Energy Storage Capacity vs. Renewable Penetration: A Study for the UK

Abstract This paper explores how the requirement for energy storage capacity will grow as the penetration of renewables increases. The UK’s electric grid is used as a case study. The paper aims to provide insight on what is the most economical solution to decarbonize the electric supply. A two-dimensional study varying the penetrations of wind and solar PV is carried out to identify the most appropriate generation mix for the country. The study is based on 9 years of demand and generation data with a 1hr resolution. It discusses the risk of underestimating the storage capacity needed, by failing to capture the inter-annual variability of renewables and analyzes the economic trade-off between over-generation (curtailment) and storage capacity. It also aims to determine the percentage of over-generation that minimizes the total cost of electricity. Results suggest that the UK could need a storage capacity of approximately 43TWh to decarbonize its electricity supply. This figure considers a generation mix of 84% wind + 16% solar PV, a roundtrip storage efficiency of 70%, and 15% of curtailment. Based on current costs of bulk energy storage technologies, this storage capacity translates into an investment of ∼£165.3 billion or approximately 7% of the country’s GDP.