The Renewable Energy Directive 2018 ((EU) 2018/2001) requires EU member states to provide a Guarantees of Origin (GOO) scheme to certify production of electricity, heating and cooling from eligible renewable energy. In Great Britain, the equivalent scheme was called the REGO scheme.

The UK left the EU on 31 January 2020 and the REGO scheme has been adopted post-Brexit and amended to ensure it still operates effectively. In Great Britain, REGOs are the main evidence for licensed electricity suppliers to prove the proportion of renewable electricity supplied to their customers for the purposes of the Fuel mix disclosure obligation (FMD obligation). Ofgem, who administers the scheme, sometimes refers to REGOs as Renewable Electricity Guarantees of Origin.

For more information, see Practice note, EU Renewable Energy Directive 2018 (RED2): Renewable energy guarantees of origin (REGOs) and Practice note, Renewable Energy Guarantees of Origin (REGOs): overview.