What is the EU Taxonomy?
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What is biogas and is it sustainable?
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As the world looks for alternatives to fossil fuels, biogas has gained attention as a solution that transforms organic waste into usable energy. It sounds like a win-win – but does it hold up under scrutiny, and how sustainable is it really?
Biogas production relies on anaerobic digestion, a natural process where bacteria break down organic materials like food waste, manure, and sewage to produce a methane-rich gas. This gas can be burned for heat and electricity or refined into biomethane, a fuel that can replace natural gas. Unlike fossil fuels, biogas is considered carbon-neutral because the carbon released during combustion was originally absorbed by plants during photosynthesis. However, its sustainability depends on various factors, including how it’s produced, transported, and used.
So, is biogas a real climate solution, or does it have hidden drawbacks? In this article, we'll explore what biogas is, its environmental impact, and whether it truly lives up to its reputation as a sustainable energy source.
What is biogas?
“Biogas is a type of biofuel produced when organic matter decomposes in an oxygen-free environment, a process known as anaerobic digestion.”
The resulting gas is primarily composed of:
- Methane (CH₄) – Typically 50-75%, making biogas highly combustible.
- Carbon dioxide (CO₂) – Around 25-50%, the main non-combustible component.
- Other trace gases – These include hydrogen sulfide (H₂S), nitrogen (N₂), and small amounts of water vapor.
Because of its high methane content, biogas can be burned to generate electricity, heat, or even refined into biomethane, which has the same properties as natural gas.
How is biogas produced?
Biogas is created through anaerobic digestion, a natural process where bacteria break down organic materials in an oxygen-free environment. This occurs in biogas digesters (or anaerobic digesters), which are sealed tanks designed to optimise methane production. The process follows three key steps:
- Hydrolysis: Complex organic materials (like carbohydrates, proteins, and fats) break down into simpler molecules.
- Acidogenesis and acetogenesis: Microbes convert these molecules into fatty acids, alcohols, hydrogen, and CO₂.
- Methanogenesis: Methanogenic bacteria transform these compounds into methane-rich biogas.
Common feedstocks for biogas production
The type of organic material used as feedstock plays a major role in the efficiency and sustainability of biogas production. Common feedstocks include:
| Waste Type | Description |
|---|---|
| Agricultural waste | Crop residues, manure, and plant waste. |
| Food waste | Household and industrial food scraps, supermarket waste, and expired products. |
| Sewage sludge | Biogas is often extracted from wastewater treatment plants. |
| Landfill waste | Organic waste in landfills naturally decomposes and releases biogas, which can be captured and used. |
“Biogas is often promoted as a circular solution since it makes use of organic waste that would otherwise break down in landfills, releasing methane directly into the atmosphere. But does that make it sustainable? That depends on how it’s produced, used, and scaled - something we’ll explore in the following sections.”
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Applications of biogas
Biogas is a versatile energy source with a range of applications. From electricity generation to transportation, its uses extend beyond simply burning gas. But how exactly is biogas utilised, and how does it compare to conventional fossil fuels?
| Application | Description |
|---|---|
| Electricity and heat generation | Used in combined heat and power (CHP) plants to generate both electricity and heat. Biogas is combusted, converted to electricity, and waste heat is repurposed. Common in farms, wastewater treatment plants, and food processing facilities. |
| Upgrading biogas to biomethane | Raw biogas is purified to remove CO₂ and contaminants, producing biomethane. Upgraded biomethane can be injected into gas grids or used as vehicle fuel, reducing reliance on fossil fuels in transport. |
| Industrial and residential uses | Used in industrial manufacturing, residential heating and cooking, and micro-scale digesters for farms, hotels, and households. Provides a flexible, scalable energy source. |
Electricity and heat generation
One of the most common applications of biogas is in combined heat and power (CHP) plants, where it is burned to generate both electricity and heat. This process follows a simple principle:
- Biogas is combusted in a gas engine or turbine.
- The energy is converted into electricity, which can be used locally or fed into the grid.
- The waste heat is captured and repurposed for heating buildings, water, or industrial processes.
