From One Million to Over 2 Million: The Extraordinary Journey Continues
Back in 2017, we celebrated a significant milestone when UK anaerobic digestion (AD) capacity had grown enough to power one million homes. At the time, we were cautiously optimistic about the industry's future, wondering if the rapid growth rate could be sustained.
Today, we're thrilled to report that the UK biogas sector has not only maintained its momentum but has achieved something truly remarkable – the capacity has doubled in 8 years, according to notes provided in the publication details of the latest Anaerobic Digestion and Bioresources Association Press Release.
The numbers tell an incredible story of growth and resilience. From 730 MWe-e in 2017, the UK now boasts about 750 operational commercial anaerobic digestion (AD) plants (not including water utility sludge digesters), with a suggested capacity of more than 2,800 MW of biogas for use as renewable heat, electricity or biomethane (green gas).
This represents a large increase in capacity over just 8 years, demonstrating that our initial doubts about sustained growth were thankfully unfounded.
Putting This Growth Into Perspective
To truly appreciate this achievement, let's put these figures into context. Our original article noted that powering one million homes was more capacity than the UK's Wylfa Power Station in Wales, which was closed for dismantling in 2017.
Now, with nearly 2.8 GW of capacity (Source: HRS Opinion Piece extrapolation), the UK's AD sector could theoretically power between 2 and 3 million homes – equivalent to powering every household in Wales, Northern Ireland.
This isn't just about raw numbers; it's about the transformation of the UK's energy landscape. As of 2025, the UK has over 1,000 operational AD plants (including sewage sludge digesters at Wastewater Treatment Facilities), showing that when we include all forms of anaerobic digestion, the sector has grown even more substantially.
The Energy Output Revolution
The energy generation figures are equally impressive. In the UK, it produces 21TWh of energy (ADBA PR Sept. 2025) – broadly equivalent to Scotland's annual electricity demand – and it is poised to surpass nuclear (~40TWh) as a low-carbon energy provider by 2029. This is a monumental shift from our 2017 baseline of 10.7 TWh per year, representing more than a doubling of actual energy output.
This growth trajectory positions anaerobic digestion as a cornerstone of the UK's renewable energy future, not just a supporting player.
What Changed Since 2017? The Policy Landscape Evolution
Our original article expressed concern about government policy uncertainty, particularly around subsidy reductions and the removal of support mechanisms.
While these challenges did materialise – the RHI scheme closed to new applicants in April 2021, and the Green Gas Scheme initially offered limited support – the industry has demonstrated remarkable adaptability and resilience.
The sector has evolved beyond its initial dependence on government subsidies, driven by several key factors:
1. Market-Driven Growth
Rising energy prices, particularly following the energy crisis that began in 2021, have made biogas economically viable without the level of subsidy support previously required. Natural gas price volatility has created a stable market for biomethane injection into the grid.
2. Technological Advancement
The efficiency improvements we noted in our original article have continued. Load factors have increased beyond the 73% reported in 2017, and plant reliability has significantly improved. Modern AD plants are now more sophisticated, with better feedstock handling, enhanced gas upgrading systems, and improved operational monitoring.
3. Diversified Revenue Streams
Today's AD plants don't rely solely on electricity generation. The sector has embraced biomethane production for grid injection, carbon dioxide capture for industrial use, and high-quality digestate as a soil improver. This diversification has created more robust business models.
The Environmental Impact Multiplier Effect
The growth in capacity has had a multiplicative effect on environmental benefits. Where our 2017 article noted that AD was reducing greenhouse gas emissions by 1%, the expanded capacity now delivers substantially greater emissions reductions.
The sector is not only preventing methane emissions from organic waste but actively contributing to carbon sequestration through digestate application to soils.
The CO2 shortage that made headlines in September 2021 highlighted another crucial benefit of AD – the production of food-grade CO2 as a by-product. With current capacity, the UK AD sector can provide a significant proportion of industrial CO2 requirements, reducing dependence on imported CO2.
