Summary
Details
- The United Kingdom
The obligation that matters most commercially is Fuel Mix Disclosure.
Licensed electricity suppliers must disclose their annual fuel mix to customers.
Where renewable electricity is claimed within the applicable FMD system, REGOs provide the relevant evidence of renewable origin.
Renewable electricity generators are not generally required to obtain REGOs simply because they generate renewable electricity.
Participation becomes relevant where the generator wants certificates to represent and potentially transfer the renewable attributes of its output.
Deep dive
- What’s Required
- 1. Obtain REGO accreditation
- 2. Generate electricity from an eligible renewable source
- 3. Submit generation data
- 4. Receive one REGO per MWh
- 5. Maintain accurate generation evidence
- 6. Transfer REGOs through the register
- 7. Use REGOs for Fuel Mix Disclosure
- 8. Avoid double claiming
- 9. Distinguish REGO from physical renewable electricity
- 10. Maintain appropriate claims
- Fuel Mix Disclosure
- Important Deadlines
- Current Status
- Penalties for Non-Compliance
- Examples of Known Violations / Failure Modes
- Resources
📩 Stay ahead of climate regulation and reporting shifts
Regulatory updates, reporting standards, and new climate software — distilled into one concise weekly brief for decision-makers.
Thanks for signing up. Please check your inbox to confirm your subscription.
Practical updates. Once per week.
What’s Required
1. Obtain REGO accreditation
Generating stations that want REGOs must apply through Ofgem's Renewable Electricity Register (RER).
Eligible generating stations in Great Britain and Northern Ireland can apply.
Generators participating in other schemes such as the Renewables Obligation or Feed-in Tariff may be able to use a combined application process.
2. Generate electricity from an eligible renewable source
REGOs are issued only for qualifying renewable electricity.
Eligible renewable sources can include technologies such as:
Wind.
Solar.
Hydropower.
Geothermal.
Tidal and wave energy.
Certain biomass and biogas generation.
Fuelled generating stations may need to provide additional evidence to determine what proportion of output qualifies as renewable.
3. Submit generation data
Accredited generating stations must submit appropriate generation data to Ofgem.
The REGO reporting year runs from:
April 1 to March 31.
Information submitted must allow Ofgem to determine the quantity of eligible renewable electricity generated.
4. Receive one REGO per MWh
For eligible generation:
1 REGO = 1 MWh of renewable electricity.
This certificate represents the renewable origin attribute of that electricity rather than the physical electricity itself.
5. Maintain accurate generation evidence
Generators need records capable of supporting their REGO claims.
Depending on technology, evidence may cover:
Metered generation.
Fuel use.
Renewable fuel proportions.
Station configuration.
Commissioning information.
Generation periods.
Incorrect or unsupported information can affect certificate issuance.
6. Transfer REGOs through the register
REGOs can be transferred between account holders through the Renewable Electricity Register.
This allows certificates to move separately from the physical electricity and enables suppliers or other market participants to acquire renewable attributes for disclosure purposes.
7. Use REGOs for Fuel Mix Disclosure
The principal regulatory use of REGOs is Fuel Mix Disclosure.
Licensed electricity suppliers in Great Britain must disclose annually the fuel mix of electricity supplied to customers.
REGOs are used to demonstrate the proportion attributed to renewable electricity.
8. Avoid double claiming
The same renewable attribute should not be used more than once.
REGO certificates therefore need to be appropriately held, redeemed or retired according to the intended use.
Ofgem's March 2026 guidance added further clarification on the retirement of REGOs, reflecting uses beyond statutory FMD, including voluntary renewable electricity claims.
9. Distinguish REGO from physical renewable electricity
A REGO provides evidence of the generation attribute.
It does not demonstrate that a particular physical electron delivered to a customer originated from a specific renewable generator.
This distinction matters when companies make environmental marketing or Scope 2 electricity claims.
10. Maintain appropriate claims
Ofgem guidance recognizes that REGOs can also be used for purposes including:
Sustainability disclosures.
RE100-related renewable electricity evidence.
Carbon accounting.
Voluntary renewable electricity claims.
Organizations should therefore ensure claims accurately reflect what the certificate demonstrates.
Fuel Mix Disclosure
Fuel Mix Disclosure requires licensed electricity suppliers to report the proportion of electricity supplied from:
Coal.
Natural gas.
Nuclear.
Renewable sources.
Other sources.
The disclosure is made annually to existing and prospective customers.
REGOs provide the principal evidence supporting renewable electricity within that calculation.
Important Deadlines
October 3, 2003: The original REGO Regulations were made.
October 27, 2003: The 2003 Regulations came into force.
January 1, 2021: EU Member States stopped recognizing UK REGOs following Brexit.
April 1, 2023 disclosure period onward: EU Guarantees of Origin are no longer recognized for GB Fuel Mix Disclosure, FIT annual levelization or Contracts for Difference purposes.
May 23, 2025: Ofgem published updated REGO guidance.
March 2026: Ofgem issued version 4.0 of its REGO guidance, including new clarification on retiring REGOs.
April 1 to March 31 each year: REGO generation reporting period.
Annual: Licensed electricity suppliers must meet Fuel Mix Disclosure requirements.
Current Status
Active.
As of November 2026, REGO remains the UK's principal renewable electricity origin certificate system.
Ofgem continues to administer REGOs for generating stations in Great Britain on behalf of the Department for Energy Security and Net Zero and in Northern Ireland on behalf of the Northern Ireland Utility Regulator.
Ofgem also published dedicated guidance in May 2026 for the 2026 Great Britain Fuel Mix Disclosure process.
Relationship with EU Guarantees of Origin
Brexit created an important separation between the UK and EU certificate systems.
Since January 1, 2021, EU Member States no longer recognize UK REGOs.
The UK initially continued recognizing EU Guarantees of Origin, but this changed subsequently. From the disclosure period beginning April 1, 2023, EU GoOs are no longer recognized for:
Great Britain Fuel Mix Disclosure.
FIT annual levelization.
Contracts for Difference.
Penalties for Non-Compliance
There is no standalone financial penalty merely for a renewable generator choosing not to participate in REGO.
However, licensed electricity suppliers have regulatory Fuel Mix Disclosure obligations.
Where a supplier breaches licence or disclosure requirements, Ofgem can use its broader regulatory enforcement powers.
Potential consequences can include:
Compliance directions.
Enforcement action.
Financial penalties under applicable energy regulation.
Correction of inaccurate disclosures.
Reputational consequences from incorrect renewable electricity claims.
Ofgem can also refuse to issue or recognize certificates where scheme requirements have not been met.
Examples of Known Violations / Failure Modes
Typical compliance and integrity risks include:
Incorrect generation data.
Claiming more renewable output than supported by metering.
Incorrectly calculating renewable fractions at fuelled stations.
Using certificates for the wrong disclosure period.
Double claiming renewable attributes.
Failing to transfer certificates correctly.
Incorrect Fuel Mix Disclosure.
Inadequate evidence supporting renewable generation.
Claiming physical renewable electricity delivery solely on the basis of certificates.
Failing to retire certificates appropriately for voluntary claims.
Attempting to use EU GoOs for GB FMD after they ceased to be recognized.
Attempting to use UK REGOs for EU disclosure where the EU no longer recognizes them.
Resources
Cut through the green tape
We don't push agendas. At Net Zero Compare, we cut through the hype and fear to deliver the straightforward facts you need for making informed decisions on green products and services. Whether motivated by compliance, customer demands, or a real passion for the environment, you’re welcome here. We provide reliable information. Why you seek it is not our concern.