Biomethane is a renewable gas produced by purifying biogas until it contains a high concentration of methane. Because its composition and energy characteristics can be made similar to those of fossil natural gas, biomethane can be used in compatible gas networks, boilers, industrial processes and vehicles.
It is also called renewable natural gas (RNG), particularly in North America. In Britain and Europe, biomethane is the more commonly used term.
Biomethane is not the same thing as raw biogas. Biogas is the methane-and-carbon-dioxide mixture initially produced when microorganisms break down organic material without oxygen. Biomethane is the refined product obtained after much of the carbon dioxide, water and unwanted trace compounds have been removed.
Key Takeaways
- Biomethane is upgraded biogas. Carbon dioxide, water and contaminants are removed to produce a methane-rich renewable gas.
- It can replace fossil natural gas in compatible applications. Uses include gas-grid injection, industrial heat, boilers, heavy transport and energy storage.
- Waste and residue feedstocks usually offer the strongest sustainability case. Food waste, manure, sewage sludge and industrial organic residues can provide both waste-management and renewable-energy benefits.
- Renewable does not automatically mean carbon-neutral. The lifecycle result depends on feedstocks, processing energy, land use, digestate management and the fuel being displaced.
- Methane leakage must be controlled. Leaks from digesters, upgrading equipment, pipework and digestate storage can materially weaken the climate benefit.
- Biomethane is valuable but limited. It is best directed towards applications that are difficult to electrify rather than treated as an unlimited replacement for all fossil gas.
- Biomethane supplies renewable carbon as well as energy. In a net-zero economy, it could provide feedstock for chemicals and materials that cannot be produced from electricity and hydrogen alone.
Biomethane, Biogas and Natural Gas Compared
| Gas | Source | Typical characteristics | Common uses |
|---|---|---|---|
| Biogas | Anaerobic digestion of food waste, manure, sewage sludge and other organic material | Usually about 45% to 75% methane, with carbon dioxide, water vapour and trace contaminants | On-site heat, electricity and combined heat and power |
| Biomethane | Biogas that has been cleaned and upgraded | High methane concentration; commonly above 90% and further conditioned when pipeline injection is required | Gas-grid injection, heat, industry, transport and energy storage |
| Fossil natural gas (known as Natural Gas) | Underground geological deposits | Predominantly methane but derived from a finite fossil resource | Heating, electricity, industry, chemicals and transport |
The methane molecule in biomethane is chemically the same as methane in fossil natural gas. The important difference is its origin and lifecycle: biomethane is made from recently living organic material or organic waste, whereas fossil gas introduces carbon that has been stored underground for geological periods.
The International Energy Agency describes biomethane as a near-pure methane source produced mainly by removing carbon dioxide, water and other contaminants from biogas. Its similarity to natural gas allows it to act as a “drop-in” substitute in suitable applications.
Read the IEA introduction to biogas and biomethane.
Watch: What Is Biomethane?
This short video introduces biomethane and explains why upgrading biogas creates a flexible renewable fuel.
Video not displaying? Watch “What Is Biomethane?” directly on YouTube.
How Is Biomethane Made?
Most biomethane begins with anaerobic digestion. Organic material is placed inside a sealed digester, where naturally occurring microorganisms break it down in the absence of oxygen.
This process produces two main outputs:
- Biogas: a mixture containing methane, carbon dioxide, water vapour and smaller quantities of other gases.
- Digestate: the remaining nutrient-containing material, which may be processed and used as a fertiliser or soil amendment where regulations and its quality permit.
Raw biogas can fuel a boiler or combined heat and power engine after appropriate cleaning. Producing biomethane requires additional treatment known as biogas upgrading.
The Main Biomethane Production Stages
- Organic feedstock is prepared. Contaminants are removed and the feedstock may be mixed, shredded or diluted.
- Anaerobic digestion produces biogas. Microorganisms convert part of the organic material into methane and carbon dioxide.
- The raw gas is cleaned. Hydrogen sulphide, moisture and other undesirable compounds are removed or reduced.
- Carbon dioxide is separated. This raises the methane concentration and energy value of the gas.
- The biomethane is conditioned for its intended use. Further drying, compression, quality measurement or odourisation may be required.
Commercial upgrading technologies include water scrubbing, membrane separation, pressure swing adsorption, chemical absorption and cryogenic separation. Each has different energy requirements, methane-recovery performance, capital costs and suitability for particular plant sizes.
