Question to the Department for Business, Energy and Industrial Strategy:

To ask the Secretary of State for Business, Energy and Industrial Strategy, what estimate his Department has made of the capital cost of seasonal electricity storage capacity.

There are a range of technologies that could provide longer duration storage, including seasonal electricity storage. BEIS has published technical data and cost projections for electricity storage technologies that could be commercially deployed in the future, available here: https://www.gov.uk/government/publications/storage-cost-and-technical-assumptions-for-electricity-storage-technologies. This report shows that the capital costs of the different technologies vary widely.