The Renewable Energy Guarantees of Origin scheme derives from EU law and is intended to provide transparency to consumers about the proportion of electricity that suppliers source from renewable generation. The vast majority of REGOs in the UK are issued to projects that are also in receipt of public subsidy, so it is difficult to isolate the exact impact REGO value will have had on the business cases for individual projects or on renewables deployment overall. The Electricity (Fuel Mix Disclosure) Regulations 2005 requires electricity suppliers to declare the fuel mix of their supply. This lays out the method suppliers must use to calculate the fuel mix that they publish on their website and use in promotional materials. Companies include electricity covered by REGOs as renewable electricity in their Fuel Mix Disclosure tables. Ofgem, as the independent regulator, hold a supply licence condition (21D) which requires a supplier who attaches an Environmental Claim to a tariff to meet requirements on additionality, transparency and evidence of supply. The Government is continuing to work with Ofgem to ensure that regulation of the retail market (including the supply licence) remains fit for purpose through the energy transition as consumers play an increasingly important role in achieving net zero.