There’s fresh evidence that designers, installers, and operators of battery energy storage systems (BESSs) may hold the ultimate keys to BESS safety, a lingering concern amid publicity surrounding recent incidents involving explosions and fires.
A white paper from Electric Power Research Institute (ERPI) fingers installation-related processes and procedures generally rather than the batteries or the technology and how they were manufactured for a significant share of documented BESS failure incidents researchers deconstructed.
EPRI’s insight comes as BESS projects proliferate and worries continue about whether batteries are prone to failure and whether the technology is yet ready for prime time. Explosions and fires that can be particularly hard to control/suppress given battery chemistry and their frequent clustering in BESS deployments are a common byproduct of the types of failures EPRI studied.
The study challenges the lingering notion that their frequency has been increasing, but some recent BESS incidents have been particularly deadly and headline-grabbing, reigniting safety concerns and spurring calls for closer scrutiny.
Topping the list was an explosion and fire recently at a lithium-ion battery production facility in South Korea that killed 22 workers as it raced through the plant. Before that, a string of less lethal fires in New York sparked a state government investigation into the safety of battery storage. And lately, several BESS fires in quick succession in California prompted calls for a moratorium on projects in San Diego County. That measure was ultimately scrapped, but a stiffer permitting process aimed at reducing risk through closer attention to best practices in project planning and execution did advance.
The emphasis on the need for more careful and deliberate design, installation, integration and commissioning of projects to improve safety is a key takeaway from the EPRI study.
Identifying “integration, assembly & construction”; “operation”; and “design” as the primary root causes, in that order, of incidents it studied that required an emergency response to protect life and property, the paper spells out possible broad remedies for each (see Figure). Better workforce training and quality checks during commissioning and installation, along with system-level failure analysis prioritizing component interfaces can help prevent failures linked to integration, assembly, and construction. Operational failures can be mitigated by closer attention to the battery management systems, notably battery monitoring and analytics that can generate insightful trends and predictive analyses. And in the design sphere, risk can be reduced with compliance with the latest revisions of codes and standards that incorporate lessons learned; tailored hazard assessments; and robust sensoring and monitoring to anticipate failures linked to system design flaws.
In addition to discovering root causes of incidents, EPRI also looked at what specifically failed. Of 16 incidents in the last three years that could be categorized by failure type, each was due to either failure in controls, encompassing sensing, logic circuits and communications systems, or balance of system (BOS), defined as “busbars, cabling, enclosures, power conversion systems, transformers, fire suppression systems, HVAC, liquid cooling systems,” and the like. None were tied to battery cells or modules, though one in 2019 was in two in 2020 were.
Although the report’s conclusion calls out the finding that “the data challenges the widespread assumption that the lithium ion battery cell is the primary cause of failure,” and that “the BOS and controls were the leading causes of failure, with the cell having a relatively small number of failures attributed to it,” recent research by Clean Energy Associates doesn’t let battery makers off the hook. Of 1,300 manufacturing defects it identified, almost one-third were battery cell-related, and another quarter were related to battery module assembly.
As these studies were being released there was progress on the energy storage safety policy front. The American Clean Power Association in June published a model ordinance for jurisdictions interested in regulating energy storage from a safety perspective. It offers a slate of approaches that counties and municipalities could take in seeking to ensure that BESS projects proposed for their communities are as safe as possible. Its recommendations lean heavily on requirements and guidance established in the National Fire Protection Association safety standard for energy storage, NFPA 855.
