TL;DR:
- Green gas tariffs are backed by Renewable Gas Guarantees of Origin (RGGOs), which certify that biomethane equivalent to your usage has been injected into the grid — you don’t get different molecules, just a certificate.
- Biomethane production in the UK has grown significantly since 2024, but still represents a small fraction of total gas consumption, so green gas tariffs involve offsetting, not direct supply.
- If you’re still on gas and want to reduce your footprint while planning a heat pump transition, a green gas tariff is one option — but insulation and electrification do more.
Most UK households on the gas grid have little choice about what gas flows through their pipes. The grid is a single interconnected system. But energy suppliers can now offer “green gas” tariffs backed by guarantees that biomethane equivalent to your consumption has been injected elsewhere in the network. Understanding what that actually means — and what it doesn’t — helps you decide whether a green gas tariff is worth paying a premium for.
What Is Biomethane?
Biomethane is essentially the same molecule as natural gas (methane), but produced from biological sources rather than fossil reserves. The main production route in the UK is anaerobic digestion (AD): organic materials — agricultural waste, food waste, sewage sludge, energy crops — are broken down by bacteria in sealed tanks, producing biogas. That biogas is then upgraded by removing CO2 and other components to produce high-purity biomethane, which is injected into the gas distribution network.
There are over 700 AD plants connected to the gas grid in the UK as of 2026, with biomethane production growing steadily since the Green Gas Support Scheme (GGSS) replaced the Renewable Heat Incentive in 2022. The GGSS pays a tariff to biomethane producers for each kilowatt-hour injected, providing long-term revenue certainty that has supported new plant development.
Biomethane is considered low-carbon because the CO2 released when it burns was recently absorbed from the atmosphere by the feedstock crops or organic matter — unlike fossil gas, where carbon has been locked underground for millions of years. The lifecycle carbon figure varies significantly by feedstock and production method, but is generally 70—90% lower than natural gas.
How Green Gas Tariffs Work
When you sign up for a green gas tariff, your supplier doesn’t pipe different gas to your boiler. The physical gas grid doesn’t work that way. What happens is a certificate-based accounting system using Renewable Gas Guarantees of Origin (RGGOs).
Biomethane producers register with a certification body (currently Ofgem administers the UK RGGO scheme). For each MWh of biomethane injected, they receive one RGGO certificate. Energy suppliers buy these certificates and retire them against customer consumption on green gas tariffs. When you use 10,000 kWh of gas in a year on a green gas tariff, your supplier retires RGGOs certifying that 10,000 kWh of biomethane entered the grid somewhere.
This is the same model used for Renewable Energy Guarantees of Origin (REGOs) in electricity — your “renewable electricity” is also a certificate system, not dedicated green electrons.
Which Suppliers Offer Green Gas Tariffs in 2026?
Several UK suppliers offer 100% green gas tariffs or green gas add-ons:
Ecotricity has offered 100% green gas for over a decade and owns AD plants that inject into the grid. They have been investing in additional biomethane capacity to back their tariff with domestically-produced gas specifically rather than purely traded certificates.
Green Energy UK offers a 100% green gas tariff alongside their renewable electricity products. They source RGGOs from UK producers.
Octopus Energy offers a green gas add-on to their tariffs. Their Green Octopus tariff includes renewable electricity; adding green gas is an optional extra at a premium on the per-unit rate.
Bulb (now part of Octopus following the administration) previously offered 100% green gas and that product has been retained under the Octopus umbrella.
E.ON Next and EDF offer green tariffs that include green gas elements, though the exact RGGO backing percentages vary by product.
The Ofgem Confidence Code for green tariffs provides a framework for how suppliers must substantiate green claims, though it is voluntary. When comparing tariffs, check whether the supplier publishes which certification scheme backs their RGGOs and whether they’re 100% offset or a partial green contribution.
The Price Premium
Green gas tariffs typically cost 1—3p per kWh more than equivalent non-green tariffs, translating to roughly £100—£300 per year extra for an average UK home (using around 11,500 kWh of gas annually). The premium has narrowed slightly in 2025—2026 as biomethane production has scaled, but green gas remains more expensive than standard supply.
Some suppliers bundle green gas with renewable electricity, making it difficult to compare on gas alone. Get quotes in pence-per-kWh and standing charge terms to make a like-for-like comparison.
The July 2026 energy price cap puts the standard gas unit rate at around 6.24p/kWh. A green gas tariff at 7.5—8p/kWh is materially more expensive but may still be lower than it was during the 2022—2023 energy crisis peak.
Is a Green Gas Tariff Worth It?
For carbon reduction: A green gas tariff reduces your household’s carbon accounting, but it’s worth keeping the limitations in perspective. The certificate system means the biomethane was going to be produced and injected regardless of whether you’re on a green tariff or not — the demand signal from certificates does support producer investment at the margin, but you’re not directly enabling new production by signing up.
Switching from a gas boiler to a heat pump has a much larger impact on your actual emissions than greening the gas you continue to burn in your boiler.
For transition planning: If you’re planning to install a heat pump in the next 2—3 years and want to reduce your footprint in the interim, a green gas tariff is a reasonable holding position. It’s not a substitute for electrification, but it’s a lower-cost way to improve your carbon position while you save for or wait for the right upgrade timing.
For landlords and businesses: Green gas tariffs can support sustainability reporting and building-level emissions accounting. They’re recognised in the GHG Protocol Scope 2 framework for gas in the same way REGOs are used for electricity.
The Bigger Picture: UK Biomethane’s Ceiling
The UK’s Climate Change Committee has assessed that biomethane can realistically supply around 20—25% of residential gas demand in a decarbonised scenario — not all of it. The feedstock base (agricultural waste, food waste) has limits, and land competition with food production constrains energy crop use. This means green gas tariffs, even if widely adopted, cannot by themselves decarbonise home heating.
The government’s trajectory remains: get homes off gas boilers via heat pumps and heat networks, with the gas grid potentially surviving in a reduced form for industrial uses and potentially hydrogen. The Boiler Upgrade Scheme, Warm Homes Local Grant, and the planned Future Homes Standard (requiring heat pumps in new builds from 2026) all point in this direction.
A green gas tariff is a bridging measure, not an endpoint.
Practical Steps
- Check your current tariff: Log into your supplier account or check your bill. Many customers are on standard variable tariffs that have no green component.
- Compare with a green tariff: Use a comparison site filtering for green gas tariffs; check whether the RGGO backing is 100% and from UK production.
- Calculate the annual premium: Multiply the pence-per-kWh difference by your annual gas consumption (from last year’s bill).
- Consider your upgrade timeline: If a heat pump is likely within 2 years, weigh the premium against other uses of that budget (insulation, controls, hot water cylinder upgrade).