REGO certificates: what they are and how they work in the UK
A REGO certificate, short for Renewable Energy Guarantee of Origin, is the certificate Ofgem issues to show that one megawatt-hour of electricity was generated from a renewable source. REGO certificates are how UK electricity suppliers evidence the renewable share of the power they sell, and how a business on a green tariff or a PPA can check the claim behind it.
What is a REGO certificate?
A REGO (Renewable Energy Guarantee of Origin) is an electronic certificate that Ofgem issues for each megawatt-hour of eligible renewable electricity an accredited generating station produces. Suppliers use REGOs to back the renewable share they declare in their annual fuel mix disclosure. Because a REGO can be transferred separately from the electricity, it proves where a megawatt-hour came from, not that any particular customer used it.
Key takeaways
- One REGO represents one megawatt-hour of renewable output, issued by Ofgem to accredited generating stations in Great Britain and Northern Ireland.
- Their main job is fuel mix disclosure: suppliers hold REGOs to evidence how much of the electricity they supplied came from renewable sources.
- REGOs can be traded separately from the power, so a certificate shows origin, not that your purchase paid for any new generation.
- A GB REGO is cancelled 16 months after the month of generation if nobody has used it.
- Under a PPA the certificates go where the contract says. On-site output earns REGOs too, so an on-site deal needs a certificate clause if you want to call the power renewable.
What a REGO certificate is
A REGO is the UK's certificate of renewable origin for electricity. Ofgem issues one REGO for each megawatt-hour of eligible renewable output from an accredited generating station, and each certificate records the station, the technology and the period of generation it relates to. REGOs exist only electronically, on Ofgem's Renewable Electricity Register, where they are issued, transferred between account holders and finally used or cancelled. Ofgem issues them to eligible generators free of charge.
The scheme rests on the Electricity (Guarantees of Origin of Electricity Produced from Renewable Energy Sources) Regulations 2003, which gave effect in Great Britain to the EU's guarantee of origin rules. That is why the certificate's full name is a Renewable Energy Guarantee of Origin, and why EU legislation calls the equivalent certificate a Guarantee of Origin, or GoO. Ofgem runs the scheme for Great Britain and, since February 2009, for Northern Ireland on the Northern Ireland regulator's behalf.
Sources: Ofgem — Renewable Energy Guarantees of Origin; Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026). Verified 27 Sep 2026.
Who issues REGOs and who can get them
Ofgem issues REGOs, and only to the operator of an accredited generating station or an agent the operator appoints. Renewable generators of any size can apply; there is no minimum capacity. Accreditation is a one-off application through the Register. After that the operator submits output data, monthly, annually or for several months at once, and Ofgem issues certificates against it.
The eligible sources are set in the regulations: wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases. A station that runs purely on an eligible source receives REGOs on its gross generation. Ofgem's guidance is explicit that a station which uses some or all of its output on site is still eligible. A rooftop solar array can therefore earn REGOs on every megawatt-hour it produces, including the units the building consumes and never exports.
That rule matters for anyone on an on-site PPA, and we come back to it below.
How suppliers use REGOs: fuel mix disclosure
Every licensed electricity supplier in Great Britain has to tell its customers what mix of fuels generated the electricity it supplied, under the Electricity (Fuel Mix Disclosure) Regulations 2005. REGOs are the evidence for the renewable part of that mix.
| Step | What happens | When |
|---|---|---|
| Disclosure period | The year the fuel mix covers | 1 April to 31 March |
| Evidence deadline | REGOs for generation in that period must sit in the supplier's Register account; Ofgem then redeems them automatically | Midday 1 July after the period ends |
| Disclosure to customers | The supplier publishes its fuel mix | By 1 October each year |
| Expiry | A GB REGO nobody has used is cancelled | 16 months after the month of generation |
So when a supplier sells a "100% renewable" tariff, what stands behind the claim is a stock of REGOs equal to the electricity those customers used, redeemed against that year's disclosure.
Sources: Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) (chapters 5, 6 and 8); The Electricity (Fuel Mix Disclosure) Regulations 2005. Verified 27 Sep 2026.
What a REGO proves, and what it does not
Ofgem's guidance states plainly that REGOs can be transferred separately from the renewable electricity. A supplier can buy its power from one place and its certificates from another. That is how the scheme is designed, and it explains both what a REGO is good for and where its limits lie.
| A REGO does prove | A REGO does not prove |
|---|---|
| That a specific megawatt-hour was generated from a renewable source at a named station | That the electricity reached your meter; certificates and power travel separately |
| Which technology, station and period of generation it came from | That your purchase caused any new generation to be built, the property usually called additionality |
| Who holds it at any moment, because the Register is conclusive proof of the holder | That the power was generated at the same time you used it; matching runs over a year, not hour by hour |
None of that makes a REGO worthless. It makes it a certificate of origin rather than a guarantee of impact. If additionality matters to your board or your customers, the stronger route is a contract with a specific, new generator, which is where a PPA comes in.
