This Practice Note looks at the Capacity Market (CM) under the electricity market reform (EMR) programme. It provides an introduction to the purpose and legal basis of the Capacity Market, explains what types of electrical capacity Capacity Market support is available to, how Capacity Market support is won, and the form that Capacity Market support takes. It also provides an overview of the key parties involved in the Capacity Market, the Capacity Market auctions that have taken place to date and the key Capacity Market legislation, rules, guidance and consultation documents. It include analysis of the annulment and subsequent re-confirmation of State aid clearance for the Capacity Market mechanism, following the General Court’s 15 November 2018 judgment in respect of Case T-793/14 Tempus Energy Ltd and Tempus Energy Technology Ltd v Commission.