The world-record breaking Cleve Hill Battery Energy Storage System (BESS) is being planned for a location just a few miles east of the site of the Great Gunpowder Explosion of 1916. There is a real danger of history repeating itself due to thermal runaway in Li-ion batteries, a technology for which the Health and Safety Executive has developed no standards or regulations. We have just coauthored and published a comprehensive report on the ‘Safety of Grid-Scale Lithium-ion Battery Energy Storage Systems' which lays out the science and analyses these dangers.
The report draws attention to the many Li-ion BESS fires around the world including a recent one in Liverpool in September 2020 which is still the subject of investigation. A highlighted issue is the difficulty of extinguishing these ‘fires’ since they do not require oxygen to burn and can only be dealt with by deploying prodigious amounts of cooling water. The reason is that they can and do continue to reignite for days whenever local temperatures in the battery stack rise above 150C and there is still energy stored.
25,000 gallons of water were required to contain the Tesla car “fire” in Texas April, 2020. The Cleve Hill BESS is 7,000 times larger than this car battery. 175 million gallons, or the equivalent of about 318 Olympic-size swimming pools, might therefore be needed to manage a major thermal runaway event at Cleve Hill. The proposed solar power station infrastructure at Cleve Hill couldn’t possibly contain that amount of contaminated water, so it would inevitably flow out into the drainage ditches that crisscross the site and, from there, out into the Swale SSSI and the Thames Estuary beyond. In terms of toxicity, levels as low as 5ppm are enough to cause eye damage in humans, so the environmental consequences of such contamination would be catastrophic.
With many more BESS being built throughout the world Li-ion fires and explosions are regularly in the news. Since our paper was published there have already been two major and damaging incidents reported:
On 16th April this year an explosion occurred as firefighters were dealing with a fire in a 25MWh Lithium-ion battery associated with a 1.4MW rooftop solar array at an electric vehicle charging station in the Chinese capital. Two firefighters were killed, and 235 firefighters had to be deployed with 47 fire trucks from15 fire stations.
The proposed BESS at Cleve Hill is 700MWh – 28 times larger than Beijing. If we scale up the Beijing experience to a potential disaster at Cleve Hill it would require 6,580 firefighters, of whom 56 could die, and a fleet of 1,316 fire trucks. Clearly, these figures are absurd, especially since Kent Fire and Rescue Service (KFRS) only has a total of 75 fire engines spread across the whole county. They simply serve to illustrate that the fire would be impossible to extinguish and would have to be left to burn out with consequential pollution and risk to health. The only option must be to introduce prevention measures to make the probability of thermal runaway vanishingly small along with appropriate safety protocols and protection for firefighters.
On the 29th June this year a fire occurred in a warehouse in Morris, Ill. storing 80-100 tons of Lithium-ion batteries. Despite desperate attempts to extinguish the blaze using 28 tons of cement the fire continued for three days and 3,000 people were forcibly evacuated in a 10 mile radius that included 1,000 homes. A week later the evacuation was still in force due to the persistence of the clouds of toxic fumes.
This volume of batteries equates to approximately a 15 MWh BESS. Cleve Hill is planned to be 47 times larger. A 10 mile radius evacuation around Cleve Hill would embrace the whole population of Faversham, Sittingbourne and Canterbury District.
The Faversham Society remains deeply concerned about the serious thermal runaway risks associated with the proposed development at Cleve Hill, particularly on the scale proposed by the developers. 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.
As the paper makes clear "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. This has already proved to be the case for incidents in the USA and lives have been lost.
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. They do have the power to ensure that risks are minimised. For the future safety and wellbeing of the residents of Swale it is not a challenge which can be ducked.
Professor Sir David Melville CBE, FInstP
Professor of Physics
Vice Chair, Faversham Society
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