Renewable Energy Guarantees of Origin

A REGO certificate is issued by Ofgem to the operator of an accredited renewable generation station, one certificate per megawatt-hour of renewable electricity generated. REGOs are the UK implementation of the European Guarantees of Origin scheme and are the auditable evidence behind any UK supplier's claim that a tariff is "100% renewable".

There are two structurally different ways suppliers source REGOs:

• Bundled: REGOs procured directly from a generator alongside the underlying physical electricity supply, often via a Power Purchase Agreement (PPA). This produces the strongest audit trail and is the structure that withstands ESG scrutiny.
• Unbundled: REGOs purchased separately from the physical electricity, often at very low prices on the secondary market. The supplier matches a customer's consumption to the certificates on paper but the underlying physical electricity may be from a mixed grid or fossil source.

Both approaches are technically compliant with the rules of the REGO scheme, but the difference matters for any customer making public renewable claims under SECR, TCFD, ISSB-aligned reporting or supply-chain ESG demands. We recommend bundled REGO-backed supply or PPA-linked procurement for customers whose renewable claim is part of public-facing sustainability reporting; unbundled REGOs are usually only appropriate where the cost differential is significant and the audit trail does not need to withstand external assurance.