House of Commons Debate on Battery Energy Storage Site Safety Regulations
Date: 5 June 2025
Debate Location: Westminster Hall Lead MP: John Milne MP (Liberal Democrat, Horsham)
1. Introduction
This report summarises the key issues raised during the House of Commons debate held on 5 June 2025, concerning the safety of Battery Energy Storage Systems (BESS). The debate focused on the lack of national safety regulations, fire risks including lithium-ion thermal runaway, and the inadequacy of current fire suppression and planning standards.
2. Inadequacy of Current Fire Suppression Systems
MPs expressed concern that many current fire suppression systems installed at BESS facilities are not designed to deal with thermal runaway or are untested. John Milne MP stated: “Some suppression systems currently being installed are not tested to deal with thermal runaway, or do not seek to prevent it at all.”
3. Preference for Water-Based Suppression and Off-Gas Monitoring
There was a clear preference among MPs and fire safety experts for water-based suppression systems, supported by off-gas monitoring and appropriate ventilation: “Fire safety experts now generally agree that the most appropriate fire suppression in these contexts is a water-based suppression system, with off-gas monitoring and appropriate ventilation.” “Suppression should be early, adequate and specifically engineered to prevent fire propagation from enclosure to enclosure.”
4. Deflagration and Explosion Hazards
The debate acknowledged the explosive potential of lithium-ion off-gases: “Off-gases can be explosive in the right concentrations, and there is a deflagration risk that is not always designed for.”
5. Firefighter Training and Emergency Response
Concerns were raised about inadequate emergency response capacity, particularly in rural areas served by retained firefighters: David Mundell MP: “The location of many of these sites are in rural areas, which are often served primarily by retained firefighters. They are a long way from where specialist firefighting resources would come from…” John Milne MP: “Even compulsory consultation is not enough by itself because the fire services themselves do not always have the expertise.”
6. Environmental and Public Health Risks
Thermal runaway events can lead to smoke, contaminated runoff, and environmental damage: “There are environmental risks—run-off into watercourses and pollution of soils—as well as toxic smoke and off-gases in the event of thermal runaway.”
7. Regulatory Uncertainty
Unclear accountability was highlighted. Milne noted confusion between the HSE and the Department for Energy Security and Net Zero: “No Department is ultimately responsible for this regulation…”
8. Key Recommendations from Parliament
– Mandate water-based fire suppression systems tested for lithium-ion fires.
– Require off-gas monitoring and active ventilation.
– Prohibit untested or inappropriate suppression technologies.
– Provide national firefighter training specific to BESS incidents.
– Introduce enforceable planning and siting standards.
– Implement environmental containment and remediation policies.
9. Conclusion
The motion was agreed without division, and Parliament has acknowledged the urgent need for enforceable regulations tailored to the specific risks of lithium-ion battery energy storage. This includes mandatory suppression systems, early detection, fire service preparedness, and environmental controls.