Because of this dual-purpose efficiency, biogas CHP systems are particularly useful for farms, wastewater treatment plants, and food processing facilities, where organic waste is readily available. These systems help reduce reliance on fossil fuels while making use of materials that would otherwise go to waste.
Upgrading biogas to biomethane
Raw biogas isn’t always suitable for direct use in pipelines or vehicles as it contains impurities like carbon dioxide and hydrogen sulfide. To make it functionally equivalent to natural gas, biogas can be upgraded to biomethane through a process called purification or scrubbing, which removes CO₂ and contaminants.
Once upgraded, biomethane can be:
- Injected into natural gas grids, allowing homes and businesses to use it just like conventional gas.
- Used as vehicle fuel, replacing diesel and petrol in buses, trucks, and even passenger cars.
Several countries, including Sweden and Germany, have already integrated biomethane into their transport sectors, promoting it as a cleaner alternative to fossil fuels. Since it produces fewer pollutants and carbon emissions than petrol or diesel, it’s often considered an important tool for decarbonising transportation.
Industrial and residential uses
Beyond power plants and transport, biogas can also be used:
- In industrial manufacturing, where it replaces fossil fuels in high-temperature processes.
- For residential heating and cooking, especially in rural areas where natural gas infrastructure is lacking.
- In micro-scale digesters, which allow farms, hotels, and households to generate their own energy from organic waste.
These applications make biogas a flexible and scalable energy source, but its impact depends on how widely it’s adopted, and whether it can truly reduce emissions in the long run.
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Environmental impact of biogas
Biogas is often positioned as a green alternative to fossil fuels, but how does it really impact the environment?
While biogas offers clear benefits, such as reducing waste and lowering methane emissions, it’s not without its drawbacks. Let’s take a closer look at its role in cutting greenhouse gas emissions, its resource efficiency, and the potential environmental concerns that come with its production.
Greenhouse gas emissions: how does biogas compare?
One of the biggest advantages of biogas is its ability to capture methane that would otherwise escape into the atmosphere. Methane is a potent greenhouse gas - more than 25 times stronger than CO₂ over a 100-year period. By collecting and burning it in a controlled way, biogas projects prevent uncontrolled methane release from landfills, wastewater, and agricultural waste.
“However, burning biogas still releases CO2. The difference is that this carbon comes from recently grown organic materials rather than long-buried fossil fuels. In theory, this makes biogas carbon-neutral, but only if methane leaks are kept under control.”
A key issue is that biogas infrastructure, like digesters and gas storage systems, can leak methane. If these leaks aren’t properly managed, biogas could undermine its own climate benefits.
Reducing waste and closing the loop
Biogas is often praised for its role in the circular economy. Instead of organic waste decomposing in landfills or being incinerated, biogas systems repurpose it into energy. This helps:
- Reduce landfill methane emissions, which contribute significantly to climate change.
- Lower reliance on fossil fuels, replacing coal, oil, or natural gas in energy production.
- Produce digestate - a nutrient-rich byproduct that can be used as fertiliser in agriculture.
This waste-to-energy approach is a major environmental advantage, but it’s not perfect. Some large-scale biogas operations grow crops specifically for biogas production, rather than using waste materials. This can lead to concerns over land use, deforestation, and competition with food production.
Potential environmental drawbacks
While biogas has clear benefits, it’s not free from criticism. Some of the main environmental concerns include:
| Issue | Description |
|---|---|
| Methane leaks | If not properly managed, leaks from biogas facilities can offset its climate benefits. |
| Air pollution | Burning biogas produces nitrogen oxides (NOx), which contribute to smog and respiratory issues. |
| Water contamination | Poorly managed digestate (the solid byproduct of biogas production) can lead to water pollution if it’s over-applied or improperly stored. |
| Land use concerns | Some biogas operations rely on energy crops (like maize and soy) instead of organic waste, raising concerns about deforestation and food security. |
“These challenges highlight the fact that not all biogas is equally sustainable. The way it is produced and used makes a huge difference. So, while biogas has the potential to be a cleaner alternative to fossil fuels, its environmental benefits depend on proper regulation, technology, and responsible sourcing.”
