Biogas
What is Biogas?
Biogas is a renewable energy source produced when organic materials such as agricultural waste, manure, food waste or crop residues are broken down by microorganisms in the absence of oxygen.
The process — known as anaerobic digestion — generates a combustible gas primarily composed of methane (CH₄) and carbon dioxide (CO₂).
In agricultural settings, biogas transforms farm waste into usable energy, helping farms reduce emissions, lower reliance on fossil fuels and diversify income streams.
Biogas is a central component of circular agriculture and climate-smart farming systems.
What Is Biogas Made Of?
Biogas typically consists of:
Methane (50–70%) – the energy-rich component
Carbon dioxide (30–50%)
Small traces of hydrogen sulphide, water vapour and other gases
The methane content determines its energy value. When upgraded and purified, biogas becomes biomethane, which can be injected into gas grids or used as transport fuel.
How Is Biogas Produced?
Biogas is generated through anaerobic digestion, where organic matter decomposes inside sealed digesters without oxygen.
Common agricultural feedstocks include:
Livestock manure and slurry
Crop residues
Silage crops
Food waste
Agricultural by-products
The outputs of the process are:
Biogas (used for electricity, heat or fuel)
Digestate (used as organic fertiliser)
How Is Biogas Used?
1. Electricity Generation - Biogas fuels combined heat and power (CHP) engines to generate electricity.
2. Heat Production - Used for on-site heating in farm buildings or industrial facilities.
3. Vehicle Fuel - Upgraded biomethane can power farm vehicles and commercial fleets.
4. Grid Injection - Biomethane can be fed into national gas networks.
Why Biogas Matters in Agriculture
Emissions Reduction - Captures methane that would otherwise escape into the atmosphere.
Waste Recycling - Converts organic waste into energy and fertiliser.
Farm Diversification - Provides additional income streams through energy production.
Soil Health - Digestate returns nutrients to farmland, supporting nutrient cycling.
Policy Alignment - Supports Net Zero targets and renewable energy strategies.
Biogas in the UK
The UK biogas sector has grown significantly due to:
Renewable energy incentives
Net Zero commitments
Biomethane grid injection projects
Environmental Land Management (ELM) alignment
Sustainable Farming Incentive (SFI) objectives
Farm-based anaerobic digestion plants are particularly common in:
Dairy operations
Mixed livestock farms
Food processing sites
The UK is considered one of Europe’s leading agricultural biogas markets.
Biogas in Europe, USA & Globally
Europe
Germany and Denmark are leaders in agricultural biogas production. The EU Renewable Energy Directive promotes biogas as part of its energy transition strategy.
United States
The USDA supports biogas through climate-smart agriculture initiatives and dairy digester programmes. The US biogas sector continues to expand rapidly.
Global
The FAO, World Bank and International Renewable Energy Agency (IRENA) promote biogas as a sustainable energy solution, particularly in rural and developing regions.
Biogas vs Biomethane
Feature | Biogas | Biomethane |
|---|---|---|
Composition | Raw gas mixture (methane + CO₂) | Purified methane |
Processing Level | Minimal | Upgraded and refined |
Typical Use | On-site electricity & heat | Grid injection or vehicle fuel |
Energy Quality | Lower | Comparable to natural gas |
Biogas is the raw renewable gas.
Biomethane is the upgraded, higher-purity version.
Related Terms
Biomethane
Renewable Energy
Carbon Farming
Frequently Asked Questions (FAQs) on Biogas
What is biogas in simple terms?
Biogas is a renewable gas produced from organic waste through anaerobic digestion. It can be used to generate electricity, heat or fuel.
Is biogas environmentally friendly?
Yes. Biogas reduces methane emissions, recycles waste and replaces fossil fuels, helping lower greenhouse gas emissions.
What is the difference between biogas and biomethane?
Biogas is the raw gas produced from anaerobic digestion, while biomethane is purified biogas upgraded to natural gas standards.
Can farms produce their own biogas?
Yes. Many farms operate anaerobic digestion systems that convert manure and crop waste into renewable energy.
Does biogas reduce carbon emissions?
Yes. Capturing and using methane prevents it from entering the atmosphere and reduces reliance on fossil fuels.
Is biogas part of Net Zero farming?
Yes. Biogas is considered a key tool in achieving agricultural Net Zero targets by reducing emissions and generating renewable energy.
Key Resources on Biogas
Learn the meaning of more essential agricultural terms with our easy-to-use Key Terms Glossary here
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