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Major Concerns about Battery Safety

Cleve Hill – Update in preparation for the Battery Safety and Management Plan

We are now expecting the imminent submission to Swale Borough Council by the developers of the Battery Safety and Management Plan (BSMP) for the Cleve Hill Solar Plant. During the 2019 Planning Enquiry for the 350MW Solar Array and 700MWh Battery Energy Storage System (BESS) only sketchy details were provided on the proposed BESS. The BSMS is a crucial document in ensuring the health, safety and well-being of the people of Swale in the face of significant established risks associated with grid-scale BESS.

The Faversham Society were recently invited to a briefing on the upcoming BSMP and the purpose of this note is to assist SBC in its deliberations when the plan is received. This note draws on information provided in that briefing. Our understanding is that the current proposal is substantially different from that presented to the Enquiry. Not least in its reduced size and different battery type and configuration. These significant changes could be enough to argue that this is now a different proposal and, at the very least, require a longer time period for consultation and comment by interested parties.

We believe that the specification and detail of the BESS to maximise its safety is an extremely complex matter depending on recent science and emerging practical experience of incidents around the globe. The Faversham Society therefore strongly urges Swale Borough Council to seek expert advice from a recognised authority on battery safety. Below in the Appendix we suggest such a consultant who besides many assignments around the world has recently provided detailed advice on the Outline Battery Safety and Management Plan for the Sunnica large BESS proposal Enquiry in East Anglia which has recently been through the NSIP process. His evidence is available on the Sunnica Enquiry website.

The Society was active in opposing the BESS on the grounds of the risk of fire or explosion for what then would be the largest such installation in the world. Since that time, on an almost monthly basis, there have been fires and explosions reported for Li-ion batteries throughout the world. The most recent (21/7/23) and very close to home was the two electric car fire at Lydden Hill which besides destroying two racing cars engulfed a service truck and burned down a pavilion. KFRS attended with nine fire engines and a bulk water carrier but were unable to put out the fire. Racing was stopped and presumably, this 105 kWh fire had to be left to burn out. The Cleve Hill battery is 4000 times bigger.

There have been c65 fires and explosions reported in grid-scale BESS across the world to date, primarily in installations that were 2 years old or less. Of these, 38 have been in the last 3 years. Overall, these incidents may have represented up to c6% of global installed capacity, suggesting a significant probability of incidents.

As well as fires, confirmed vapour cloud explosions (VCE) have taken place in Belgium, Arizona and Liverpool The list  below summarises some of the recent grid-scale lithium-ion BESS fires and explosions (VCE) to date,

2012 Arizona, USA

Aug 2016 Wisconsin,USA

Nov 2017,Drogenbos Belgium. VCE. 50 reports of eye and chest irritation downwind of the site.

2018 - 2019 South Korea: around 30 Different BESS caught fire and/or exploded. All completely destroyed. (Reflects very large numbers of BESS in the Country.

April 2019 Arizona, USA. The McMicken BESS explodes badly injuring 2 fire fighters and severely injuring 2 more. All first responders contaminated with hydrogen cyanide. VCE.

March 2020 Nathan Campus of Griffith University, Brisbane. LFP BESS explodes. VCE.

 Sep 2020 Carnegie Road, Merseyside: BESS explodes. VCE.

Dec 2020 Perles-et-Castelet, Ariège France. On-top BESS configuration.

March 2021 SBG-2 OVH cloud data centre in Strasbourg, France.

March 2021 South Korea, North Kyungsan Province, Yeongcheon April 2021 Hongseong,

July 2021 Tesla Megapack BESS,  ignited during testing at the newly registered Victoria Big Battery at Moorabool, Geelong. Fire in one cabinet spread to a second 4MWh.

Invenergy storage facility, LaSalle County, USA

E (July 2021). Märkisch-Oderland, Neuhardenberg airfield, Germany (July 2021)

 4 Sep 2021 Moss Landing, California “world’s biggest battery storage facility” cells go into thermal runaway, still offline.

