Battery energy storage systems BESS

Battery Energy Storage Systems (BESS) "use batteries, for example lithium-ion batteries, to store electricity at times when supply is higher than demand. They can then later release electricity when it is needed. BESSs are therefore important for the replacement of fossil fuels with renewable energy."

"The (UK) government has a legally binding target to reduce the UK’s greenhouse gas emissions by 100% by 2050, compared with 1990 levels. This is known as the ‘net zero target’. To meet this target, the government has set the aim of achieving “clean power by 2030”. This means “being on track to achieving at least 95% of low carbon generation by 2030”. Renewables, such as wind and solar power, rely on the weather to generate electricity. This means that they cannot adjust to demand from consumers as easily as fossil fuels and nuclear power can. Therefore a decarbonised power system will need to be supported by technologies that can respond to fluctuations in supply and demand, including energy storage. The government’s Clean Power Action Plan stated that it expected 23–27 GW of battery storage to be needed by 2030 to support clean power, up from 4.5 GW in 2024." Research Briefing: Battery energy storage systems - 23 June 2025 By Georgina Hutton, Iona Stewart

"BESS use lithium-ion batteries. When managed correctly these batteries can be operated safely and the likelihood of problems are low. However, when faults do occur, these batteries can pose a significant fire risk due to thermal runaway. Thermal runaway occurs when a battery generates heat faster than it can dissipate it. This can result in the rapid production of large volumes of toxic and explosive vapours and lead to explosion and fire."

"When lithium-ion batteries burn they produce oxygen, the chemical reaction in the battery continues to produce heat, and various fuels are also present. This means that these fires are very difficult to extinguish as water cannot access the battery cells meaning thermal propagation from cell to cell continues. Furthermore, if a fire occurs, it may reignite even in the absence of oxygen, making these fires particularly dangerous for both the public and for firefighters."

"Though rare, BESS fires are challenging to extinguish and can continue to burn from several hours to several days. A fire in Liverpool, in 2020, lasted 3 days. Smoke plumes from fires can also harm air quality. However, trying to extinguish fires using water can result in large volumes of contaminated fire-water run-off which can have a long-term impact on the environment. As a result, the prevailing view when it comes to firefighting tactics is to adopt a ‘controlled burn’ to minimise runoff whilst protecting the surrounding area from flame and heat impingement. This decision is often taken based on the battery chemistry and site specific plan, and taken in consultation with the Environment Agency."

"The UK Battery Strategy sets out that the Faraday Institution and Bloomberg NEF models estimate that BESS could provide 10-20GW of capacity to the UK grid by 2030, and 30-35GW by 2050, representing the largest installed capacity compared to other storage technologies. In their models of total demand, the Faraday Institution and Bloomberg NEF estimate around 5-10GWh demand for grid storage by 2030."