Thermal Runaway Is Not a Risk You Can Insure Away.

In industrial safety engineering, there is a hierarchy of risk controls that has been standard practice for decades. At the top of that hierarchy sits elimination: removing the hazard entirely. Substitution, engineering controls, administrative controls, and personal protective equipment follow in descending order of effectiveness. The hierarchy exists because downstream controls fail. Suppression systems are not activated in time, administrative procedures are not followed under pressure, and insurance claims — paid after the event — do not restore destroyed property or compensate for operational continuity losses.

Applied to battery energy storage, this hierarchy has a clear implication. The most reliable response to the thermal runaway risk associated with lithium-ion chemistry is not a more sophisticated fire suppression system or a more comprehensive insurance policy. It is a storage technology that cannot experience thermal runaway in the first place. That is not a counsel of perfection. It is the engineering logic that underlies 247 Energy's product design philosophy.

"Suppression systems are not activated in time. The hierarchy of controls is unambiguous: elimination is the only complete solution to a hazard." Understanding the failure mode Thermal runaway in lithium-ion cells begins with a trigger: overcharging, mechanical damage, internal short circuit, or exposure to elevated temperatures. The trigger initiates exothermic chemical reactions within the cell that generate heat faster than it can be dissipated. Adjacent cells, heated by the first, enter the same process, creating a self-propagating reaction across the module and potentially across the battery rack. At elevated temperatures, cells emit flammable gases including hydrogen, which can ignite and sustain a fire that is extraordinarily difficult to extinguish using conventional agents. Lithium-ion fires have been recorded at durations exceeding 24 hours, requiring specialist suppression approaches and producing toxic smoke at concentrations that require site evacuation.

The frequency of serious BESS incidents is rising as installed capacity grows. Research published in the International Journal of Electrical Power and Energy Systems in 2026 documents the escalating frequency and operational impact of cyberattacks on energy infrastructure between 2022 and 2025, but physical failure incidents follow a similar trajectory. The more lithium-ion capacity is installed, the more thermal runaway events occur, even as cell quality and battery management systems improve. The absolute risk rises with scale.

The regulatory response European regulators and building authorities have begun updating guidance to reflect the thermal runaway risk in occupied and adjacent-to-occupied structures. Several jurisdictions now require minimum setback distances between lithium-ion BESS installations and building boundaries, mandatory gas detection systems, dedicated suppression agents, and, in some cases, structural fire containment barriers. These requirements add cost and constrain installation locations in ways that were not anticipated when the original project economics were modelled. Projects designed before the updated guidance was published are discovering that compliance retrofitting significantly exceeds original contingency estimates.

"Regulatory guidance is tightening around lithium-ion installations in occupied structures. Projects designed before the updates were published are discovering that compliance retrofitting is expensive." Supercapacitor technology, which stores energy electrostatically rather than through electrochemical reactions, does not produce the exothermic chain reactions that drive thermal runaway. A supercapacitor cell that is overcharged, mechanically damaged, or exposed to elevated temperature does not self-propagate failure to adjacent cells. The failure mode that drives the regulatory complexity and insurance challenge of lithium-ion installations simply does not exist. This is not a marginal safety improvement. It is the elimination of the hazard at the top of the control hierarchy.

247 Energy's SuperCap product range is designed around this principle. The clients who have installed it in occupied logistics warehouses, manufacturing facilities, and commercial buildings have done so knowing that the thermal runaway risk they were eliminating from their sites was a real operational and financial exposure, not a theoretical concern.