What is a green energy tariff UK?

A green energy tariff in the UK means your electricity is matched by Renewable Energy Guaranty of Origin (REGO) certificates — each REGO represents 1 MWh of electricity generated from a renewable source. When a supplier offers '100% renewable electricity', they are typically buying REGOs to match your consumption. However, the electricity that actually flows through your meter comes from the national grid, which is a mix of sources. The distinction matters: some suppliers own their own renewable generation (Octopus, Good Energy, Ecotricity); others simply buy REGOs on the open market to make a claim.

Which energy supplier is the most green UK?

The greenest energy suppliers in the UK in 2026 based on their actual renewable generation (not just REGO certificates) include: Ecotricity (the UK's first and most established green energy company — 100% renewable; funds new green energy construction); Good Energy (100% renewable; longest-standing dedicated green supplier; 4.4/5 Which? score); Octopus Energy (100% renewable electricity; significant owned generation via Octopus Energy Generation; largest UK wind investor). Scottish Power's green tariff is backed by its own wind farms — the first major supplier to generate 100% for green tariffs from owned wind assets.

What is the difference between REGO and genuine renewable energy?

REGOs (Renewable Energy Guaranty of Origin certificates) are certificates purchased by energy suppliers to claim their electricity is from renewable sources. A REGO costs approximately £1-£2 per MWh — so matching 3,000 kWh of household electricity costs only £3-£6. This means almost any supplier can claim 'green' electricity cheaply. Genuine green electricity means the supplier either owns renewable generation assets, has long-term power purchase agreements directly with specific UK renewable generators, or builds new renewable capacity. Good Energy and Ecotricity are the gold standard here; Octopus is strong; most other 'green tariff' claims are largely REGO-washing.

Green Energy Tariffs UK 2026: 100% Renewable Electricity

Q: Are green energy tariffs more expensive?

Green energy tariffs were historically more expensive than standard tariffs. In 2026, this is no longer necessarily true. Octopus Energy offers 100% renewable electricity as standard on all its tariffs — including its cheapest options, which are often below the Ofgem price cap. You do not need to pay a premium for green electricity if you switch to Octopus. Ecotricity and Good Energy, which are 100% dedicated green suppliers, may charge slightly more than the cheapest comparison-site deals — but the premium has narrowed significantly in recent years.

Green Energy Tariffs UK 2026: Are They Worth It?

Chandraketu Tripathi

Finance Editor, Kaeltripton

Published 4 Apr 2026

Last reviewed 9 May 2026

✓ Fact-checked

Part of: Best Energy Suppliers UK 2026

'100% renewable electricity' claims are everywhere in energy tariff marketing — but what do they actually mean? And which suppliers are genuinely green? Here's the complete 2026 guide. Updated April 2026

What 'Green Energy' Really Means — The REGO System

When electricity flows from a renewable source (wind farm, solar panel, hydro plant) into the national grid, the generator receives one REGO certificate per MWh. Energy suppliers can buy these REGOs separately from the electricity itself — at very low cost (approximately £1-£2/MWh). By buying enough REGOs to match their customers' consumption, they can legally claim to supply '100% renewable electricity'. This is not fraud — it is the official Ofgem-recognised system. But it does mean that a supplier paying £5/year in REGOs can claim the same '100% renewable' label as a supplier that has invested millions in building wind farms.

Suppliers Ranked by Green Credentials — 2026

Supplier	Renewable Claim	Owned Generation?	REGO Only?	Verdict
Ecotricity	100% green + wind gas	Yes — Ecotricity builds its own wind farms	No	Gold standard — funds new generation
Good Energy	100% renewable	Yes — long-term contracts with specific UK farms	No	Gold standard — genuine renewable matching
Octopus Energy	100% renewable	Significant — Octopus Energy Generation (major UK wind investor)	Partly	Genuinely strong; largest UK wind investor
Scottish Power (green tariff)	100% renewable	Yes — first major to use own wind for green tariff	No	Strong for a large supplier
E.ON Next	100% renewable (some tariffs)	Some owned generation; also REGOs	Partly	Reasonable — better than pure REGO
British Gas (green options)	100% renewable (select tariffs)	Minimal owned renewable generation	Largely yes	REGO-reliant — weaker claim
EDF Energy (green tariffs)	100% low carbon/renewable	Significant nuclear + wind — genuinely low carbon	Partly	Strongest on low-carbon; less on renewable
Most other suppliers	'100% renewable'	None owned	Yes — pure REGO	Weakest — REGO-washing

Is a Green Tariff Worth Paying Extra For?

The answer depends on what you are trying to achieve. If you want to reduce your carbon impact financially — any renewable tariff (even REGO-only) sends a market signal and funds the renewable sector. Every REGO purchase supports a renewable generator financially, even if by a small amount. If you want to maximise genuine impact — choose Ecotricity or Good Energy, which directly fund new UK renewable generation with their customers' bills. If you want to pay the least while being green — Octopus Energy offers 100% renewable electricity on its cheapest tariffs. There is no premium to pay. The case for paying extra for a 'greener' supplier has weakened because Octopus's cheap tariffs are already green. The case for Ecotricity or Good Energy remains if new capacity funding is your priority.

What Is the Greenest Energy Tariff Available in April 2026?

Supplier	Typical Annual Cost	Green Credential	Best For
Ecotricity	Slightly above cap	Funds new UK wind and solar; green gas	Most committed to green transition
Good Energy	Slightly above cap	100% UK renewable; long-term farm contracts	Transparency + renewable purity
Octopus Energy (standard fix)	£1,480-£1,620 (below cap)	100% renewable; major wind investor	Best value + genuine green credentials
Scottish Power (green tariff)	At or near cap	Own wind farms	Traditional supplier with genuine generation

KAELTRIPTON VERDICT

Most '100% renewable' energy tariffs in 2026 are REGO-based — certificates bought cheaply to make a marketing claim. The genuinely green suppliers are Ecotricity and Good Energy (build new renewable capacity) and Octopus Energy (major wind investor, 100% renewable on cheapest tariffs). For most households, Octopus delivers the best combination of green credentials, competitive price and customer service. If you specifically want to fund new UK renewable generation, Ecotricity is the gold standard.

Octopus: Cheapest + Genuinely Green — Ecotricity: Best for New Generation

Q: What does green energy tariff mean UK?

A: Your electricity is matched by REGO certificates (Renewable Energy Guaranty of Origin). Electricity still comes from national grid mix. Some suppliers own renewable generation; others just buy certificates cheaply.

Q: Which energy supplier is most green UK?

A: Ecotricity (builds own wind/solar); Good Energy (long-term UK renewable contracts); Octopus Energy (major wind investor; 100% renewable on all tariffs including cheapest).

Q: Are green energy tariffs more expensive?

A: Not necessarily — Octopus Energy offers 100% renewable on its cheapest tariffs, often below the Ofgem cap. Ecotricity and Good Energy may charge a small premium for fully funded new renewable generation.

Q: What is REGO?

A: Renewable Energy Guaranty of Origin certificate — 1 REGO = 1 MWh of renewable electricity. Costs ~£1-2/MWh. Most 'green tariff' claims are REGO-based. True green suppliers also own or fund generation.

This article is for informational purposes only. Energy prices change frequently — always compare on Uswitch or MoneySavingExpert for your current best deal. Figures verified April 2026 from Ofgem, Which?, Citizens Advice and Trustpilot.

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