REGOs and your business's renewable electricity claim
Beyond fuel mix disclosure, Ofgem recognises that REGOs are used in voluntary sustainability disclosure and carbon reporting. To use them that way, the holder voluntarily returns them for cancellation on the Register, naming the reason (RE100, carbon reporting or another stated purpose). Ofgem then issues a cancellation letter that verifies the renewable electricity was consumed by the listed beneficiary. That letter is the paper trail an auditor will ask for. Cancellation has to happen within the certificates' 16-month life, and only for UK electricity that has already been consumed.
Ofgem's guidance also states that REGOs can be used to evidence a company's Scope 2 emissions under the government's Environmental Reporting Guidelines. Those guidelines make market-based reporting optional under Streamlined Energy and Carbon Reporting, and recommend showing it alongside a location-based figure.
Under the GHG Protocol's Scope 2 Guidance, the market-based method derives emission factors from contractual instruments. These include supply contracts bundled with certificates, unbundled certificates, and PPAs that convey them. In Great Britain the certificate in question is the REGO. The location-based method ignores contracts and uses the average emissions of the grid, which is why a green tariff changes one Scope 2 figure and not the other. Our guide to Scope 2 reporting with a PPA covers both methods.
Sources: Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) (6.33–6.48); HM Government — Environmental Reporting Guidelines (March 2019); GHG Protocol — Scope 2 Guidance (2015). Verified 27 Sep 2026.
REGOs under a solar PPA
A PPA can deliver cheaper, cleaner power and still leave the certificates with someone else. Who ends up with the REGOs depends entirely on the contract, and the answer differs by structure.
| Structure | Where the REGOs arise | What the contract must say |
|---|---|---|
| On-site PPA | The provider's accredited station on your roof can claim REGOs on its gross output, including the units your building uses | That REGOs on the output you buy are transferred to you or cancelled in your name, not sold to someone else |
| Sleeved PPA | The remote farm's output | That the supplier delivering the power passes the farm's REGOs through to your supply, in the volume and period you need |
| Virtual PPA | The farm's output, which never reaches you | That the certificates are transferred to you separately, because no power changes hands |
The on-site row catches people out. It is tempting to assume that power generated on your roof and used in your building is automatically yours to call renewable. The GHG Protocol says otherwise: a company consuming energy directly from a generation facility that has sold its certificates forfeits the right to claim that generation, and has to report those units with a residual mix or replacement certificates instead. If your provider accredits the array and sells its REGOs, your renewable claim goes with them.
Who owns the REGOs under a solar PPA sets out the clauses to agree before you sign.
Sources: Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) (3.4, 5.10); GHG Protocol — Scope 2 Guidance (2015), 6.4–6.4.1. Verified 27 Sep 2026.
How much does a REGO cost?
There is no official REGO price. Ofgem issues REGOs to generators free of charge and does not set or publish a price: certificates change hands between Register account holders by private agreement, and the Register's public reports show accredited stations and each certificate's status and holder, not what anyone paid for it.
The nearest thing to an official figure is a written parliamentary answer. On 2 May 2025 the energy minister said the price fluctuates, but that "credible external estimates suggest that the latest spot market price is around £7 a certificate", and that with Ofgem issuing about 130 million certificates a year the market is worth around £910m annually. Treat that as a dated snapshot, not a quote for today.
Source: UK Parliament written answer UIN 47811, answered 2 May 2025. Verified 27 Sep 2026.
For a business the cost rarely appears as a separate line. It is built into the premium on a renewable tariff, or into the price of a PPA whose provider would otherwise have sold the certificates. That second point is worth remembering in a PPA negotiation: certificates the provider keeps are revenue to it, so asking for them can move the tariff.
REGOs and EU Guarantees of Origin after Brexit
Until Brexit, REGOs and EU Guarantees of Origin were interchangeable. That ended in two steps. From 1 January 2021 the EU stopped recognising UK REGOs. From the disclosure period beginning 1 April 2023, EU GoOs are no longer recognised for Great Britain's fuel mix disclosure, Feed-in Tariff levelisation or Contracts for Difference. Ofgem notes that EU GoOs remain valid for Northern Ireland's fuel mix disclosure.
For a business consuming electricity in Great Britain, the certificate that counts is therefore the REGO. How REGOs, GoOs and the international I-REC system relate is covered in energy attribute certificates compared.
Sources: Ofgem — REGO scheme; Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) (7.2). Verified 27 Sep 2026.
Is the REGO scheme changing?
Not yet. As of September 2026 no change to the REGO rules has been decided, but the direction of travel is towards finer time-matching.
- The Department for Business and Trade and DESNZ ran a call for evidence on corporate power purchase agreements from 9 January to 6 March 2026, on how to develop the corporate PPA market in Great Britain. The government response, published on 7 July 2026, records respondents calling for time-matched certificates, without making a decision.
- The government's Clean Flexibility Roadmap (July 2026 update) says DESNZ will continue to consider next steps on how certificates interact with flexibility, with an update due in the third quarter of 2027.
- The GHG Protocol consulted from October 2025 to January 2026 on revising its Scope 2 rules, including hourly matching. In July 2026 it announced that Scope 2 will be folded into a joint standard with ISO, with a further consultation planned for 2027 and publication in late 2028. Nothing has been adopted yet.
