Europe’s farms could play a bigger role in the continent’s transition to renewable energy, with livestock manure, crop residues and other agricultural by-products offering potential feedstocks for biomethane production.
Produced by upgrading biogas, biomethane is a renewable gas that can be used in many of the same applications as conventional natural gas, including heating, industrial processes and transport. Agricultural waste could help expand production while creating additional value from materials generated by farming.
However, turning that potential into a reliable energy supply will require more than building additional digestion plants. Feedstock availability, collection costs, competing uses of agricultural residues and the environmental consequences of removing organic material from farmland will all influence how much biomethane Europe can sustainably produce.
The opportunity is significant, but its scale will depend on how effectively the energy sector and agriculture industry work together to develop a supply chain that delivers environmental benefits alongside commercially viable production.
Which agricultural by-products can produce biomethane?
Agricultural feedstocks are not a single resource. They include several types of material, each with different characteristics, methane yields and practical challenges.
Livestock manure
Manure from cattle, pigs and other livestock is an important potential feedstock for anaerobic digestion. In a controlled environment, microorganisms break down its organic matter in the absence of oxygen, producing biogas that can subsequently be upgraded into biomethane.
One advantage of manure is that it is already generated as part of normal agricultural activity. Using it for biogas production can help farms recover energy from an existing waste stream rather than relying exclusively on crops grown specifically for fuel.
There can also be an important climate benefit. Manure management can release methane when organic material decomposes without controlled capture. Anaerobic digestion can capture some of this methane for energy, but the overall benefit depends on how the manure would otherwise be managed and whether emissions are controlled throughout production.
However, manure is bulky and contains substantial moisture, making transportation expensive. Smaller farms may struggle to justify the cost of an individual digestion plant, particularly where livestock numbers are limited, or no nearby facility can process their material.
This makes local and cooperative approaches potentially valuable. Several farms could supply a shared facility, spreading investment and operating costs across a larger feedstock base.
Crop residues and agricultural by-products
Crop residues offer another source of material for biomethane production. These include straw, cereal husks, maise cobs and other plant material left over after harvesting or processing.
Unlike dedicated energy crops, residues are generated alongside food production. Using suitable portions of this material can therefore provide an additional resource without necessarily requiring more agricultural land.
However, not all crop residues are surplus to requirements. Straw and other organic material can help maintain soil organic matter, support soil structure and reduce erosion. Some residues are also used for animal bedding, livestock feed or other agricultural purposes.
Removing too much material could undermine these functions, potentially creating environmental costs that outweigh the benefits of additional renewable gas.
The challenge is to identify the fraction that can be collected sustainably, taking account of soil conditions, farming practices and existing uses. Residues also differ in their composition and ease of processing, meaning that pretreatment may be required to make some materials more suitable for anaerobic digestion.
Cover crops and other organic materials
Cover crops and sequential crops, grown between main cropping periods or alongside existing rotations, can also feature in some biomethane production systems.
Their suitability depends on how they are grown, harvested and incorporated into farming practices. Any additional crop production must be assessed against its effects on land use, water demand, soil health and biodiversity.
The wider principle is that biomethane expansion should prioritise genuinely sustainable feedstocks rather than assume that all available biomass is environmentally beneficial when converted into fuel.
The International Energy Agency’s assessment of sustainable biogas and biomethane feedstocks distinguishes between materials such as manure, crop residues and biowaste, while considering whether their use would compete with food production, animal feed or other important purposes.
How agricultural waste becomes biomethane
The production process begins with anaerobic digestion. Organic material is fed into a sealed tank, where microorganisms break it down in the absence of oxygen. The resulting biogas contains methane and carbon dioxide, alongside smaller quantities of other gases and impurities.
Biogas can be used directly in suitable equipment to generate heat and electricity. To produce biomethane, however, it must undergo an upgrading process that removes most of the carbon dioxide and reduces unwanted impurities to meet the required gas-quality specifications.
The resulting gas can then be injected into a compatible gas network or used in applications requiring a higher methane concentration, depending on the infrastructure available.
This distinction matters because increasing biogas production does not automatically translate into an equivalent increase in grid-ready biomethane. Upgrading equipment, gas connections, storage and appropriate distribution infrastructure may all be needed.
Digestate, the material remaining after digestion, is another important part of the process. It can retain nutrients and may be used as an organic fertiliser, subject to its composition, quality and applicable requirements. Returning suitable digestate to farmland can help recycle nutrients, although it still needs to be managed carefully to avoid pollution.
For agricultural producers, the potential value therefore extends beyond the gas itself. A well-designed system could combine renewable energy production with waste management and nutrient recycling.
Europe’s biomethane ambitions face a feedstock challenge
The European Union has identified biomethane as a potential contributor to energy security and decarbonisation, with agricultural waste expected to play a role in expanding production.
