Sustainable supply potential and costs – Outlook for biogas and biomethane: Prospects for organic growth – Analysis – IEA
This report uses a new IEA estimate of the sustainable technical potential of biogas and biomethane supply, based on a detailed assessment of the availability of 19 types of feedstocks across the 25 regions modelled in the World Energy Model. The assessment used detailed cost, feedstock and technology data to derive supply cost curves illustrating the potential scale and commercial viability of different biogas and biomethane production pathways around the world. This section considers first the potential and costs for biogas, followed by those for biomethane.
For biogas, this report considered 17 individual types of residue or waste, grouped into the four feedstock categories described in Section I, namely crop residues, animal manure, the organic fraction of MSW and wastewater sludge. Biogas production pathways vary by feedstock and region and rely on the following main technologies: biodigesters (including centralised digesters at small, medium or large scale and decentralised digesters at household scale), landfill gas recovery systems, and wastewater treatment municipal plants.
For biomethane this report considered two main production pathways: upgrading biogas and the gasification of biomass. For biogas upgrading, the same feedstocks assessed for biogas have been considered, on the assumption that these can be used either for biogas production or for upgrading biogas to biomethane. The alternative route to biomethane production – gasification – opens up the possibility of using two additional sources of solid biomass feedstock: forestry residues and wood processing residues.
This analysis focuses primarily on the opportunities and costs of biogas and biomethane, thereby excluding technologies to convert electricity to gas (also known as power-to-gas) and methanation using the CO2 extracted during the biogas upgrading process.
As noted in Section I, this analysis includes only the technical potential of feedstock that can broadly be considered sustainable. This is defined as feedstocks that can be processed with existing technologies, which do not compete with food for agricultural land and that do not have any other adverse sustainability impacts (e.g. reducing biodiversity). Although energy crop residues are included, energy crop feedstocks grown specifically to produce biogas and biomethane are not included on the basis that their sustainability warrants further in-depth analysis outside the scope of this study.
The estimates of the sustainable technical potential of biogas and biomethane evolve over time, and are affected by gross domestic product (GDP) and population growth, urbanisation trends, changes in waste management, and anticipated rates of technology evolution.
This report’s assessment of supply costs matches feedstock availability with the appropriate production technologies, and draws on a number of case studies of the unit costs of biogas and biomethane production around the world. The costs presented here differ slightly from those in the World Energy Outlook 2019 (IEA, 2019b). This is mainly due to the adoption of a more comprehensive data set for biogas upgrading technologies, separate consideration of the costs of connecting upgrading facilities to the gas grid, and inclusion of the latest published data and information.
