There are currently 750 municipal, commercial and agricultural AD plants operating across the UK, producing an estimated 21 TWh of biomethane annually, of which around 7 TWh is injected into the gas grid. But one of the National Energy System Operator's Future Energy Scenarios puts required biomethane production at 64 TWh by 2050 — a target that would require a significant expansion of the sector's current output.
The briefing, authored by Sophie Powell, comes as the House of Lords Environment and Climate Change Committee has called on government to assess whether AD plant capacity is keeping pace with household food waste volumes, now that weekly food waste collections have become mandatory for English local authorities as of March 2026.
The Committee also flagged concerns over fugitive methane emissions from digesters and storage tanks, recommending a review of regulatory oversight and consideration of mandatory leak assessments across all sites.
Methane capture and waste sector emissions
AD plants break down organic feedstock — including sewage sludge, agricultural waste, purpose-grown crops and food waste — using microbes in the absence of oxygen, producing biogas (a mix of methane and carbon dioxide) and a nutrient-rich fertiliser byproduct known as digestate.
The process captures methane that would otherwise be released from landfill sites; in 2022, the waste sector accounted for 31% of total UK methane emissions, while livestock and manure contributed a further 48%.
Food waste remains a key target for expanded AD capacity: households generate 58% of UK food waste, and 535,000 tonnes of separated food waste was collected by English local authorities in 2024.
The government has committed £295 million in capital funding to support specialist collection vehicles and food waste caddies as weekly collections roll out nationally.
Diverging views on feedstock policy
The briefing highlights ongoing debate over the sector's expansion. Charities and NGOs, including the StopTheBiomethaneRush coalition, have raised concerns that subsidies for AD may inadvertently incentivise food waste generation within the supply chain, potentially diverting edible surplus food away from redistribution — which sits above AD in the UK's food waste hierarchy.
Separately, the NGO Foodrise has argued that land used to grow purpose-grown AD crops could deliver greater climate benefit if used for other purposes, such as solar generation or woodland.
Researchers cited in the briefing note that scaling up AD remains economically challenging, as biomethane production costs currently exceed those of natural gas, with policy debate ongoing over whether government should pursue a producer-focused, state-driven model or a market-driven approach centred solely on biomethane pricing.
The briefing also outlines regulatory considerations for AD operators in England, including permitting requirements under the Environmental Permitting Regulations 2016, Animal By-Products Regulations, and duty-of-care obligations for digestate handling and land application.