For a more detailed explanation, see:
What Is Biomethane Made From?
Biomethane can be produced, by the anaerobic digestion process, from many biodegradable materials, including:
- food and drink manufacturing residues;
- separately collected household and commercial food waste;
- livestock manure and slurry;
- crop residues and other agricultural by-products;
- sewage sludge;
- organic industrial wastes; and
- captured landfill gas.
Purpose-grown energy crops can also be digested, but their sustainability depends on land use, agricultural inputs, effects on food production and the alternative crops or habitats displaced.
Waste and residue feedstocks are therefore particularly important. They can combine renewable gas production with improved organic-waste management and, in some circumstances, the avoidance of methane that might otherwise escape from manure or decomposing waste.
The European Commission’s biomethane strategy specifically emphasises increased use of wastes and residues rather than food and feed crops because of the potential land-use consequences of crop-based production.
See the European Commission’s biomethane overview.
What Is Biomethane Used For?
Once upgraded to the necessary specification, biomethane can perform many of the same functions as fossil natural gas.
1. Injection into the Gas Grid
Biomethane can be injected into a gas distribution or transmission network when it meets the network operator’s requirements for composition, pressure, energy content and safety.
Grid injection allows renewable gas produced at one location to be used elsewhere without constructing a separate delivery network. The injected gas can support heating, industry or other applications connected to the system.
The engineering and regulatory requirements are covered more fully in What Is Biomethane and Anaerobic Digestion Gas to Grid?
2. Industrial Heat
Some manufacturing processes require controllable high-temperature heat that is difficult to provide directly with intermittent renewable electricity. Biomethane can replace some fossil gas in compatible industrial burners and boilers, although its best use depends on local alternatives, cost and availability.
3. Transport Fuel
Biomethane can be compressed to produce renewable compressed natural gas, commonly called bio-CNG or renewable CNG. It can also be liquefied to produce bio-LNG or liquefied biomethane.
These fuels are most relevant to vehicles that already use methane, particularly certain heavy-duty road fleets, buses, ships and specialist vehicles. Biomethane combustion is not pollution-free, but appropriate engines can produce lower particulate emissions than diesel alternatives.
4. Electricity and Combined Heat and Power
Biomethane can generate electricity or supply combined heat and power equipment. In many cases, however, raw biogas can already perform this function without the cost and energy consumption of full upgrading.
The decision to upgrade should therefore consider whether a higher-value gas-grid, transport or industrial use is available.
5. Renewable Carbon and Chemical Feedstock
Biomethane is more than a renewable fuel. It is also a potentially important source of renewable carbon for the chemical and materials industries.
Modern society depends on carbon-based products including plastics, resins, solvents, paints, coatings, adhesives, synthetic fibres, detergents, lubricants and pharmaceutical ingredients. Most of the carbon incorporated into these products currently originates in crude oil, fossil natural gas or coal.
Renewable electricity can replace much of the energy used by industry, and low-emission hydrogen can replace fossil hydrogen in many processes. However, neither electricity nor hydrogen supplies the carbon atoms needed to manufacture organic chemicals and carbon-based materials.
In a net-zero and increasingly circular economy, that carbon will need to come from a combination of:
- sustainably produced biomass and biomethane;
- recycled plastics and other recovered carbon;
- biogenic carbon dioxide from processes such as biogas upgrading and fermentation; and
- captured carbon dioxide combined with low-emission hydrogen.
Biomethane cannot directly replace every product obtained from an oil refinery. Its simple methane molecule must first be converted into useful chemical intermediates. For example, biomethane can be reformed into synthesis gas and subsequently converted into methanol. Methanol is an important platform chemical from which fuels, solvents, resins and other chemical products can be manufactured.
Because the carbon in biomethane comes from recently living biological material rather than a newly extracted fossil reserve, these pathways can help reduce the chemical industry’s dependence on virgin fossil carbon. Their actual climate performance still depends on sustainable feedstocks, processing energy, methane-slip control, carbon efficiency and what happens to the finished product at the end of its life.
This may become one of biomethane’s most strategically valuable roles. Sustainable biomethane will always be limited, and many straightforward heating applications can increasingly be electrified. Carbon-based chemicals and materials, by contrast, cannot be manufactured without a carbon source.
Future resource planning should therefore ask not only:
“How much fossil gas can this biomethane replace as a fuel?”
