Addressing electricity transmission network congestions using battery energy storage systems – a case study of great Britain

The UK has set an objective of achieving a clean power by 2030, with a specific commitment to deploying 50 GW of offshore wind capacity within the same timeframe. However, the current transmission network lacks the capacity to accommodate these ambitious goals, highlighting the urgent need for substantial reinforcement to support the increased generation and demand at the transmission level. This paper investigates the integration of Battery Energy Storage Systems (BESS) as a non-networked solution, offering a timely and less expensive alternative to traditional network upgrades to address transmission bottlenecks in Great Britain (GB). Using DIgSILENT PowerFactory 2024, the study models the GB transmission network for 2024 and 2030, focusing on peak winter and minimum summer demand scenarios. Contingency analysis and hosting capacity assessments have identified critical bottlenecks which pose significant risks to system reliability during peak periods. This study focuses on South Wales, examining how flow decomposition techniques can be applied to identify locations for BESS deployment to address these bottlenecks. The findings demonstrate that strategically placed BESS can effectively alleviate transmission system bottlenecks. For the specific case analysed, the equivalent annualised cost of the non-networked solution is significantly lower, ranging from 38 % to 63 % of the cost of line reinforcement. Additionally, this approach offers the advantages of faster implementation and enhanced facilitation of renewable energy integration, underscoring its potential as an efficient solution for addressing transmission network bottlenecks.