Green Energy Tariffs UK: REGO-Backed, Generator-Backed and What to Check

A green energy tariff in Great Britain usually means your supplier matches the electricity you use with renewable generation, not that different electricity reaches your home. The two models worth knowing are REGO-backed tariffs, where the supplier holds certificates for renewable output, and generator-backed supply, where it also generates renewable power itself or buys it directly from renewable projects. Facts below were checked on 15 October 2026.

What makes an energy tariff green?

Citizens Advice says that a supplier calling a tariff "green" or "renewable" does not mean the energy you use always comes from renewable sources. The gas or electricity that reaches your home on a green tariff is the same as everyone else gets.

What the supplier does is match the amount of energy you use to a renewable source. Citizens Advice gives three ways a supplier might do that:

• generate its own renewable energy;
• invest in renewable energy sources;
• buy electricity from renewable energy projects.

Citizens Advice gives green standard variable, prepayment, fixed prepayment and dual fuel tariffs as examples, so going green does not have to mean changing how you pay.

What does REGO-backed mean?

A REGO is a Renewable Energy Guarantee of Origin. Ofgem issues one REGO certificate for each megawatt hour of eligible renewable output to generators of renewable electricity, in Great Britain and Northern Ireland. Their main use is fuel mix disclosure: licensed electricity suppliers must tell existing and potential customers the mix of fuels used to generate the electricity they supply.

The key detail is in Ofgem's REGO guidance, published on 9 March 2026: once issued, REGOs can be traded with or without the electricity they were issued for. So a supplier can buy certificates separately from the power it buys, and use them to show that renewable output matched its customers' use.

That is what a REGO-backed green tariff usually means. It is a matching claim, which is why the wording matters.

What does generator-backed mean?

Some suppliers go further than certificates. In Citizens Advice's terms, they generate their own renewable energy or buy electricity directly from renewable energy projects. Citizens Advice suggests that if you want a 100% renewable tariff, you check the wording of the tariff carefully, and that you could use a supplier that makes its own renewable energy, checking its website to see where it gets its energy from.

Suppliers describe their own sourcing in different ways, so compare what each says it does rather than the label on the tariff.

Are green tariffs covered by the price cap?

The price cap protects standard variable tariffs. A fixed green tariff sits outside it, like any fixed deal.

Some green variable tariffs are outside it too. Ofgem has granted enduring derogations that let named renewable standard variable tariffs from Ecotricity, Good Energy and Green Energy UK charge above the cap. Its decision on Ecotricity, dated 1 August 2019, says the directions stay in force for the lifetime of the cap unless Ofgem revokes or varies them, and that Ofgem has not assessed whether those tariffs give good value.

Citizens Advice says that on one of these green standard variable tariffs there is no limit on what you can be charged, and that if your rate rises too high you can switch to a different tariff at any time.

What should you check before switching to a green tariff?

1. How the supplier matches your use. Certificates bought separately, its own generation, or direct contracts with renewable projects.
2. The fuel mix. Electricity suppliers must disclose the mix of fuels behind the electricity they supply.
3. Whether the tariff is capped. Fixed tariffs are not, and some green variable tariffs are not either.
4. The yearly cost on your own usage. Include both standing charges, and compare with the cheapest tariff you would otherwise choose.
5. The contract terms. Ofgem says you may have to pay an exit fee if you leave a fixed tariff before it ends, and that you can cancel a switch within 14 days.
6. Your meter. Citizens Advice says you usually need a smart meter for a time-of-use tariff, so check before choosing a green tariff that varies by time of day.

If you rent and pay the supplier yourself, you can usually choose a green tariff like any other. Check your tenancy agreement first: our guide to setting up gas and electricity in a new home covers what to look for.

Does Taupia show green tariffs?

Yes, where the tariff data marks them. On Taupia's energy comparison, tariffs that the live tariff data flags as green carry a Green label. The label is the data provider's classification, so check the supplier's own fuel mix and tariff wording before you choose. For how standing charges and unit rates differ by area, see our price cap rates by region.

Where Taupia fits

Taupia monitors your energy bills, compares tariffs against your own usage and switches only once you approve. It is free, and it never guarantees a saving.