12 Jan 2022 South Korea, Nam-gu, Ulsan 50 MWh.

17 Jan 2022 South Korea, Gunwi-gun, Gyeongsangbuk-do. VCE

April 2022 Two firefighters were killed and a third injured in the explosion of a 1.5 MW BESS on the roof of the Jimei Home Dahongmen shopping Mall in Beijing. Besides being the first to result in fatalities, the latter incident is notable for two reasons:

(1) the BESS batteries employed were Lithium Ferro Phosphate (LFP) which are widely perceived to be the safest. LFP batteries are planned for the Cleve Hill BESS

(2) the scale of the firefighting operation required 235 fire fighters and 47 fire engines. (See below for comments on water requirements)

Simple probability suggests that the chance of a failure somewhere in a BESS will increase with its size. This is reflected in a statement by a DNV GL employee at a webinar in 2020 that “Over the life of a (industrial) BESS at least one failure will occur. It is unrealistic to eliminate all chance of failure”. DNV GL (now DNV) are acknowledged as world experts in the risk analysis of large lithium-ion battery systems.

According to Professor Paul Christensen of Newcastle University, one of the world’s leading authorities on Li-ion battery safety, ‘’LFP batteries have a worse risk (than the more common NMC type) of Vapour Cloud Explosion simply because the cathode collapse leading to release of free oxygen internally results in delayed ignition. One of the key reactions that occur before thermal run away is the exothermic structural collapse of the cathode which produces oxygen and is believed to initiate ignition: this collapse occurs at a much higher temperature in LFP cells (310°C) [D. Ren et al., ‘Investigating the relationship between internal short circuit and thermal runaway of lithium-ion batteries under thermal abuse condition’, Energy Storage Mat., 34 (2021) 563 – 573]) hence LFP cells are considered “safer” than for example NMC. 

However, this can just delay ignition and hence LFP cells are perceived to have a higher risk of vapour cloud explosion. Further, recent work has shown that the vapour cloud from LFP cells has a lower explosion limit, larger explosion overpressure, higher explosion index and the ignited vent gas has a higher laminar flame speed [H. Wang et al., eTransportation 13 (2022) 100190.]’’  In summary whilst NMC batteries pose a greater fire hazard, the LFP batteries proposed for Cleve Hill carry a greater risk of explosion.

Furthermore the Cleve Hill developers have indicated that 112 factory built modular cabinets supplied by the Chinese company CATL are to be used rather than shipping containers as previously indicated. Again to quote Christensen “Cabinets have a far higher energy density than containers and little free volume: this renders any form of suppression extremely challenging as water (which is still the best of the bad options when it comes to dealing with thermal runaway) will not be able to reach the cells in thermal runaway to prevent thermal propagation.  Recognising this, Tesla recommends that their Megapack cabinets be allowed to burn out.’’ This inevitable practice increases the likelihood of the fire spreading to nearby cabinets and of explosion.

Spurred on by a BESS proposal in her Basingstoke constituency Dame Maria Miller MP has introduced a Bill in Parliament to bring into law a duty for consultation with the Health and Safety Executive, the Environment Agency and Fire Services on all future BESS planning proposals. It is important that the consultation by SBC with KFRS is in the spirit of Dame Maria Miller’s draft Bill, to quote: “The Bill would ensure that industrial lithium-ion battery storage facilities are correctly categorised as hazardous, so that the Environment Agency, the Health and Safety Executive and the fire and rescue services would be statutory consultees when planning applications are considered”

There is currently little legislation or regulation relating to Lithium-ion batteries despite their potential flammability, proclivity to explosion and ability to emit large amounts of highly toxic gases. It is argued however that these properties render them liable to a requirement for Hazardous Substances Consent (HSC) before planning approval. This issue has been raised in the Sunnica Examination and is under current active consideration by the ExA.

Recently two county fire chiefs have (in Hampshire and W Yorks) spoken publicly of the inherent dangers of BESS. The most important and useful development is however that the National Fire Chiefs Council (NFCC) has recently published new National Guidance for FRS on Grid Scale BESS Planning. This work has been led by the NFCC lead officer on Energy Systems, Matt Deadman who is based at KFRS HQ in Maidstone. We were able to discuss the guidance with him in a constructive meeting in June this year.https://www.ukfrs.com › sites › default › files › 2023-04 › Grid Scale Battery Energy Storage System 

This Guidance is a welcome step forward in that it codifies the detailed information requirements for a BSMP in terms of system design, construction, testing, detection, monitoring, suppression systems, site access and unit spacing, distances to site boundaries, water supplies, signage, emergency plans and environmental impacts. It also provides clarity that copious levels of water cooling are the only means of limiting the spread of fire and in our subsequent discussion he made clear that the approach is to let the original fire burn out but to use cooling water to attempt to prevent it spreading to neighbouring units. This practice has however not proved to be universally successful in previous incidents when fire has spread from unit to unit. The guidance lists in detail the large amount of information that the BSMP must contain and provides a useful checklist for SBC Planners and Planning Committee in considering their response.

