What a REGO is
Ofgem runs the Renewable Energy Guarantees of Origin scheme for the Department for Energy Security and Net Zero in Great Britain, and for the Utility Regulator in Northern Ireland. Renewable generators such as wind farms, solar parks and hydro plants are issued one REGO for every megawatt hour (1,000 kWh) of eligible electricity they produce.
The certificate is a record that the renewable generation happened. Its main job is fuel mix disclosure: licensed electricity suppliers must tell their customers, every year, the mix of coal, gas, nuclear, renewable and other sources behind the electricity they supply, and REGOs are how they evidence the renewable share. A REGO-backed renewable tariff means the supplier holds enough certificates to match what its customers on that tariff use.
What your green tariff actually buys
| It does | It doesn't |
|---|---|
| Allocate renewable generation to you on paper, so nobody else can claim the same megawatt hours | Change the physical electricity reaching your building, which is the same grid mix as everyone else's |
| Let you report zero market-based Scope 2 for the supply it covers | Change your location-based Scope 2, which a PPN 006 Carbon Reduction Plan reports |
| Show demand for renewable power | On its own, prove your money paid for a new wind or solar farm. A REGO certifies generation, not when the plant was built or who funded it |
There's another side to the allocation. Once REGO-backed electricity has been claimed, what's left for everyone else is dirtier. The government's fuel mix disclosure data for April 2025 to March 2026 puts renewables at 48.0% of all UK electricity supplied, but only 10.8% of the "residual" mix that suppliers use for electricity not backed by certificates, which is 65.3% natural gas.
A worked example
An office uses 30,000 kWh of electricity in 2026 on a tariff backed by REGOs for the whole supply.
| Figure | 30,000 kWh, tCO2e | After cutting 5,000 kWh, tCO2e |
|---|---|---|
| Scope 2, location-based | 3.93 | 3.27 |
| Scope 2, market-based | 0.00 | 0.00 |
| Scope 3: grid losses and fuel for generation | 1.60 | 1.34 |
The tariff brings the market-based figure to zero but leaves the other two untouched. Cutting 5,000 kWh, through LED lighting, controls or switching equipment off, lowers every figure that measures what the grid actually has to generate for you, by 0.92 tonnes in all. The electricity emission factor page has the grid factor for every year.
How to check what you're buying
- Ask for confirmation in writing that REGOs cover 100% of your supply for your reporting period, not "up to" or "on average across our customers".
- Read the supplier's fuel mix disclosure. If it doesn't show a separate mix for your tariff, ask for one.
- Check the dates. Certificates should relate to generation in the period you're reporting.
- Keep the evidence with your bills, so anyone checking your market-based figure can follow it.
Options that go further than certificates
- Using less. Cuts both Scope 2 figures, the Scope 3 parts and your bills.
- Generating your own. Solar panels on your roof displace electricity you'd otherwise buy from the grid, so the power you use from them never reaches your meter.
- Buying directly from a named project. Some buyers sign a power purchase agreement with a specific wind or solar farm, which ties the electricity and its certificates to a named source rather than the general market.
What's being debated
The GHG Protocol is revising its 2015 Scope 2 Guidance. Its consultation, which ran from October 2025 to January 2026, proposed that large organisations match certificates to their use hour by hour, and that certificates come from somewhere the power could physically reach them. Its July 2026 feedback summary reported low support for both proposals as drafted, an exemption for smaller organisations that drew broad support, and a decision by its Independent Standards Board to explore several market-based approaches before any further consultation. Until a new version is published, annual certificates like REGOs remain valid for market-based reporting. Our post on location-based and market-based Scope 2 covers which figure goes in which report.
How Carbon Recycling helps
Carbon Recycling calculates both Scope 2 figures from the same bills. Tick the renewable box on an electricity entry only when your supplier can show REGOs, or enter your supplier's own fuel mix factor, and the market-based figure updates while the location-based figure stays on the grid average. Your Carbon Reduction Plan reports location-based, as PPN 006 expects, so the reductions it shows are real cuts in electricity use rather than certificates. If you haven't measured yet, the free kWh to CO2e calculator converts a year of bills in seconds.