Question to the Department for Energy Security & Net Zero:

To ask the Secretary of State for Energy Security and Net Zero, with reference to the Answer of 24th April 2026 to Question 127931, what measures the National Energy System Operator uses regarding renewable intermittency when advising on required Capacity Market volumes.

For the purposes of the Capacity Market and advising on the capacity required to ensure security of electricity supply in Great Britain, the National Energy System Operator (NESO) considers the de-rated capacity of technologies, the portion of capacity considered reliably available to reflect their expected contribution to security of electricity supply during times of system stress.

The intermittency risks associated with renewable technologies is reflected in the de-rating factor applied.  These de-rating factors are determined by the NESO and are detailed in their annual Electricity Capacity Report.

NESO are able to help with questions on the methodologies used in the ECR.