Technical Report

Identification and assessment of sustainability effects associated with biogas solutions

Literature review and perspectives from five countries

March 2025

Summary

A societal sustainability transition is urgent, requiring the shift towards a more circular and regenerative biobased economy. Biogas solutions (based on anaerobic digestion, AD) can take many different forms, from sludge stabilization at wastewater treatment plants to stand-alone digestion of the organic material separated from municipal waste to digestion of dairy manure and intermediate crops in rural areas to landfill gas collection, and can produce a number of energy and digester/biofertilizer products, and biogenic carbon dioxide. Biogas solutions are multifunctional and can deliver key products and services to society, such as energy, mobility, nutrients, fodder, clean water, chemicals, and environmental services including sustainable management of natural resources. Across the globe, there is great potential for expanded adoption of biogas solutions.

BROAD RANGE OF SUSTAINABILITY EFFECTS

Based on a scientific literature review this report describes the roles of biogas solutions in different parts of society, identifying the sustainability effects observed through five lenses: 1) biogas solutions adopted in the waste and wastewater treatment sector; 2) biogas solutions adopted in agriculture/rural areas; 3) the use of digestate/biofertilizer; 4) the use of biogas energy, biomethane and biogenic carbon dioxide (CO2); and 5) society at large. In total, 53 sustainability effects are presented in detail, including information on critical factors and relevant references. While greenhouse gas (GHG) emission reduction is one positive effect that is seen repeatedly, some sustainability effects are unique to a particular lens. For example, biogas solutions for wastewater treatment provide important societal services such as sanitation and improved water quality, while in the agriculture sector they can diversify farm income and encourage new production practices for more resilient agriculture. The majority of the sustainability effects are positive, reinforcing the message that biogas solutions offer multiple benefits to society – in addition to renewable energy and GHG emission reduction. However, the other effects are often not well documented and can be difficult to quantify, leading them to be undervalued or even absent from decision-making. A few effects are negative and should be avoided or mitigated, as for any operation. Also, it was noted that some effects can be positive or negative depending on the operation of the biogas plant or the context, and care should be taken to adopt good operating procedures along the entire value chain.

COMPREHENSIVE ASSESSMENTS FOR BETTER DECISIONS

Today, new development of biogas solutions is strongly based on its energy and GHG emissions reduction value while the other sustainability effects are not given very much consideration. The report includes several examples of comprehensive sustainability assessments that use systems analysis methods such as multi-criteria assessment (MCA) to evaluate multiple effects of biogas solutions and thereby carry out more complete comparisons. Two transport sector MCA studies from Sweden bring to light the strengths and weaknesses of different energy carriers, and provide insights on the best applications of biomethane in transport. In addition, the report reviews studies completed in France, Switzerland and for Europe (EU 27 and UK) that have identified key sustainability effects of biogas solutions, including the main beneficiaries, and monetized some of the effects (or externalities). They all consider biogas systems to provide several products and numerous positive effects that benefit society at large. As such the total added value makes biogas solutions highly competitive from a socio-economic perspective, when compared to both nonrenewable and other renewable alternatives, and helps to justify the government support that governments provide to the sector. Such comprehensive studies provide a more complete understanding of all of the attributes of biogas solutions and point to the different types of organizations (or actors) that should be involved in value chain development and decision-making.

EXPERIENCES FROM FIVE MEMBER COUNTRIES

Experiences regarding biogas systems and associated sustainability effects are shared by experts from five Task 37 Member Countries – Canada, France, Norway, Sweden and Switzerland. In each of these countries, biogas solutions have evolved over several decades, influenced by factors such as population density, the industrial and agricultural profiles, energy resources and infrastructure, geography and climate. From the technology perspective, the solutions are very similar to one another as wet, organic wastes and residues from the municipal, industrial and agricultural sectors are converted into biogas energy (electricity, heat and biomethane) and digestate/biofertilizer meeting quality standards is applied to agricultural soils according to site specific prescriptions. As such these five countries acknowledge many of the same sustainability effects, but the relevance of the effects (or the order of importance) varies among countries depending on the types of biogas solutions and feedstocks, the energy end-uses of the biogas, and the country’s goals with respect to waste management, environmental protection, climate change and its clean energy transition.

