Potential for manure-based anaerobic digestion

Motivations, barriers and approaches in six countries

This report by Task 37 (Energy from Biogas) examines the motivations, barriers, and approaches for utilizing manure through anaerobic digestion (AD) in Canada, China, Finland, France, Norway, and the United Kingdom, all IEA Bioenergy TCP member countries.

Globally, manure is an abundant and easily convertible feedstock for renewable energy, stable organic matter, and nutrients via anaerobic digestionAD. Despite its great potential, currently only a small percentage of manure is converted into biogas and/or biomethane. These countries, spread across three continents, share many of the same motivations, such as renewable energy production, direct and indirect greenhouse gas reduction, sustainable animal production, prevention of water and air pollution, soil carbon and nutrient management, circularity, and farm income diversification. For example, Finland focuses on biomethane for heavy transport to achieve carbon neutrality, while China uses AD for environmental solutions in the expansion of animal production.

Download the full report: “Potential for manure-based anaerobic digestion”

Policies, regulations, and financial incentives are crucial factors for the adoption of manure-based AD. Unlike the municipal waste and wastewater sector, where anaerobic digrestion systems are considered public infrastructure, in the agricultural sector, the individual producer typically raises the capital and operates the anaerobic digestion system, requiring a profitable business case. All six countries have policies to encourage anaerobic digestion, either directly through recommendations for manure treatment (China), grants and operating incentives (China, Finland, France, Norway), or indirectly through premiums for renewable energy (Canada, UK). The trend has shifted from combined heat and power (CHP) to biomethane production, which poses challenges for smaller installations not located near natural gas pipelines. However, there is resistance to continuous public support, with policymakers desiring a decline in biomethane costs.

Key barriers include high capital and operating costs, few revenue streams, and low energy prices, which hinder profitability. Other barriers include the low methane potential of manure (compared to, for example, food waste), the need for co-digestion with other, more energy-rich substrates, challenges with infrastructure and logistics (dispersed farm locations, distance to gas networks), complex approval processes and community resistance, as well as a lack of expertise and standardized technologies.

To address these challenges, various approaches are taken:

• Co-digestion: Manure is often combined with other organic materials such as food waste, crop residues, or intermediate crops to increase methane potential and achieve economies of scale.
• Larger, centralized anaerobic digestion systems: Many countries are developing larger, centralized facilities, often located near an accessible natural gas network, to realize economies of scale. This leads to a shift from individual farmer ownership to ownership by agricultural cooperatives or third parties.
• Innovative logistics: In countries like Finland and Norway, biomethane is compressed or liquefied and transported by truck to users or fueling stations.
• Knowledge sharing and training: There is a continuous need for knowledge sharing, operator training, and ongoing education to ensure the efficient operation of anaerobic digestion facilities.

The report emphasize the vast, untapped potential of manure-based anaerobic digestion to contribute to renewable energy production, greenhouse gas reduction, water resource protection, and nutrient recycling in a circular economy. However, further adoption requires targeted policy support and recognition of the multifaceted benefits that anaerobic digestion systems can provide.

Take-aways for Policymakers

Anaerobic digestion of manure represents an untapped potential for greenhouse gas emission reduction and energy security:

The report highlights that manure is a huge, yet currently underutilized resource for biogas production, which is crucial for achieving climate goals. Anaerobic digestion of manure can significantly reduce methane emissions—a potent greenhouse gas—from agriculture and replace fossil fuels, directly contributing to climate mitigation. Furthermore, it offers the opportunity to increase the energy self-sufficiency of countries and farms, strengthening energy security in a time of volatile energy prices. Policymakers should recognize this potential and develop strategies to mobilize this resource, given the urgent need for both carbon reduction and diversified energy sources.

Multifunctional benefits exists for sustainable agriculture and the circular economy, Beyond Energy Production Alone:

The report clearly states that manure-based anaerobic digestion offers much more than just renewable energy; it provides essential services for air and water quality protection, soil health improvement, and the promotion of a circular economy. The digestates (co-products of anaerobic digestion) are rich organic fertilizers that reduce the need for synthetic fertilizers, build soil carbon, and optimize nutrient cycles. These ecological and agronomic benefits are often not explicitly financially recognized or compensated, forming a significant barrier to adoption. For policymakers, it is crucial to value these broad societal contributions and embed them in policy instruments, so that investments in manure-based AD are not only judged on energy sales but on the total value it creates for the environment, agriculture, and the economy.

Download the summary report “Potential for manure-based anaerobic digestion”

Overview of Jiangsu Xinyi Animal Manure Treatment and Valorisation Project.