Battery energy storage systems (BESS)

Battery energy storage systems (BESSs) 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 government set 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 “a fully decarbonised […] power system by 2035”.

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, the government has said 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 expects demand for grid energy storage to rise to 10 gigawatt hours (GWh) by 2030 and 20 GWh by 2035.

What permissions do BESSs need?

Installing a grid-scale BESS requires planning consent. Planning is a devolved matter, and decision-making rules differ across the UK.

In England and Wales, decisions on BESSs (regardless of their capacity) are made by local planning authorities. In Scotland and Northern Ireland, BESSs require consent from either ministers or the planning authority depending on their storage capacity.

Depending on its capacity, a BESS may also require a generating licence to operate. Generating licences are issued by Ofgem in Great Britain or by the Utility Regulator in Northern Ireland.

Concerns about the safety of BESSs

Although safety incidents for BESSs are rare, a common concern about BESSs is the potential fire risk of lithium-ion batteries (PDF). Lithium-ion batteries can catch fire because of a process called “thermal runaway”. It can occur, for example, if part of a battery is damaged.

Understanding of thermal runaway has improved in recent years, leading to more flame-resistant batteries. BESS sites can be also designed with safety features, such as fire suppression systems, to ensure their safety.

There is no reliable, publicly accessible record of the number of BESS fires that have occurred in the UK or elsewhere. There has been one documented incident of a BESS fire in the UK, when a battery system containers at a BESS site in Liverpool caught fire in September 2020 (PDF).

How is the safety of BESSs regulated?

There are no laws that govern the safety of BESSs specifically. However, individual batteries may have to adhere to product safety regulations, and grid-scale facilities may also have to comply with fire safety requirements and health and safety laws.

In response to concerns about the safety of BESSs, the government said BESSs were covered by “a robust regulatory framework”. It published guidance in August 2023 which encourages developers and local planning authorities in England to consult their local fire and rescue service in preparing and deciding on planning applications for BESSs.

The government is also undertaking a review of batteries regulations and, as part of this review, is considering “safety risks associated with all batteries”.

Barriers to the development of BESSs

The Commons Business and Trade Select Committee has raised concerns that the UK has “insufficient domestic manufacturing capacity” for batteries, and the Commons Foreign Affairs Select Committee has raised concerns that “the UK is almost completely dependent on imports for critical minerals”, such as lithium, that are used in batteries.

The government set out how it intends to secure the UK’s battery supply chain and improve the resilience of the UK’s critical minerals supply in its UK battery strategy (November 2023) and critical minerals strategy (July 2022).  

Barriers to the development of BESSs and other energy storage systems also include high upfront capital costs, uncertain revenue streams and delays to grid connections. In response to these concerns, the government published its  action plan to accelerate grid connections in November 2023.

The government also recently consulted on proposals to enable investment in long duration storage.