Powering the Future

The Role and Development of Battery Energy Storage Systems (BESS) in Achieving Net-Zero Goals

As the UK advances towards its goal of achieving net-zero by 2050, the widespread adoption of renewable energy sources is essential. In 2024, 29% of energy generation comes from wind power, while an additional 6% is generated from solar energy. The Labour Party has pledged to double onshore wind capacity, triple solar energy, and quadruple offshore wind generation, currently the highest in the world, by 2030. While this policy is necessary, it must be noted that solar and wind power are inherently intermittent, with energy output varying significantly with weather conditions and time of year.  Wind turbines generate energy for approximately 80% of the year, while a solar panel in an optimal location can receive 4 to 5 hours of full solar output during the summer and only about an hour in the winter, assuming perfect weather conditions.

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The challenges of renewable energy are twofold. Firstly, energy generation is inconsistent, leading to an unreliable supply of renewable energy. Secondly, energy is often wasted during peak production times. Electricity generated from renewable sources is fed directly into the national grid, regardless of demand, resulting in excess energy being wasted due to insufficient storage capacity. Incredibly, wind farm owners have been paid to shut down energy generation during peak production periods due to an excess of supply; this process is known as curtailment. Curtailment payments have already cost 575 million GBP in 2024. Additionally, a backup energy source is necessary for times when renewable sources are not generating energy, a service typically provided by coal plants.

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If the new government maintains its ambitious renewable energy infrastructure goals, sufficient energy storage systems will be crucial to address intermittency and ensure a reliable supply of renewable energy. Battery Energy Storage Systems (BESS) offer a solution by storing excess energy during peak production times and releasing it back onto the grid when demand exceeds supply. These systems are pivotal for achieving net-zero targets and reducing reliance on fossil fuels.

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A BESS contains thousands of lithium-ion batteries that convert electrical energy into chemical energy during the charging phase. When electricity is generated by solar and wind farms, any excess energy drives an electrochemical reaction inside the battery. This releases lithium ions at the cathode, which transfer through the electrolyte to the anode. When there is an energy shortage in the grid, the reverse reaction occurs: lithium ions flow back to the cathode, converting chemical energy into electrical energy as electrons flow to complete the circuit, releasing the stored energy onto the grid to meet the shortage.

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A BESS unit must have a high cycle life (the number of lifetime charges), a high energy density, and a fast discharge rate. Currently, lithium-ion batteries are the preferred cell technology as they possess many of these characteristics. However, the technology remains expensive, with BESS installations requiring substantial up-front costs with no guarantee of immediate returns. Thus, government legislation is crucial to attract investment and ensure reliable revenue streams.

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The UK currently has the second-largest BESS network in the world, with an installed capacity of 4.4 GW, second only to the US which has 15.5 GW. To meet net-zero targets, an estimated 29 GW of capacity is required, warranting significant investment to keep pace with solar and wind farm development. The previous Conservative government endeavoured to ease planning restrictions, with Kwasi Kwarteng, Minister for Energy and Clean Growth at the time, acknowledging that “the key to capturing the full value of renewables is in ensuring homes and business can still be powered by green energy even when the sun is not shining, or the wind has stopped blowing.”

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Subsequent legislation involved removing planning ‘red tape’ for projects over 50 MW, reducing delivery times by over 18 months. The impact of this policy has been remarkable, with the capacity of pipeline projects surging from 50.3 GW to 95.6 GW in a single year. Additionally, it has attracted substantial private sector investment, as specialist energy storage funds are enticed by reduced infrastructure costs and opportunities for energy trading profits.

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However, the UK currently relies heavily on the import of lithium-ion battery technology from China, with minimal domestic manufacturing capabilities. Since lithium-ion batteries are an essential component of BESS, the UK must secure a reliable supply of cheap cells to deliver cost-effective energy storage solutions. The UK’s Department for Business and Trade aims to address this issue, becoming globally competitive in the battery supply chain by 2030. An investment of 2 billion GBP has been pledged to support research and development in battery technology, with an additional 11 million GBP available for the winners of the Faraday Battery Challenge, encouraging the design of innovative battery technologies.

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Concerns have been raised regarding the safety of BESS, particularly surrounding the risk of thermal runaway caused by defects that can lead to battery fires. Lithium-ion fires are particularly dangerous because they generate oxygen while burning, rendering traditional extinguishing techniques futile. Additionally, BESS installations often use ‘second-life’ batteries that have previously been used in EVs, increasing the concerns associated with the safety of the technology. However, only one BESS fire has ever been reported in the UK, with newer system designs incorporating smaller battery racks, which limit damage from thermal runaway and isolate any short circuits.

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The Labour government’s ambitious renewable energy infrastructure commitments must be coupled with the implementation of BESS if the UK is to achieve its net-zero goals and address the challenges of intermittency. Saving the energy system an estimated 50 billion GBP by 2050, BESS can eliminate costly curtailment payments and reduce reliance on coal plants for backup power. Labour should take note of the effective BESS policies introduced by the Conservative government, which have positioned the UK as an early global leader in energy storage. Prioritising investment in domestic battery technology will help the UK ensure self-reliance and reduce the cost of BESS infrastructure. This approach will enable a reliable supply of affordable renewable energy and support a low-carbon, net-zero future.