BESS | Frequently Asked Questions

Battery fires are relatively rare when compared to the number of installations. The Electric Power Research Institute (EPRI) [1] maintains a database of fires involving BESS, and identified 15 events globally in 2023, compared to 12 events in 2022.

Within Europe, the EPRI database lists 10 total reported incidents to date (earliest reported incident in November 2017). To add context, 170 grid-scale battery energy storage (of which the majority were lithium-ion) were deployed across Europe in 2022 [2].

The following detection systems are relevant to a fire scenario:

• The battery management system (BMS) – this is likely be the first system to detect an abnormal condition in a module.
• Smoke and heat detection
• Gas detection – this can be used to detect gas such as carbon monoxide released from chemical reactions during overheating of cells  

Most BESS are operated remotely, however an Emergency Response Plan prepared in advance ensures that anyone working on site are aware of recommended actions to protect themselves and others in an incident.

In a fire, first responders must be prepared for hazardous thermal exposures. An Emergency Response Plan prepared in advance ensures that first responders are aware of recommended actions to protect themselves, such as recommended setback distances, firefighting strategy, and personal protective equipment (PPE).

As well as design measures within the BESS containers themselves, dangers from fire to the public are minimised by the design of the site, including separation distances sufficient to prevent fire spread. Barriers such as fire-rated construction may also be provided. For a specific site, the separation distance and/or fire-rated construction would be established and justified by a Hazard Mitigation Analysis (HMA). Statkraft conducts an HMA for each BESS installation.

Emergency fire and rescue services will determine a suitable firefighting strategy. One example strategy is to apply water to adjacent (non-burning) BESS and structures to prevent fire spread. If it is deemed necessary and safe, manual water-based suppression to the burning BESS may also be applied. In some cases, letting the affected BESS burn in a controlled manner may be the safest approach.  

This would be determined by the emergency fire and rescue services. In most instances, no public response is deemed necessary with the BESS fire being deemed to pose no significant hazard to the public. In cases where actions are recommended, the emergency fire and rescue services would advise members of the public of recommended actions such as closing windows and shelter in place, or in extreme cases evacuation. 

Incident investigation is typically initiated while the incident is still active or shortly after its conclusion. The objective of the investigation is to determine the root causes and contributing factors that led to the incident to allow measures to be established to prevent it repeating, and to determine extent of any contamination.

An appropriate incident investigation is led by a qualitied professional. Operational data is collected and analysed and information gathered from site operatives, first responders, and subject matter experts.

Generally, incident investigations also include the development of site-specific and general industry recommendations to prevent or minimise such incidents. In line with good practice, each site-specific recommendation is assigned a responsible party and targeted completion date.  

Battery fires are relatively rare when compared to the number of installations. The Electric Power Research Institute (EPRI) [1] maintains a database of fires involving BESS from media reporting sources. Over the full timespan covered by the EPRI database (November 2011 to date), only 6 explosion incidents have been reported globally, of which 3 such incidents occurred in Europe (UK, Sweden, and France).

It is worth noting that symptoms of historic BESS container fires are not necessarily representative of current technologies, due to lessons learnt from previous incidents resulting in changes in BESS container design and emergency response approach.

The Gas detection system will detect the presence of flammable gases before they approach flammable concentrations. Explosion prevention systems can include ventilation designed to maintain the gases below explosive concentrations.

Modern BESS designs have been adapted using lessons learnt from previous BESS incidents: battery containers should not allow operatives to enter the units, and emergency response strategies should ensure no manual opening of containers until confirmed safe to do so. To the best of our awareness, no physical injuries to the public have been Identified from the reported BESS explosion incidents in industry (as reflected in the EPRI database).

BESS layout design is informed using test data that characterises BESS behaviour in conditions associated with explosions to ensure that appropriate unit placement and offsets between equipment is specified according to relevant standards (such as NFPA 855). Explosion prevention systems can include ventilation designed to maintain gases below explosive concentrations.