Reports of the Serious 2020 Explosion and Fire at the Liverpool, Carnegie Road Battery Energy Storage System (BESS) in Liverpool

Professor Sir David Melville CBE, CPhys, FInstP

We have recently received through an FOI request these previously unpublished reports by the Merseyside Fire and Rescue Service (MFRS). They are the first full reports of a major BESS incident in the UK and are highly significant and of direct relevance to the much greater dangers posed by the 700MWh battery proposed for the Cleve Hill development.

The Liverpool BESS was of only 20MWh capacity housed in four shipping containers, one of which had exploded damaging its neighbours and scattering debris over a range of up to 23m. Whilst there have been many such fires and explosions throughout the world, large scale BESS in the UK are still at the planning stage. These reports therefore provide official and timely insight into the dangers Faversham potentially faces if Cleve Hill goes ahead as expected to during 2022.

The Liverpool site is close to residential property with the associated hazards. This parallels the relative proximity of Cleve Hill to houses and the Primary School in Graveney, unlike many installations word-wide placed in remote locations.

Thermal runaway led to the total destruction of one container out of four, so about 5 MWh worth of storage produced a major explosion and an all-night fire. The concern is that this was an explosive destruction of a mere 5 MWh. At Cleve Hill we expect a 700MWh BESS.

The MFRS significant incident report recorded:

Significant Incident Report Incident no. 018965 Orsted BESS, Carnegie Road – February 2022 5 2 INCIDENT DETAILS: At 00:49hrs on 15th September 2020, MFRS Fire Control received numerous calls reporting a large explosion with smoke and flames visible in the vicinity of the Lister Fisheries and Pet Centre, Lister Drive, Tuebrook, near to Carnegie Road. Two appliances, from Old Swan fire station ''''''''''''''''''' '''''''''''''' and Liverpool City Centre fire station ''''''''''''''''''' ''''''''''''''''' were mobilised to the incident as per the predetermined attendance. On arrival, they discovered a large container unit fully involved in fire with evidence consistent of a blast. One of the container doors had been ejected from its setting and was laying some 6 metres away within the secure compound.

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The following are the major lessons noted in the reports:

1. MFRS concluded that the manufacturers’ operational risk information available for responding crews and the hazards associated with BESS was inadequate, highlighting a gap in ‘Site Specific Risk Information’ and a broader gap on the awareness and understanding of BESS sites and their inherent fire risks.
2. The Carnegie Road site is remotely managed and operated by Orsted who are based in Denmark, leading to delays in instigating switch off and electrical safety measures via Scottish Power.
3. The  Li-Ion cells of the BESS are susceptible to “thermal runaway” - the condition when an electro‐ chemical cell increases its temperature through self-heating in an uncontrollable fashion and progresses when the cell’s heat generation is at a higher rate than it can dissipate, potentially leading to off-gassing, fire, or explosion
4. Although an automatic fire alarm system was present and actuated due to the ignition of flammable gases inside the BESS unit. It did not prevent the fire or the ‘significant blast event’ (explosion).

• The result is evidently a Vapour Cloud Explosion caused by the use of a conventional inert “clean-agent” fire suppression system which blankets the thermal runaway event and prevents combustion whilst allowing major quantitites of flammables to build up. When finally mixed with air and ignited this creates a major explosion. This is exactly what happened at McMicken Arizona (according to a major forensic report) and Drogenbos, Belgium. The “fire suppression” systems widely advocated help to CAUSE these explosions
• This explosion occurred prior to the arrival of responding fire crews. This was fortuitous since the explosion potential is a significant risk to emergency responders that has caused life-altering injury to firefighters at fire incidents on international BESS sites, such as Arizona and Beijing.
• The presence of residential premises adjacent to the Carnegie Road BESS site raises concerns regarding the ‘off-site potential’ from fire incident risks at BESS sites to the local community.
• Once water was applied, the resulting run-off contained Hydrofluoric Acid (HF) – a highly toxic substance which can dissolve concrete and whose fumes can be fatal to life.
• Further investigation is underway to fully understand the regulatory regime that applies to BESS sites and this incident was brought to the attention of the NFCC (National Fire Chief’s Council) Ops Committee, the Health and Safety Executive (HSE) and Home Office (HO). National Operational Guidance (NOG) were also informed to determine current UKFRS risk assessment standards when responding to similar incidents. An automatic fire suppression system was present and during the course of the incident had activated however, actuation was most likely due to the deflagration, which either activated the alarm or, the pressure activated the break glass media

Our conclusion from these reports is that the Faversham Society remains deeply concerned about the serious thermal runaway risks associated with the BESS at the proposed development at Cleve Hill, particularly on the huge scale proposed by the developers. 

It transpires that even for the Liverpool incident in a relatively small BESS, the fire suppression measures were ineffective, the Fire and Rescue Service were inadequately informed and prepared, and a serious fire and large explosion took place which could have resulted in serious injury or death.

Swale Borough Council will receive the final stage of the planning application for the development at Cleve Hill shortly with details of the battery deployment. The degree of container separation and other measures required to avoid thermal runaway, appropriate arrangements to deliver huge amounts of cooling water, firefighter safety and the environmental impact of thousands of gallons of contaminated water being discharged into the sensitive environment on the marshes, all require careful consideration by Swale. 

This also reinforces our view that the explosion potential and the lack of engineering standards to prevent thermal runaway may put control of ‘battery fires’ beyond the knowledge, experience and capabilities of local Fire and Rescue Services and new approaches to fire suppression and firefighter safety are needed.

When the developers of the Cleve Hill solar power factory submit their final planning application, Swale Borough Council will have just eight weeks to determine it. They will have to take account of all of these issues before granting final planning permission for an installation that could result in serious consequences for the residents of Swale.  This constitutes a huge challenge for Swale Borough Council to insist that risks are minimised for the future safety and well-being of the residents of Swale.

David Melville

April 2022