The Green Gas Support Scheme (GGSS) is a government subsidy that pays new plants in Great Britain for producing biomethane through anaerobic digestion and injecting it into the gas grid. The payments are tariffs per unit of gas, designed to cover the cost of building a plant and running it. The Department for Energy Security and Net Zero sets the policy and Ofgem runs the scheme.
How it works
Anaerobic digestion breaks down food waste, manure or crops to make biogas, which is cleaned to grid quality as biomethane. A registered plant receives tariff payments for up to 15 years. The scheme opened on 30 November 2021 and replaced the non-domestic Renewable Heat Incentive for new biomethane projects.
It is paid for by the Green Gas Levy, charged to all licensed suppliers of fossil fuel gas. Spending is controlled by two budget caps, an annual tariff review and an automatic 10% tariff cut (degression) if quarterly spending thresholds are expected to be exceeded.
Key dates
| Milestone | Date |
|---|---|
| Scheme opened | 30 November 2021 |
| Last date for new stage 1 applications | 31 March 2028 |
| Commissioning deadline | 31 March 2030 (moved from 31 March 2028, in force from 16 October 2026) |
| All tariff payments end | 31 March 2043 |
The later commissioning deadline gives developers two more years to build plants, start injecting gas and complete their final (stage 3) application. It does not lengthen support: a plant commissioning after 31 March 2028 still stops receiving tariffs by 31 March 2043. The government’s example is a plant commissioning on 31 March 2030, which would get 13 years of payments rather than 15.
Why it matters
Biomethane is one of the few ways to cut emissions from the existing gas network without changing boilers or appliances. For households the effect is indirect: the gas reaches homes through the same pipes, and the levy is a cost on gas suppliers that can feed through to bills.
Read more: Biomethane plants get two more years to commission under the Green Gas Support Scheme.