Looking Forward: Meeting the UK's Full AD Potential
Despite this impressive growth, many in the UK biogas sector believe that the current capacity still represents only a fraction of the country's true potential. The fundamentals that made us optimistic in 2017 remain stronger than ever:
- Abundant Feedstock: The UK continues to produce millions of tonnes of organic waste annually that could be processed through AD, and in 2026, household food waste collections throughout England will, for the first time, add to the organic waste available
- Energy Security: The need for domestic energy production has never been more apparent
- Climate Commitments: The UK's net-zero targets require the rapid deployment of proven low-carbon technologies like AD
- Agricultural Benefits: Farmers increasingly recognise AD as a source of additional revenue and a solution for waste management
The Path from 500 MW to 2,800 MW: A Success Story
Reflecting on the journey from our 2015 milestone of 500 MW capacity reported by ADBA, through the 730 MWe-e celebrated in 2017, to today's 2,800 MW represents one of the UK's renewable energy success stories. This growth occurred despite policy headwinds, demonstrating the fundamental strength of the technology and its economic viability.
The increase from around 400 plants in 2015 to 750 operational facilities (not including Water Utility Co. sludge treatment digesters) today shows not just capacity growth but also geographic spread and technological diversity. The sector now encompasses everything from small farm-based digesters to large-scale food waste processing facilities and innovative energy-from-waste plants.
Employment and Economic Impact
While our 2017 article noted that AD employed more than 3,500 people, the expanded sector now supports 4,800 biogas industry jobs in the UK and doubtless many more across the supply chain (as estimated by ADBA in September 2025 in their PR Publisher Notes).
From equipment manufacturers and engineering consultants to operators and maintenance specialists, the AD sector has become a significant employer in rural and industrial communities across the UK.
Technical Innovations Driving Growth
The sector's growth has been supported by continuous technical innovation:
- Enhanced Gas Upgrading: Modern biomethane plants achieve higher efficiency in converting biogas to grid-quality gas
- Advanced Feedstock Preprocessing: Better preparation of input materials maximises gas yields
- Digital Monitoring: IoT sensors and soon, AI-driven optimisation, will be improving plant performance and reliability
- Modular Design: Standardised components have reduced costs and construction times
Challenges Overcome and Lessons Learned
The journey from 2017 to 2025 hasn't been without challenges. The industry navigated:
- Policy Uncertainty: The closure of the RHI and initial limitations of the Green Gas Scheme
- Planning Constraints: Local opposition and lengthy approval processes for some projects
- Supply Chain Issues: Component shortages and cost inflation affecting new builds
- Grid Connection: Challenges in connecting biomethane plants to the gas grid
However, each challenge drove innovation and resilience. The sector's ability to grow despite these headwinds demonstrates its fundamental strength and importance to the UK's energy mix.
The Future Outlook: Beyond 2025
As we look beyond 2025, the UK AD sector is positioned for continued growth. Government recognition of biogas as a “practical and cost-effective” solution for energy security, combined with increasing focus on waste management and circular economy principles, creates a favourable environment for further expansion.
The potential identified in our original article – approximately 3,000 MW from non-sewage waste biological matter, energy crops, food waste, and abattoir waste – remains largely untapped.
With current capacity at 2,800 MW, we're tantalizingly close to that initial estimate, suggesting the next phase of growth may require developing new feedstock sources or improving extraction efficiency from existing waste streams.
Conclusion: A Vision Realised and Exceeded
When we wrote about powering one million homes in 2017, it felt like a significant achievement. Today, with the capacity to power over 2 million homes, we can confidently say the UK anaerobic digestion sector has not only met but exceeded expectations.
This growth story demonstrates that with the right combination of technology, market conditions, and industry determination, renewable energy sectors can achieve remarkable scale rapidly. The UK's AD success provides a template for other countries looking to develop their biogas potential and a foundation for the UK's continued leadership in sustainable energy production.
The journey from 730 MWe-e to 2,800 MW represents more than just numbers – it's a testament to innovation, persistence, and the vital role that anaerobic digestion plays in the UK's sustainable energy future. As we move forward, the challenge shifts from proving the technology works to optimising its deployment and maximising its contribution to the UK's net-zero ambitions.
The one million home milestone of 2017 was just the beginning. The over two million home capacity of 2025 positions the UK AD sector as a cornerstone of the country's renewable energy infrastructure, ready to play an even larger role in the decades ahead.
This article represents an update to our original 2017 piece, “Anaerobic Digestion UK Capacity Enough to Power 1 Million Homes,” reflecting the remarkable growth and maturation of the UK biogas sector over the past eight years.
[Originally posted on 15 July 2017. Updated December 2021, and September 2025.]
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Claiming to sell a renewable product could increase the company s market share or initial sales enough to make it worth discontinuing past tactics of fossil fuel use, at least for a time. Is biogas actually renewable?