Economic and social considerations
Beyond its environmental impact, biogas also has economic and social implications. On the surface, it seems like a win-win - turning waste into energy while creating jobs and reducing reliance on fossil fuels. But does it make financial sense? And how does it impact communities?
Is biogas economically viable?
The cost-effectiveness of biogas depends on several factors, including production scale, feedstock availability, and government incentives. While it has lower long-term fuel costs compared to fossil fuels, the initial investment in biogas plants can be high. Key economic factors include:
- Upfront costs: Building anaerobic digesters, gas purification systems, and infrastructure requires significant investment.
- Operational expenses: Maintenance, monitoring, and feedstock collection add to ongoing costs.
- Government subsidies and incentives: Many countries offer financial support, such as feed-in tariffs, tax credits, and grants for biogas projects.
- Revenue streams: Biogas plants can generate income from electricity sales, biomethane supply, carbon credits, and digestate (used as fertiliser).
In regions with strong policy support, biogas can be highly profitable. For example, in Germany and Sweden, government-backed biogas programs have made biomethane a viable alternative to natural gas. However, in countries with low fossil fuel prices and weak incentives, biogas struggles to compete economically.
Job creation and rural development
One of the biggest social benefits of biogas is its potential to create jobs and support rural communities. Since biogas production often relies on agricultural waste and food industry byproducts, it can provide new income opportunities for farmers and waste management businesses.
- New jobs in waste collection, plant operation, and maintenance
- Revenue for farmers supplying manure or crop residues
- Local energy production, reducing dependence on imported fuels
In developing countries, small-scale biogas systems can improve energy access, particularly in off-grid rural areas. These systems provide clean cooking fuel, reducing reliance on firewood and charcoal, which contribute to deforestation and indoor air pollution.
Challenges in scaling biogas
While biogas has clear social and economic benefits, scaling up production comes with challenges:
- Competing with cheap fossil fuels: Without subsidies, biogas struggles to match the low cost of natural gas in many countries.
- Infrastructure limitations: Many regions lack the pipelines and facilities needed to distribute and store biomethane.
- Feedstock sourcing issues: If demand for biogas grows too quickly, producers may turn to energy crops, raising concerns about land use and food security.
Ultimately, biogas is most successful in regions where governments actively support its development - either through subsidies, mandates, or carbon pricing schemes.
Biogas in the UK, US, and EU
Biogas is a component in the renewable energy strategies of the United Kingdom (UK), the United States (US), and the European Union (EU). Each region has tailored its approach to biogas production and utilisation, reflecting unique policy frameworks, technological advancements, and market dynamics:
United Kingdom (UK)
The UK has committed to integrating biogas into its energy mix, driven by ambitious climate goals and supportive policies.
- Policy initiatives: In August 2023, the UK government published its Biomass Strategy, outlining the role of biomass, including biogas, in achieving net-zero emissions by 2050. This strategy emphasises investment in domestic energy production, job creation, and supply chain development across the nation.
- Industry developments: In February 2025, AstraZeneca inaugurated a biomethane plant in Lincolnshire, designed to generate biogas from organic waste. This facility is expected to supply 100 gigawatt-hours of renewable energy annually, powering the company's UK research and manufacturing sites and accounting for 20% of the company’s global gas consumption.
- Local initiatives: Nottingham-based start-up Dark Green plans to establish a series of plants across urban centers to convert food waste into green energy. Each facility aims to process 60,000 tonnes of organic waste annually, reducing carbon emissions equivalent to removing 65,000 cars from the road and generating energy sufficient to power approximately 6,000 homes.
European Union (EU)
The EU has positioned biogas as a cornerstone of its strategy to enhance energy security and achieve climate neutrality.
- Production growth: In 2023, biogas production in Europe reached 234 terawatt-hours, covering 6.6% of the EU's natural gas demand. This marks a significant increase, with an installed capacity of 6.4 billion cubic meters (bcm) of biomethane per year.
