The Department for Energy Security and Net Zero (DESNZ) has announced plans to extend the commissioning deadline of the Green Gas Support Scheme (GGSS) from 31 March 2028 to 31 March 2030, providing additional time for anaerobic digestion (AD) plants processing organic waste to begin injecting biomethane into the gas grid.

Lord Alan Whitehead, Minister of State at DESNZ, announced the extension at the Anaerobic Digestion and Bioresources Association (ADBA) National Conference in Westminster yesterday (10 December), with the new regulations expected to come into effect in early 2026, subject to parliamentary scrutiny.

The deadline for submitting new stage 1 applications will remain 31 March 2028. Applicants who commission beyond 31 March 2028 will receive a shortened tariff period, with payments ending by 31 March 2043 rather than the standard 15-year duration.

Industry response to the extension

Chris Huhne, Chair of ADBA and former Secretary of State for Energy and Climate Change, said: "This is exactly the certainty the industry needed. Today's announcement demonstrates that the Government recognises the critical role biomethane plays in delivering net zero and bolstering the UK's energy security."

Huhne added: "By extending the Green Gas Support Scheme, ministers are ensuring that investment can continue to flow and that new plants can continue to come online, delivering clean, reliable, home-grown gas. We now look forward to working with DESNZ on the long-term framework that will allow this industry to reach its full scale deployment."

ADBA has repeatedly raised concerns about a policy cliff-edge as older support schemes expire, warning that hundreds of AD plants face closure risk as subsidies are phased out. A survey conducted by the trade body in late 2024 indicated that over 160 plants are expected to come to the end of their existing support schemes within the next five years.

The extension is particularly relevant for operators seeking to secure waste feedstock contracts, as the GGSS requires that at least 50 per cent of biomethane output must be derived from waste or residue materials. The rollout of separate food waste collections under Simpler Recycling is expected to increase organic waste availability for AD operators, though implementation timescales vary across local authorities.

Scheme background and expected outcomes

The GGSS provides tariff support for plants producing biomethane via anaerobic digestion for injection into the gas grid, funded by the Green Gas Levy applied to licensed fossil fuel gas suppliers. The scheme opened in November 2021, following the closure of the Non-Domestic Renewable Heat Incentive Scheme.

According to government projections, the GGSS is expected to contribute 10.7 million tonnes of CO2 equivalent in carbon savings over its lifetime through the displacement of natural gas. During peak production years, biomethane plants incentivised by the scheme will produce enough green gas to heat around 250,000 homes.

DESNZ issued a call for evidence on a Future Policy Framework for Biomethane Production in February 2024, indicating that combined support from the Renewable Transport Fuel Obligation, GGSS and the Renewable Heat Incentive is expected to support around 8 TWh of biomethane injections by 2030. The government's Biomass Strategy has outlined a requirement for 30-40 TWh of biomethane production by 2050 to help achieve net zero cost-effectively.

Organic waste processing capacity

The UK's anaerobic digestion industry currently processes approximately 36 million tonnes of organic waste annually, according to ADBA, diverting material from landfill and capturing methane that would otherwise be released into the atmosphere. In doing this, the sector produces an estimated 21 TWh of biogas each year, either used to generate electricity and heat via combined heat and power units or upgraded to biomethane for grid injection.

Research commissioned by ADBA found that greater use of green gas could reduce UK net zero spending by £298 billion, with biomethane offering an alternative to offshore and onshore wind investment while providing a carbon-neutral energy source that can be stored in existing gas infrastructure.

The extension announcement comes amid continued uncertainty for parts of the sector, with older support schemes including the Feed-in Tariff and Renewable Obligation Certificates no longer accepting new applicants. Over 400 plants are expected to reach the end of their support periods in the next ten years.

Applicants who applied before 10 December 2025 will need to retain their original commissioning date or withdraw and resubmit. Those who submit stage 1 applications on or after 10 December but before the regulations come into force must apply with a commissioning date no later than 31 March 2028, though this may be revised once the new rules take effect.