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REGOs

What are REGOs (Renewable Energy Guarantees of Origin)?

When a UK supplier advertises a 100 per cent renewable electricity tariff, the claim sits on top of a piece of regulatory plumbing called REGOs. Renewable Energy Guarantees of Origin are UK certificates issued by Ofgem for every megawatt-hour of electricity generated from renewable sources. One REGO equals one MWh of renewable generation. Suppliers buy enough REGOs to cover the consumption they sell on green tariffs, retire those REGOs on the Ofgem register, and then claim the matched electricity as renewable. The customer’s actual electricity at the meter is the same blend that flows through every other UK supply. The renewable claim is contractual, not physical. REGOs are how the contractual claim is recorded and made auditable.

REGOs are part of the wider story of how business electricity is procured in the UK, and they shape the green claims you’ll see across most business energy tariffs.

REGOs are the foundation of green electricity claims in the UK. They are also a source of justified scepticism, because the cost of buying a REGO is much lower than the cost of building a new renewable generator. Understanding what REGOs are and what they signal helps you evaluate green tariffs, sustainability claims, and the trade-offs between certificate-backed renewable supply and physical renewable procurement through structures like PPAs.

What a REGO actually is

A REGO is a UK electronic certificate.

• One REGO equals one megawatt-hour (MWh) of electricity generated from renewable sources.
• REGOs are issued by Ofgem to UK-accredited renewable generators.
• The certificate records the generator, the technology, the date of generation, and a unique serial number.
• REGOs are held and traded electronically on the Ofgem Renewables and CHP Register.
• When a REGO is “retired” (matched against electricity sold to a customer), it cannot be used again.

The system creates a one-to-one paper trail between renewable generation and renewable consumption claims, even though the underlying electricity is physically the same blend everywhere.

How REGOs are issued

Ofgem issues one REGO per MWh of accredited renewable generation. Eligible sources include.

• Wind (onshore and offshore).
• Solar PV.
• Hydropower.
• Biomass (where the fuel meets sustainability criteria).
• Tidal and wave (small volumes).
• Energy from waste (the renewable fraction).

Generators register with Ofgem, submit metered output data, and receive REGOs into their Renewables and CHP Register account. Generators can then sell the REGOs separately from the electricity itself, in the open REGO market.

How REGOs are used by suppliers

A supplier offering a green tariff matches its sales to that tariff with retired REGOs.

1. The supplier sells a defined volume of electricity to customers on the green tariff (say, 50 GWh).
2. The supplier buys 50,000 REGOs from the open market or from a generator under direct contract.
3. The supplier retires those REGOs on the Ofgem register against the sales volume.
4. The supplier can then claim the 50 GWh as “100 per cent renewable”.

Annual reconciliation through the Ofgem Fuel Mix Disclosure framework checks that REGO retirements match the renewable volumes claimed.

REGOs and green tariffs

Almost all UK green electricity tariffs are backed by REGOs.

• The customer pays a tariff that the supplier promotes as 100 per cent renewable.
• The supplier matches the consumption with retired REGOs.
• The customer’s Scope 2 emissions (market-based) can be reported as zero on the basis of the REGO-backed supply.
• The physical electricity at the meter is the standard UK grid mix.

The relationship between green tariff and REGO is straightforward. The REGO is the audit trail. The marketing is built on top.

What REGOs cost

REGOs trade in an open market. Prices vary with supply (how much renewable generation is being added to the system) and demand (how many suppliers want to badge their tariffs as green).

• 2018 to 2020. REGO prices were typically 30p to £1 per REGO. Effectively negligible against the cost of the underlying electricity.
• 2021 to 2024. Prices rose sharply with corporate sustainability demand, reaching £6 to £10 per REGO at peak.
• Current range (2026). Prices have stabilised but remain materially higher than pre-2021 levels.

Even at peak, a REGO at £10 per MWh is about 1 p/kWh. The premium that a supplier can charge for a green tariff often exceeds the cost of REGOs by a substantial margin.

Common criticism of REGO-backed claims

REGO-backed renewable claims face three main criticisms.

• No additionality. Buying REGOs from existing generators does not finance new renewable capacity. The generation would have happened anyway.
• Low price signal. When REGO prices are low (as they were before 2021), they create little incentive for new generator investment.
• Disconnection from physical reality. The customer’s actual electricity at the meter is the grid mix, regardless of how many REGOs were retired against the supply.

Defenders point out that REGOs at least create a tradeable signal of renewable preference, give customers a low-cost way of supporting renewables, and underpin the Scope 2 market-based reporting framework that drives corporate climate action.

REGOs vs corporate PPAs

For small and mid-size UK businesses, REGO-backed green tariffs are the practical route to renewable supply. For very large customers with credible sustainability commitments, corporate PPAs deliver more substantive impact and often better long-term pricing.

REGOs and Scope 2 reporting

REGOs are central to market-based Scope 2 reporting under the Greenhouse Gas Protocol.

• A business consuming 1 GWh of electricity on a REGO-backed green tariff can report market-based Scope 2 emissions of zero for that consumption.
• The same business reporting on a location-based basis would still see Scope 2 emissions reflecting the average UK grid intensity (around 207 gCO&sub2;/kWh in 2024).
• SECR, CDP, and most corporate sustainability frameworks expect both metrics to be reported.

The market-based figure recognises the contractual renewable claim. The location-based figure reflects the physical grid.

REGOs and EU GO certificates

The EU operates a similar scheme called Guarantees of Origin (GOs). After Brexit.

• UK REGOs are no longer automatically recognised in the EU.
• EU GOs are no longer automatically recognised in the UK.
• UK suppliers can technically import EU GOs but they are not valid for UK Fuel Mix Disclosure.
• This has created a small premium on UK REGOs relative to EU GOs.

For UK customers buying green tariffs from UK suppliers, the certificates retired are always UK REGOs.

Practical implications for business customers

For UK business customers, REGOs matter in three practical ways.

1. Choosing a green tariff. Almost all UK green tariffs are REGO-backed. The marketing language is similar across suppliers. Real differentiation lies in additionality (does the supplier invest in new renewable capacity) and contract terms, not in whether REGOs are used.
2. Sustainability reporting. A REGO-backed tariff lets you report zero market-based Scope 2 emissions. The location-based figure is unchanged.
3. Decision between tariff and PPA. For larger customers with serious sustainability commitments, evaluating whether REGOs alone are enough (or whether a PPA delivers better outcomes) is a worthwhile exercise at procurement.

Related entries. green tariff, Power Purchase Agreement (PPA), sleeved PPA, Scope 2 emissions, Net Zero, carbon intensity, SECR.

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