Under the REPowerEU plan, the EU established an ambition to reach 35 billion cubic metres of sustainable annual biomethane production by 2030. However, the European Commission reported that EU biomethane production stood at approximately 3.93 billion cubic metres in 2024, illustrating the scale of the expansion required.
National ambitions are also uneven. Member states differ in their agricultural resources, existing digestion infrastructure, financial support mechanisms and ability to connect new production facilities to the gas network.
Agricultural waste biomethane could help bridge part of this gap, but feedstock availability alone will not determine how quickly production can grow. Projects also need to secure long-term supplies of suitable organic material, obtain planning permission, finance construction and establish a viable route to market.
The International Energy Agency’s 2025 analysis of biogas and biomethane highlights the importance of feedstock composition, plant size and location in determining production costs. Manure can be expensive to transport because of its high moisture content, while areas with concentrated supplies of crop residues may be better suited to larger facilities.
These differences mean that there is no single model for expanding agricultural biomethane across Europe. Some regions may benefit from individual farm digesters, while others could support centralised facilities supplied by multiple farms.
The economics of turning agricultural waste into energy
For farmers, the decision to supply agricultural residues or invest in anaerobic digestion will depend on the financial returns and the risks involved.
Building and operating a digestion plant requires capital, technical expertise and reliable feedstock supplies. Biomethane production adds further costs because the gas must be upgraded to the required quality before it can enter a gas network or be used in certain applications.
Smaller farms may find these investments difficult to justify independently. Cooperative arrangements could offer a way forward, allowing farmers to share the cost of facilities and equipment while securing a more consistent supply of feedstock.
However, transporting organic material over long distances can erode the economic benefits. This is particularly relevant for manure, which is bulky and relatively dilute. Locating facilities close to farms and available feedstocks can therefore be important for keeping costs manageable.
Revenue from biomethane sales is another consideration. Projects need sufficient certainty over future prices, policy incentives and demand to justify long-term investment. Grid connection costs and delays can also affect whether a proposed facility becomes operational.
Digestate may provide an additional source of value if it can be used safely and economically as a fertiliser. Yet its commercial value depends on nutrient content, local demand, transport requirements and the cost of storage and application.
The economics are therefore highly site-specific. A project that works in a livestock-dense region with nearby gas infrastructure may not be viable in an area with dispersed farms, limited feedstock supplies or expensive grid connections.
Protecting soil health while expanding production
One of the central questions surrounding agricultural waste biomethane is how to increase production without creating new environmental problems.
Crop residues have several important functions beyond their potential use as an energy feedstock. Leaving suitable residues on fields can help protect the soil from erosion, maintain organic matter, support soil biodiversity and improve water retention.
Removing too much material can undermine these benefits. The sustainable quantity available for energy production therefore varies according to soil type, climate, crop rotation and existing farming practices.
The same principle applies to other agricultural materials. Feedstocks may already have valuable uses as animal bedding, feed, compost or soil amendments. Diverting them into energy production could create competition between different uses rather than simply making productive use of waste.
Anaerobic digestion also needs to be assessed across its full lifecycle. Methane leakage, energy consumption, transportation and digestate management can all affect the environmental performance of a project.
This does not negate the potential benefits of biomethane. It means that expansion should focus on feedstocks and production methods that deliver genuine emissions reductions while protecting the wider agricultural system.
The European Commission has emphasised the importance of developing biomethane from sustainable waste and residues, rather than encouraging feedstocks that could compete with food and feed production or contribute to harmful land-use changes.
Can agricultural waste help close Europe’s biomethane gap?
Agriculture could make a meaningful contribution to Europe’s renewable gas ambitions, particularly where farms can supply suitable organic residues and manure to efficiently operated digestion facilities.
The opportunity extends beyond energy production. Properly managed systems can capture methane from manure, provide an additional revenue stream for farmers and return nutrients to agricultural land through digestate.
But agricultural waste should not be treated as an unlimited resource. Its availability is constrained by competing uses, collection costs, seasonal variations and the need to maintain healthy soils. Technical potential must also be distinguished from the amount that can realistically be collected and processed at a competitive cost.
Progress will depend on matching production technologies to local conditions, supporting collaboration between farms, improving access to finance and ensuring that suitable infrastructure is available to distribute the resulting gas.
For policymakers, the priority is to encourage sustainable production rather than pursue output targets at any cost. For farmers and developers, success will depend on whether projects can deliver reliable financial returns alongside demonstrable environmental benefits.
Agricultural waste biomethane is unlikely to meet Europe’s energy needs on its own. Nevertheless, making better use of suitable agricultural by-products could help diversify gas supplies, reduce avoidable emissions and strengthen links between farming and renewable energy.