Renewable Energy Guarantees of Origin (REGO)

Page type: primary-anchored (mirrors REGO Guidance V4.0, March 2026)

Source file: rego.md

What this instrument does

The REGO scheme is the UK's system for certifying that electricity was generated from renewable sources. It is a tracking and transparency mechanism, not a subsidy -- no money flows from the scheme itself. Instead, it creates tradeable certificates (one per MWh of gross renewable generation) that prove provenance.

The scheme is administered by Ofgem under the Electricity (Guarantees of Origin of Electricity Produced from Renewable Energy Sources) Regulations 2003, as amended. It covers both Great Britain and Northern Ireland.

How it works

The certificate

One REGO is issued for every megawatt hour (MWh) of gross renewable electricity generated by an accredited station (Section 1.2). REGOs are issued automatically into the operator's account on the Renewable Electricity Register (RER). They are rounded to the nearest whole MWh, with 0.5 rounding up (6.4).

Critically, REGOs can be traded separately from the electricity (6.21). This means a generator can sell its power to one party and its REGOs to another. This unbundling is the foundation of the green tariff market.

Eligible sources (Section 3.6)

The eligible sources are defined in the Regulations as "renewable non-fossil energy sources": wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas, and biogases. Ofgem has no discretion over this list (3.7).

For hybrid stations (using both renewable and non-renewable fuel), REGOs are issued only on the renewable proportion (3.4). Pumped storage schemes can only claim REGOs on electricity from natural run-off, not pumped water (3.8).

The lifecycle

1. Accreditation (Ch.4): The operator applies via the Register, providing technical evidence. Accreditation date is the later of the station becoming operational or the application date (4.11).

2. Annual declaration (4.17): Every year by 1 April, the operator must sign an Information Declaration to maintain accreditation. Failure prevents REGO issue.

3. Data submission (Ch.5): Monthly or annually (April to March). Minimum claim period is one calendar month (5.9).

4. Issuance (6.1-6.8): Ofgem issues REGOs into the operator's Register account with unique sequential numbers.

5. Transfer (6.20-6.24): REGOs can be transferred between registered holders via the Register.

6. Use: Either redeemed for Fuel Mix Disclosure (automatic), retired for NI FMD, or voluntarily returned for cancellation (RE100/carbon reporting).

7. Expiry: GB REGOs are cancelled 16 months after the month of generation. NI REGOs are cancelled at 19 months.

Primary use: Fuel Mix Disclosure (Chapter 8)

The main purpose of REGOs is to back suppliers' Fuel Mix Disclosure -- the annual statement to customers showing what fuel mix their electricity came from.

• Disclosure period: 1 April to 31 March
• Evidence deadline: Suppliers must hold REGOs in their Register accounts by midday 1 July. At that point, Ofgem automatically "redeems" all valid REGOs in supplier accounts.
• Disclosure to customers: By 1 October annually
• SLC 21 of the electricity supply licence implements the FMD requirement
• Residual mix: Where suppliers cannot evidence their fuel mix, they use the national FMD Data Table published by DESNZ

Green tariffs (8.11)

SLC 21D requires suppliers making environmental claims about their tariffs to hold REGOs for all renewable electricity supplied under a green tariff, with additional requirements for additionality and transparency evidence.

Carbon reporting (8.12-8.13)

REGOs are used in DEFRA/DESNZ Environmental Reporting Guidelines (Scope 2 emissions) and voluntary sustainability disclosures like RE100. For these uses, REGOs must be voluntarily returned for cancellation -- they cannot simply be held.

Post-Brexit position (Chapter 7)

• 1 January 2021: UK REGOs no longer recognised in the EU
• 1 April 2023: EU Guarantees of Origin (GoOs) no longer recognised for GB Fuel Mix Disclosure (formalised by S.I. 2022/1247)
• Northern Ireland exception: EU GoOs remain valid for NI FMD via the Single Electricity Market Operator (SEMO)
• Post-Brexit REGOs can only be voluntarily cancelled for UK energy consumption (6.48)

Enforcement

• Revocation (6.14): Ofgem must revoke REGOs where information was incorrect, fraudulent, or the REGO should not have been issued
• Audit (9.1): Ofgem can request access to plants under Regulation 5; unreasonable refusal can result in Ofgem refusing to issue REGOs
• Criminal liability (4.17): False declarations risk prosecution under Gas Act 1986 s.43 and Electricity Act 1989 s.59
• Withdrawal of accreditation (4.19): If station can no longer generate from eligible renewable sources

Key numbers

Defined terms

See the source file for the full defined terms register.

Cross-references

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Last updated: 2026-04-05