It should also ask:
“Should this renewable carbon be preserved for chemicals and materials that society cannot produce using electricity alone?”
The European Commission recognises that the chemicals sector will continue to require carbon feedstock and identifies sustainably sourced biomass as one alternative to fossil carbon. Its bioeconomy strategy likewise includes bio-based chemicals, plastics, fibres and other materials among the important routes for reducing dependence on oil, natural gas and coal.
- European Commission: The Facts About the Bioeconomy
- European Commission: Bio-based Products and Processes
Why Is Biomethane Renewable?
Biomethane is classified as renewable because its carbon originates from organic material that forms within the contemporary biological carbon cycle rather than from a finite geological fossil reserve.
That does not mean every unit of biomethane is automatically carbon-neutral. But it is always less of a climate changer than natural gas.
A proper environmental assessment must be conducted for the AD facility and consider:
- how the feedstock was produced;
- what would have happened to it without anaerobic digestion;
- transport and processing energy;
- land-use effects;
- methane leakage from the digester, upgrading plant and digestate storage;
- the management and use of digestate; and
- which fossil fuel or activity the biomethane replaces.
Combusting biomethane releases carbon dioxide, just as burning fossil natural gas does. The distinction is that most of this carbon was recently absorbed during biological growth. Nevertheless, methane unintentionally escaping (known as a fugitive methane emission) before combustion is a powerful greenhouse-gas emission and can substantially weaken the lifecycle benefit.
Is Biomethane Good for the Climate?
Well-managed biomethane made from suitable wastes and residues can deliver significant greenhouse-gas reductions compared with fossil natural gas. Its benefits may be particularly strong where anaerobic digestion captures methane that would otherwise have escaped from manure or organic waste.
However, the result is not identical for every plant or feedstock.
The International Energy Agency reports that measured methane emissions from current biogas and biomethane plants can amount to approximately 2% to 5.5% of their output. It therefore identifies closed digestate storage, treatment of upgrading off-gases, good process control and leak detection and repair as essential practices.
A peer-reviewed investigation of 69 Danish biogas plants found enormous variation between individual sites. The production-weighted national methane-loss figure was 2.5%, but individual results ranged from 0.3% to 40.6%. Measurements at six plants following corrective work found that relatively minor fixes and adjustments reduced their combined emissions by 46%.
The lesson is straightforward: biomethane’s climate credentials depend on measuring and controlling methane throughout the plant.
For a detailed examination of this issue, read Fugitive Emissions Testing: A Complete Biogas Industry UK Guide.
What Are the Main Benefits of Biomethane?
- It can replace fossil natural gas. Properly conditioned biomethane can serve many existing gas applications.
- It is storable. Unlike weather-dependent generation, gas can be stored and used according to demand.
- It can use existing infrastructure. Suitable gas networks, storage facilities and appliances may continue to provide value during decarbonisation.
- It recovers energy from organic wastes. Food waste, manure and sewage sludge can become feedstocks rather than simply disposal problems.
- It can support local energy production. Feedstocks and gas can often be sourced and processed regionally.
- It can help manage methane-producing wastes. Controlled digestion can capture gas that might otherwise escape during uncontrolled decomposition.
- It produces digestate. Appropriately managed digestate can return nutrients and organic matter to land.
- It can support difficult decarbonisation applications. Renewable gas may be valuable where direct electrification is impractical or disproportionately expensive.
- It can act as a transitional technology for heavy transport, an area that lacks the high energy density fuel not yet fully provided by batteries, while hydrogen cell technology becomes mainstream
For more detail see: Biomethane plant advantages.
What Are the Limitations of Biomethane?
Biomethane is useful, but it is not an unlimited replacement for all fossil gas consumption.
- Sustainable feedstocks are limited. Organic wastes and residues have many competing uses and are geographically dispersed.
- Upgrading requires energy and equipment. The process adds capital cost and consumes some of the energy being produced.
- Methane leakage and methane slip can undermine the benefit. Digesters, pressure-relief systems, pipework and digestate stores can release methane through leaks and operational emissions. During biogas upgrading, some methane may also remain in the separated carbon-dioxide-rich off-gas rather than entering the biomethane product stream. This is known as methane slip. Unless the methane is recovered, recycled or destroyed—for example, in an off-gas treatment system—it may be released into the atmosphere and materially weaken the lifecycle climate benefit.
