Anaerobic Digestion

Anaerobic digestion (AD) is a biological process that breaks down organic materials, such as food waste, sewage sludge, manure, crops, and crop residues, in an oxygen-free environment. Microorganisms decompose these materials through a series of biological reactions, producing biogas. This biogas typically comprises 50–70% methane (CH4) and 30–50% carbon dioxide (CO2), with trace amounts of other gases. The solid or liquid by-product, known as digestate, is commonly used as a fertiliser, providing nutrients and organic matter to soil and crops, much like manure.

Biogas and biomethane are flexible sources of renewable energy, primarily used for electricity generation, heating, and as a transport fuel. Biogas can be combusted on-site with the respective outputs being used internally, adjacent or exported for wider distribution, whilst biomethane can be injected into the gas grid, to decarbonise heat and industry in turn, or used for transport in place of liquified or compressed natural gas.

The UK anaerobic digestion (AD) industry has expanded rapidly over the past two decades, influenced ultimately by waste and renewable energy policies, and the financial support mechanisms implemented across the UK to decarbonise the energy system.

With over 700 AD facilities now operating across the UK, and a subset of those injecting biomethane into the gas grid, the industry has moved from emerging to firmly established in recent years. However, growth potential remains vast and biomethane remains vital to the net zero energy transition.

Biomethane production from AD is already being deployed at scale, delivering improved energy security and genuine carbon savings. Given recent moves to improve the economics, reduce emissions and deliver greater circularity, the technology also has the potential to deliver greater impact in the coming decades. As the support landscape has changed and the original incentive mechanisms have closed to new applications, the Green Gas Support Scheme (GGSS) and the future policy landscape are set to be instrumental in stimulating future growth.

With an unrivalled knowledge of the UK AD market, Alder Bioinsights has supported many businesses as they look to enter into or expand in the market, to diversify current activities and to grasp new opportunities. Alder Bioinsights also works closely with both Government and industry, to develop the evidence base to inform policy decisions, and to translate policies and compliance requirements at site- and sector-level.

AD Market Reports

Our annual reports Anaerobic Digestion Deployment in the UK and Anaerobic Digestion Deployment in the Republic of Ireland provide a comprehensive breakdown of sector development, extensive market data and an in depth overview of policy and incentives. These are available to purchase individually or as part of a wider support package.