Can battery deployment avoid network reinforcement in an unbundled electricity system? A Great Britain case study

By 2026, significant quantities of batteries, over 7 GW, have been deployed on Great Britain (GB)’s electricity networks, and over 200 GW of battery projects have been proposed. Batteries are independently owned, and can engage in a number of activities, including wholesale trades. Using three case study periods, this study simulates the behaviour of a short-duration battery, engaged in wholesale trades, to explore whether it reduces peak flows across GB’s electrical networks, and thus may reduce or defer the need for network reinforcement. The approach is novel in applying an agent model representing the actions of a rational battery operator within real-world case study areas. The effect of battery activity on distribution network congestion is investigated at three locations in Scotland, including demand- and wind generation-dominated networks. This study found that simulated batteries’ trades reduced peak network flows, at times, but at other times, the battery activity exacerbated both maximum import and maximum export flows. The effect of battery trading on transmission network congestion was also investigated, across the whole of Scotland. Scotland has over 14 GW of wind generation capacity, commonly curtailed at times of high wind because of transmission constraints. This work found that batteries would both import and export energy during times of high wind generation, both relieving and adding to transmission congestion during such times. In short, this work has found that GB’s single price area encourages battery actions which sometimes fit poorly with conditions on a local, regional and even national scale. Network owners should thus consider the possibility that batteries and other flexible assets may not always reduce, but in fact may add to maximum network flows and reinforcement needs.