- Feedstock choices matter. Poorly chosen energy crops can create land-use, biodiversity and food-production concerns.
- Combustion still produces emissions. Biomethane is not a zero-emission fuel at the point of use.
- Gas quality must be controlled. Grid injection and vehicle use require reliable cleaning, monitoring and safety systems.
- Digestate needs responsible management. Nutrient losses, ammonia emissions and water pollution can occur if it is stored or applied badly.
Biomethane should therefore be directed towards applications where it provides a strong overall environmental and practical advantage, rather than being treated as justification for unlimited continued gas consumption.
Biomethane in the UK and Europe
Biomethane now forms part of both energy-security and decarbonisation policy.
The European Union has established an objective of reaching 35 billion cubic metres of annual sustainable biomethane production by 2030. The European Commission sees biomethane as a storable renewable gas that can use existing infrastructure while reducing dependence on imported fossil gas.
In Great Britain, Ofgem administers the Green Gas Support Scheme, which supports eligible biomethane produced by anaerobic digestion and injected into the gas grid. Participants must meet lifecycle greenhouse-gas and feedstock sustainability requirements.
These requirements are important because calling a gas “renewable” does not, by itself, demonstrate that every production route is sustainable.
The Future Role of Biomethane
The strongest case for biomethane is not that it can replace every unit of fossil natural gas. Available sustainable feedstock is unlikely to support such an outcome.
Its value lies in combining several functions:
- managing unavoidable organic wastes;
- capturing methane that might otherwise escape;
- producing controllable renewable energy;
- using established gas infrastructure selectively;
- supporting industrial and transport applications that are difficult to electrify; and
- recycling nutrients through properly managed digestate.
The IEA estimates that less than 5% of the world’s potential sustainable biogas and biomethane feedstock is currently being used. It also stresses that expansion must be accompanied by much stronger methane management.
Biomethane is therefore neither a universal answer nor a technology that should be dismissed because it is chemically methane. It is a practical renewable-gas option whose value depends on the feedstock, the engineering, the methane-loss rate and the fossil activity it replaces.
Frequently Asked Questions About Biomethane
What is biomethane in simple terms?
Biomethane is purified biogas. Most carbon dioxide, water and unwanted trace compounds are removed from raw biogas, leaving a gas composed predominantly of methane.
What is the difference between biogas and biomethane?
Biogas is the raw gas produced by anaerobic digestion and contains substantial carbon dioxide as well as methane. Biomethane is biogas that has been upgraded to increase its methane concentration and make it suitable for higher-value uses.
Is biomethane the same as natural gas?
The principal methane molecule is the same, but the sources differ. Biomethane comes from biological material or organic waste, while conventional natural gas is extracted from fossil geological deposits.
Is biomethane carbon-neutral?
It should not automatically be described as carbon-neutral. Its lifecycle impact depends on feedstocks, processing energy, methane leakage, land use, digestate management and the fuel or activity it replaces.
Can biomethane be used in an ordinary gas boiler?
Biomethane that has been conditioned to the applicable gas-network standard can be blended into the grid and used by compatible gas appliances in the same way as the surrounding gas supply.
What does RNG mean?
RNG means renewable natural gas. The term is widely used in North America for upgraded biogas or biomethane that can substitute for conventional natural gas.
Can biomethane be made from manure?
Yes. Livestock manure and slurry are common anaerobic-digestion feedstocks. Capturing and using their methane can provide climate benefits when the plant controls leakage and manages the remaining digestate responsibly.
Does biomethane produce carbon dioxide?
Yes. Burning biomethane produces carbon dioxide. Most of that carbon is biogenic rather than fossil, but the complete lifecycle must still be assessed when calculating its greenhouse-gas impact.
Research and Authoritative Sources
- International Energy Agency: Outlook for Biogas and Biomethane
- European Commission: Biomethane
- US Environmental Protection Agency: Renewable Natural Gas from AD and Biogas Systems
- Ofgem: Green Gas Support Scheme Guidance
- Fredenslund et al.: The Danish National Effort to Minimise Methane Emissions from Biogas Plants
[Published January 2021. Rewritten September 2026.]
Biogas and biomethane are already available and they are also cost-competitive, if we consider all positive externalities generated by the production of these renewable gases. Europe is the largest producer of biogas and biomethane in the world today, and it will be essential to scale up production of these renewable gases in order to meet renewable energy demand by 2030 and achieve climate targets in 2050.