For each country, descriptions are provided of the country contexts and biogas systems, relevant sustainability effects, important drivers and barriers related to these systems and effects, and outlooks for further adoption. Some of the interesting features include Switzerland’s strong adoption of biogas solutions for wastewater treatment with almost complete coverage, Canada’s attention on landfill gas capture and treatment in its methane reduction strategy, France’s significant use of intermediate crops as a co-substrate with manure in its many agricultural biogas plants, and Norway and Sweden starting to digest fish processing sludge to lower the risks of eutrophication. All countries have digestate standards and guidelines in place to recover the nutrients for crop production and reduce synthetic fertilizer use, while protecting their soils and water supplies. The respective contributions of biogas energy to the country’s energy mix and GHG emission reduction depend to a large extent on the country’s energy infrastructure, its energy and transport policies, and how biogas energy is recognized in its clean energy transition.

At a societal level, biogas solutions appear to be in good alignment with the countries’ commitments to sustainable development, including goals on climate change mitigation; waste management; regenerative, circular bioeconomy; and more recently, the broader concept of supply security, including not only energy but also food/nutrients, water, and biogenic carbon. While many sustainability effects are cross-sectoral and benefit society at large, all five countries note the essential roles that public policies, legislation and financial support continue to play with respect to advancing biogas solutions. A mix of influential policy related drivers and barriers exist in the studied countries. Policy related risks and uncertainties influence the development of biogas solutions, and its competitiveness is strongly influenced by policy, including subsidies for competing and complementary alternatives. A strong focus on electrification and future hydrogen systems presents a serious challenge to new development.

GUIDANCE FOR PLANNERS, DEVELOPERS AND THE POLICY COMMUNITY

The opportunities for biogas solutions are expected to increase as populations and their associated waste generation continue to grow, and land and resources become more limited. While energy systems become more decarbonized, the value of the other sustainability effects of biogas solutions, such as resource recovery and circularity, could increase over time. However, many pieces have to fall into place to build reliable, efficient value chains, and both local communities and the broader public have to be willing to accept biogas solutions and their respective roles in supporting development.

It is of utmost importance that decision-makers, including planners, developers and policymakers, and the public develop a comprehensive understanding of the broad system effects of biogas solutions and their highly cross-sectoral nature involving waste management, energy, industry and agriculture. Unlike mono-functional systems which are easier to understand and manage, biogas solutions contribute to multiple sectors and sustainability goals, and require a great deal of crosssectoral collaboration to create industrial-urban-rural symbiosis.

The report concludes by proposing the following recommendations:

Promote More Holistic Understanding and Perspectives

• Use science-based, multi-criteria sustainability assessments to inform decisions on technical alternatives.
• Recognize the cross-sectoral benefits of biogas solutions in waste, wastewater, agriculture, energy, transport, and various industrial sectors.
• Encourage greater cross-sector collaboration, shared decision-making and support solutions that contribute to a circular economy. Include different sized solutions and solutions that are co-created with local communities.
• Shift the focus toward integrated strategies that combine multiple renewable technologies to deliver desired functions while addressing urgent sustainability challenges.

Adopt Coherent and Effective Policy Frameworks

• Harmonize lifecycle and value chain perspectives across relevant policies.
• Enable biogas value chain actors to capture the full societal value of their contributions.
• Remove regulatory and administrative barriers, such as restrictions on sustainable crop-based biogas and lengthy approval processes for mature technologies.
• Set clear targets for the production and use of biogas, biomethane, digestate/biofertilizers, and biogenic CO₂, and ensure the development of supporting infrastructure and access to land to make these targets achievable.
• Balance top-down strategies with local adaptability to facilitate effective and implementation.

Executive summary