For a business signing a long PPA today, the practical step is to make sure the contract can pass through certificate data at whatever granularity future rules require, not just an annual volume.
Sources: DBT/DESNZ — Corporate Power Purchase Agreements call for evidence; DESNZ — Clean Flexibility Roadmap, July 2026 update; GHG Protocol — standard development update, July 2026. Verified 27 Sep 2026.
How to check a REGO claim
- Ask for the evidence, not the marketing. For carbon reporting that is Ofgem's cancellation letter naming your organisation as the beneficiary. For a supplier's tariff, ask how many REGOs were redeemed against your supply and for which disclosure period.
- Check the station. The Register's Accredited Stations report lists every station accredited for REGOs, so you can confirm that the station named in your contract is accredited.
- Check the certificates. The Certificates report, updated daily, shows each REGO's status (issued, redeemed, cancelled or revoked) and its registered holder.
- Match volume and period. The certificates should cover the megawatt-hours you are claiming, for generation in the period you are reporting.
- On a PPA, read the clause. The contract should name who holds the REGOs, when they are transferred or cancelled for you, and what happens if the station loses accreditation.
Sources for the figures on this page
| Figure on this page | Value | Source | Verified |
|---|---|---|---|
| REGO unit | One certificate per MWh of eligible renewable output | Ofgem — REGO | 27 Sep 2026 |
| Legal basis | Electricity (Guarantees of Origin of Electricity Produced from Renewable Energy Sources) Regulations 2003 | S.I. 2003/2562 | 27 Sep 2026 |
| On-site use | REGOs claimed on gross generation, including electricity used on site | Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) | 27 Sep 2026 |
| Shelf life | GB REGOs cancelled 16 months after the month of generation | Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026) | 27 Sep 2026 |
| Fuel mix disclosure | Period 1 April–31 March; evidence by midday 1 July; disclosure by 1 October | Ofgem — REGO Guidance for Generators, Agents and Suppliers, v4.0 (9 March 2026); S.I. 2005/391 | 27 Sep 2026 |
| EU Guarantees of Origin | Not recognised for GB fuel mix disclosure from 1 April 2023 | Ofgem — REGO | 27 Sep 2026 |
| Certificates sold from on-site generation | Consumer forfeits the renewable claim on those units | GHG Protocol Scope 2 Guidance, 6.4.1 | 27 Sep 2026 |
Frequently asked questions
What is a REGO certificate?
A REGO, or Renewable Energy Guarantee of Origin, is an electronic certificate Ofgem issues for each megawatt-hour of eligible renewable electricity an accredited generating station produces. It records the station, technology and period of generation.
What exactly are REGOs used for?
Mainly fuel mix disclosure: electricity suppliers hold REGOs to evidence the renewable share of the power they supplied. Ofgem also recognises their use in voluntary sustainability disclosure and carbon reporting, where they are voluntarily returned for cancellation in the consumer's name.
What is the compliance period for REGOs?
For fuel mix disclosure in Great Britain the period runs from 1 April to 31 March. Suppliers must hold the REGOs for that year's generation by midday on 1 July, and disclose their fuel mix by 1 October. Any GB REGO not used is cancelled 16 months after the month of generation.
How do you get a renewable energy certificate?
A generator gets REGOs by having its station accredited by Ofgem and submitting output data. A business that does not generate gets the benefit through its supplier, by buying a REGO-backed supply, or through a PPA that transfers the generator's REGOs to it.
Can a business hold REGOs itself?
Yes. The regulations let a registered holder transfer a REGO to any other person, and Ofgem's Register is used by generators, suppliers, traders and other participants through their own accounts. The simpler route for most businesses is to have the supplier or PPA provider cancel the REGOs in the business's name, which produces an Ofgem cancellation letter.
Do REGOs prove my electricity is renewable?
They prove that renewable megawatt-hours equal to your use were generated and claimed for you. They do not prove that the power reached your meter, that it was generated at the same time you used it, or that your purchase caused new generation to be built.
Do I get REGOs with a solar PPA?
Only if the contract says so. On-site arrays can earn REGOs on all their output, including the units your building uses, so the PPA should state that those REGOs are transferred to you or cancelled in your name.
How much does a REGO certificate cost?
There is no official price. REGOs are issued free to generators and then traded privately. In a written answer to Parliament on 2 May 2025 the energy minister cited external estimates of around £7 a certificate at the spot price, while noting that prices fluctuate.
Are REGOs the same as Guarantees of Origin?
A REGO is the UK form of a guarantee of origin, but the two are no longer interchangeable. The EU stopped recognising UK REGOs from 1 January 2021, and EU GoOs have not counted for Great Britain's fuel mix disclosure since the period beginning 1 April 2023.
Related on this site
Get an indicative PPA tariff for your site
A 60-second form gives us enough to match your site to vetted providers and return an indicative p/kWh tariff within one working day.
Get an indicative PPA tariffAsk us what a PPA would cost at your site
REGO certificates: what they are and how they work in the UK — tell us about your site and we'll return an indicative p/kWh tariff for it. Reply by email within one working day.