- Policy framework: The REPowerEU plan, launched in response to geopolitical tensions, aims to boost the EU's biomethane production to 35 billion cubic meters annually by 2030. This initiative seeks to diversify energy sources and reduce dependence on fossil fuel imports.
- Member state initiatives: France and Italy have led the charge in expanding biomethane production. This surge is attributed to supportive policies and significant investments in biogas infrastructure.
United States
The US biogas industry has expanded rapidly, driven by increased investments, policy support, and a shift toward Renewable Natural Gas (RNG).
- Industry growth: As of 2025, the US has 2,478 operational biogas sites, spanning agriculture, wastewater treatment, and landfills. Investment in new biogas systems grew by $3 billion in 2024, reflecting a 40% increase from the previous year.
- Agricultural expansion: Farm-based biogas projects saw an 18% growth, rising from 522 to 615 sites, as the sector embraced anaerobic digestion to manage livestock waste and generate energy.
- Policy and market trends: Federal and state incentives, including tax credits and carbon credit programs, continue to drive growth. California's Low Carbon Fuel Standard (LCFS) has strengthened demand for biogas as a transportation fuel.
- Shift to RNG: 95% of new biogas projects in 2024 were designed to upgrade raw biogas into RNG for use in pipelines and vehicles. This reflects the industry's push toward integrating biogas into existing natural gas networks.
The future of biogas
Biogas has emerged as a crucial player in the global shift toward renewable energy, but its future will depend on technological advancements, policy support, and sustainability improvements. While it offers a low-carbon alternative to fossil fuels and a solution for organic waste management, scaling biogas sustainably remains a challenge.
Opportunities for growth:
| Trend | Description |
|---|---|
| Technological innovation | Advancements in methane capture, purification, and efficiency could enhance biogas's climate benefits while reducing leaks. Emerging solutions like electrochemical CO₂ conversion may also improve carbon capture from biogas plants. |
| Policy and market expansion | With global governments tightening carbon reduction targets, biogas could benefit from increased subsidies, carbon pricing, and stricter regulations on landfill emissions. In regions like the EU and California, policy-driven demand for Renewable Natural Gas (RNG) is expected to grow. |
| Integration with other renewables | Biogas can complement wind and solar by providing dispatchable energy - meaning it can generate power on demand, helping balance intermittent renewables in the energy grid. |
Challenges to overcome:
| Challenge | Description |
|---|---|
| Sustainability concerns | Large-scale biogas production must prioritise waste-based feedstocks rather than relying on energy crops, which can compete with food production and contribute to deforestation. |
| Economic viability | Without continued policy incentives, biogas struggles to compete with cheaper renewables like wind and solar. Long-term cost reductions will be essential for widespread adoption. |
| Infrastructure and scaling issues | Upgrading and transporting biogas to national grids or industrial users requires significant investment in pipelines, refining facilities, and distribution networks. |
Is biogas the future?
“Biogas isn’t a silver bullet for the climate crisis, but it remains a valuable tool in the transition to a low-carbon economy - particularly as a waste-to-energy solution. When sourced responsibly and paired with emissions reduction strategies, it can cut methane emissions, replace fossil fuels, and support circular economies. However, its long-term sustainability depends on limiting methane leaks, improving efficiency, and ensuring that biogas complements rather than delays the transition to truly renewable energy sources.”
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How Greenly can help your company
At Greenly, we help businesses navigate the complexities of carbon management and emissions reduction. Our suite of carbon management services includes:
- Carbon footprint assessments: We provide detailed emissions tracking, helping companies understand the impact of their Source 1, 2, and 3 emissions.
- Lifecycle analysis: Our team evaluates the full environmental impact of products, from production through to end-of-life disposal.
- Net-zero strategy development: While biogas can contribute to emission reductions, it’s not a standalone solution. We help businesses create customised and effective decarbonisation pathways.
- Regulatory compliance: With evolving climate policies in the UK, US, and EU, we guide businesses through reporting requirements and sustainability regulations.
Talk to our team today and start making data-driven decisions for a lower-carbon future.
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