It appears that that at Cleve Hill the recommended standard minimum spacing of 6m between cabinets with no stacking is to be adopted but this is worryingly lower than the 22m flames recorded in the Arizona battery fire.

As noted above, water is the only extinguishant routinely recommended for lithium-ion battery fires. Large lithium-ion battery fires require very significant quantities of water and can reignite many times after the initial incident. Many of the BESS fires to date have taken days to bring under control and have used and required vast volumes of water to both cool the containers (rather than try to put the fires out directly) and, where necessary, to contain toxic fumes via fogging (see below)

The developers appear to misunderstand this and are relying on the NFCC suggestion of a water-cooling system capable of delivering 'no less than 1,900 litres per minute for at least two hours' This would deliver a total of only 228,000 litres. There is limited data on the measurement of water volumes deployed in previous BESS fires. However, there are at least two well documented incidents which indicate that the requirement is much larger and will be needed over many more hours, if not days:

Moorabol, Victoria, Australia took 900,000 litres over 6 hours for a 4.25MWh fire

Drogenbos, Belgium took 1.4million litres for a 1MWh fire

These are very small BESS compared to the now proposed 448 MWh Cleve Hill BESS and the larger the BESS, the greater the risk of widespread propagation and the greater the risk of multiple simultaneous fires.

We welcome that fire-water run-off is highlighted in the NFCC Guidance, but there should be greater emphasis on the toxicity of very large volumes of fire run-off water and the need for its storage and treatment, linking also to the Environmental Impacts section of the Guidance. We were very concerned to hear from the developers that they propose to collect the highly toxic fire-water and re-use it to augment the fire-fighting.

Finally we note that there has been no mention to date of cyber security threats and we urge that this should be covered in the BSMP. There have been warnings of threats to BESS similar to the DarkSide ransomeware attack on the Colonial Pipeline. Scientists at TUV Rheinland have shown that BESS are vulnerable to hacking and could be used to dump energy onto the grid or turn the BESS into a bomb.


Proposed Consultant who can provide SBC with an independent expert view on the Safety and security of the Cleve Hill BSMS.

CV Professor Paul Christensen

I am an academic electrochemist with over 35 years experience in research. I have over 180 papers in international, peer reviewed journals and an H-index of 53. I am an Editorial Board member of Nature Special Reports. I am Senior Advisor to the National Fire Chiefs Council (NFCC), Special advisor to Tyne and Wear Fire and Rescue Service and I am a Subject Matter Expert to DSTL. I serve on the Crossgovernment Technical Steering Group for EV fire safety, the Department of Business Energy and Industrial Strategy (BEIS) Energy Storage Health and Safety Governance Group, the BEIS Storage Safety - Fire Service Working Group, the British Standards Institute (BSI) PAS 63100 (domestic energy storage systems) Steering Group, the BSI Review Group in the development of the BSI base document for Lithiumion battery cells, modules and packs – Physical storage – Guide and the BSI FSH/2/-/20 – Working Group (lithium-ion battery extinguishers), the Australian Building Codes Board working group on EV safety and the Tyne & Wear FRS and Envision-AESC Gigafactory fire safety working group. I am the recipient of the 2022 Motorola Foundation-funded AFAC Knowledge Event Series lecture tour of Australia, New Zealand and Tasmania (Oct 2022, presenting to first responders, government officials etc). I advised Nissan for 3 years on all aspects of lithium-ion battery safety during the construction and commissioning of the battery plant in Tyne & Wear. I am routinely asked for input and advice by OZEV and the Department for Transport. I have conducted tests and experiments to research thermal runaway at module, pack and vehicle levels. I have assessed a number of LiBESS planning applications in the UK and abroad.

Professor Sir David Melville CBE, BSc, PhD, Hon DSc, FInstP, Sen Mem IEEE(USA)

Vice-Chair, Faversham Society

August 2023

August 21, 2023

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