propagates at the cell, module, unit and installation levels. Fire protection engineers and AHJs use that data to justify unit spacing, explosion control design and suppression choices for the exact product being installed. When the test data is missing or covers a different product, the AHJ falls back on the code's default limits and conservative layouts.

Explosion control

Lithium-ion cells in thermal runaway release flammable gases. The code response is explosion control: either deflagration venting designed under NFPA 68 or explosion prevention by ventilation and gas detection under NFPA 69. Many enclosures arrive with manufacturer-integrated vent panels or exhaust systems, but the installation still has to be approved by the AHJ, which wants calculations tied to that product's 9540A gas data. Check that the cell, module, unit, test report and calculations all describe the same product before mobilization.

Why the Fire Service Takes This Seriously

Two incidents shaped how fire officials review battery projects.

On April 19, 2019, a deflagration at a 2.16 MWh lithium-ion battery facility in Surprise, Arizona (the McMicken site) severely injured four career firefighters with specialized hazardous materials training. UL's Fire Safety Research Institute investigated and released its report on July 28, 2020. FSRI notes that the system was commissioned before the first draft of NFPA 855 was released and complied with the codes in effect at the time.

On January 16, 2025, fire broke out in one of the battery buildings at Vistra's Moss Landing Power Plant in Monterey County, California, a facility that can store up to 750 megawatts according to a Vistra release cited by KQED. KQED reported that more than 1,000 Moss Landing residents were evacuated, that nearly 40 percent of the building was destroyed, and that a county supervisor called it the fourth fire at the site since 2019. The California Highway Patrol closed Highway 1 around the plant, E&E News reported. The fire involved batteries housed inside a building, a different design from the outdoor containerized enclosures most new projects use, but it raised the political temperature around siting everywhere.

The practical effect for contractors is more scrutiny at plan review: AHJs asking for complete 9540A data, third-party fire protection engineering review, emergency response plans and coordination with the local fire department before energization. Developers that bring a complete safety package to the first pre-application meeting tend to move faster.

Workforce and Safety

Electricians do most of the hours on a battery site. BLS OEWS data put the national median wage for electricians at $30.38 an hour in May 2025, and our electrician wages by state page breaks that down by market. Utility-scale DC work at high voltage also calls for NFPA 70E arc flash training and qualified-person procedures, and manufacturers often require their own installation and commissioning certifications.

One safety point deserves plain language. Stored energy does not go away when a breaker opens. A battery at a partial state of charge still holds dangerous energy, cells damaged in shipping can fail later, and flammable gas inside a sealed enclosure is invisible. Gas monitoring before entry, written lockout procedures for DC systems, and an emergency plan the crew has actually practiced belong on every BESS job.

BESS is not battery manufacturing

Do not confuse this market with battery factory construction. Cell and pack plants are large industrial buildings; we cover them in our EV battery plant construction report. Battery storage sites are horizontal, outdoor and electrical-heavy, and the trades, contracts and codes barely overlap.

Your Action Item for This Week

Find out which edition of the IFC and NFPA 855 your local fire marshal enforces, and ask whether the office has a written ESS submittal checklist like Clark County's. Then look at EIA's planned-capacity data for your state and the interconnection queue of your regional grid operator. A short list of nearby storage projects, matched with the submittal requirements your AHJ actually uses, is a better prospecting tool than any generic market forecast.

Frequently Asked Questions

How much battery storage is being built in the U.S.?

EIA reports a record 15 GW of utility-scale battery storage added in 2025, following 10.3 GW in 2024. Operating capacity was 43.6 GW at the end of 2025 and nearly 52 GW by mid-2026, and operators plan about 54 GW more through 2028 (14 GW in the second half of 2026, 26 GW in 2027 and 14 GW in 2028).

Which states are building the most battery storage?

In EIA's February 2026 outlook, Texas accounted for 12.9 GW (53 percent) of planned 2026 additions, California 3.4 GW (14 percent) and Arizona 3.2 GW (13 percent).

Which fire codes apply to battery energy storage construction?

Section 1207 of the International Fire Code and NFPA 855. Jurisdictions adopt specific editions; Clark County, Nevada, for example, applies the 2024 IFC and the 2023 edition of NFPA 855. Under IFC Table 1207.1.3, lithium-ion systems above 20 kWh fall under the ESS requirements.

What is UL 9540A and why do fire marshals ask for it?

UL 9540A is a test method that drives battery cells into thermal runaway and documents fire and gas behavior at the cell, module, unit and installation levels. AHJs use the report to evaluate spacing, explosion control and suppression for the specific product. Clark County's permit guide requires the full 9540A or large-scale fire test report with the submittal.

Did the Moss Landing fire stop battery storage construction?

No. EIA data show record additions in 2025 and more planned for 2026 through 2028. The January 2025 fire did increase scrutiny of siting and safety documentation during local permitting.