More than a fence. Battery energy storage needs enclosures, spacing and a response plan that keep a thermal or intrusion event contained, because the consequence of a failure depends on whether it spreads.
Grid-scale battery storage has grown faster than most of the rules written for it. EPRI's analysis of its failure incident database found global deployment rose from about 1 GW in 2018 to 65 GW in 2023 while the number of incidents stayed near ten a year. Over that period, EPRI reported, the failure rate for grid-scale systems fell 97 percent. That is real progress. It is also a reminder that the failures that remain are concentrated, and that a single one can be very large.
What Moss Landing showed
On January 16, 2025, fire broke out in the 300 MW battery building at Vistra's Moss Landing site in California, which holds about 100,000 lithium-ion batteries. EPA reports that about 55 percent of them were damaged, and describes the cleanup as the largest lithium-ion battery cleanup in the agency's history. About 1,200 residents were ordered to evacuate. As of January 2026 the cause investigations were still open, and in September 2026 a new fire broke out in the damaged area while removal continued.
The lessons that are already clear do not depend on the final cause. The battery units were housed inside a building, so a fire in one area had a path to others. Response depended on protecting the surrounding community rather than on containing the event quickly. And the consequence ran for more than a year after the first day.
Where failures start
EPRI's data points away from the cells themselves as the usual starting point. Of the incidents in its database with a determined root cause, only about 11 percent traced directly to the cells. Seventy-two percent of failures where system age was known happened during construction, commissioning or the first two years of operation. That makes installation quality, integration and early operation the periods that deserve the most attention.
What the standards now ask
NFPA 855, the Standard for the Installation of Stationary Energy Storage Systems, was reissued in a 2026 edition in September 2025. The new edition adds large-scale fire testing and new requirements for project emergency response plans, along with provisions on thermal-runaway propagation protection and explosion control. At the local level, New York's model local law for storage siting calls for a fence, suggested at seven feet, with a self-locking gate around larger systems unless they are housed in a dedicated building, and requires an emergency operations plan.
Physical attack gets less attention in those documents than fire. Sandia's chapter on physical security for energy storage fills the gap. It names the vital targets, which are the battery systems, HVAC, transformer stations, control buildings and overhead bus, and lists rifle fire, sniper, arson and vehicle threats, citing the Metcalf substation attack. Its recommendations are layered access control with thermal cameras and motion sensing, and the same detection-before-delay logic used at substations.
Designing the enclosure as the control
- Compartmentalize. Separation between units, and between the battery and the control building, is what keeps one event from becoming a site-wide loss.
- Protect the control room and the HVAC. Losing thermal management or monitoring can start the event an attacker could not.
- Block line of sight to critical components. The substation attacks were carried out from outside the fence.
- Plan the first two years. Commissioning and early operation carry most of the recorded risk, so inspection and acceptance testing belong in the contract, not the warranty.
- Write the response plan with the fire service before construction. The 2026 edition of NFPA 855 adds requirements for project emergency response plans.
A battery yard's risk profile is set by what happens after the first failure. Enclosure, spacing and response planning are the controls that decide whether the story ends at one unit.
Sources
- EPRI, BESS Failure Incident Analysis (May 2024)
- EPRI Journal, An Untold Success Story
- U.S. EPA, Moss Landing Vistra Battery Fire
- Utility Dive, Moss Landing battery fire (Jan. 21, 2025)
- KAZU, What we do and don't know a year after the Moss Landing fire (Jan. 16, 2026)
- CBS News Bay Area, Moss Landing fire (Sept. 18, 2026)
- Energy-Storage.News, NFPA 855 2026 edition released
- NYSERDA, New York Battery Energy Storage System Guidebook
- Sandia National Laboratories, DOE Energy Storage Handbook, Ch. 18
Cite this article: Authentic Intelligence Research, “What Protection Does Grid-Scale Energy Storage Need?” Authentic Intelligence, September 30, 2026, https://authenticint.com/articles/energy-storage-needs-protective-building-materials.html.