Get the Facts on
Battery Storage Safety
Battery energy storage is keeping the lights on across the West — and today's systems are built to a standard the first generation never had. Here's the evidence behind the headlines.
Storage Is Surging — And Getting Safer
Deployment has grown sharply while incidents per gigawatt have fallen. Safety and scale are moving in the same direction.
Global Grid-Scale Storage Deployment & Failure Statistics
Deployment has climbed sharply while failures per gigawatt-hour have collapsed.
Sources: (1) EPRI Failure Incident Database; (2) Wood Mackenzie, Global Energy Storage Outlook. Data as of 12/31/24.
What Changed Since the Early Systems
The 2019 fire in Surprise, Arizona drove a wave of new standards, designs, and emergency practices. The contrast with how systems are built today is stark.
Comparison adapted from The Western Way's "Get the Facts of BESS Safety" one-pager.
Four Layers of Protection
Today's installations don't rely on any single safeguard. They stack independent layers, each governed by national codes.
Spacing & Separation
NFPA 855 and the International Fire Code set minimum spacing between containers — reduced only after large-scale fire testing and approval by the local authority. The result: fires are largely confined to a single container.
Testing & Detection
UL 9540 listing and UL 9540A fire-propagation testing are now expected. Sensor networks and analytics monitor cell temperatures and flag the earliest signs of trouble for proactive intervention.
Pressure Management
Deflagration-management strategies — exhaust ventilation and pressure-sensitive panels that open automatically — relieve the buildup of heat and gases before it can become an explosion hazard.
Runaway Prevention
Fire-retardant materials insulate modules from one another, fire safety systems carry hours of backup power, and every system includes deflagration protection under NFPA 68 and/or NFPA 69.
The Standards That Govern Battery Storage
Like pipelines, refineries, and gas stations, battery storage operates under an overlapping series of codes and regulations — not on the honor system.
The foundational installation standard for stationary storage — covering thermal-runaway mitigation, detection, and explosion control.
Evaluates the integrated system's electrical, mechanical, and thermal safety. NFPA 855 requires every BESS to be listed to it.
The test method for evaluating how thermal runaway propagates — the data behind containment and prevention design.
Deflagration relief panels and combustible-gas reduction systems that prevent an explosive atmosphere from forming.
The International Fire Code and National Electrical Code set fire-safety and electrical requirements adopted by jurisdictions nationwide.
Federal workplace safety standards governing the installation, operation, and maintenance of storage systems.
What the Experts Are Seeing
"The global installed capacity of utility-scale battery energy storage systems has dramatically increased over the last five years. While recent fires have garnered significant media attention, the overall rate of incidents has sharply decreased, as lessons learned from early failures have been incorporated into new designs and best practices."
— Electric Power Research Institute, 2024
Skyrocketing growth of energy storage is making the U.S. power grid more reliable
America's power grid is astonishingly complex: the electricity generated at one end must always equal the amount consumed at the other, every second of every day. Storing power to use later makes that balancing act far easier — and the technology is hitting its stride.
In 2018, less than one gigawatt of battery storage was connected to the grid. By 2025, the U.S. surpassed 30 gigawatts, with Arizona ranking third in the nation. The biggest driver is falling cost: grid-storage lithium-ion prices have dropped roughly 8% a year for a decade.
As costs fall, the reliability payoff is becoming clear. A closely watched report on North American grid stability found reliability improvements in areas with high concentrations of battery storage — even as demand from data centers and severe weather strained the wider system.
Andy Tobin · Director, Arizona Rural Energy Network, The Western Way
Read the full piece →Resources for Decisionmakers
Share these with neighbors, officials, and local leaders weighing battery storage in their community.
Safety Improvements in Long-Duration Battery Storage
A summary for decisionmakers covering the regulatory frameworks, design changes, and data behind the safety record.
Read the ReportGet the Facts of BESS Safety
A side-by-side look at what changed between the early systems and modern BESS — and the standards driving each improvement.
View the One-Pager