Mobilising sustainable supply chains - biogas cases : biogas production from municipal solid waste, oil palm residues and co-digest

Agricultural and industrial biomass residues are promising feedstocks, but their availability for energy production, the available conversion methods and the organisation of production chains are all subject to debate. Anaerobic Digestion (AD) is a process of degradation of organic material by microorganisms under anaerobic conditions. Feedstocks include biodegradable residues including food wastes, sewage, and animal residues, while biomass from dedicated crops can be used to enhance biogas yields. A co-digestion or co-fermentation plant is typically an agricultural anaerobic digester that accepts two or more input materials for simultaneous digestion. Advantages of AD include its flexibility in processing both dry and liquid feedstocks, including manure and municipal sludge, as well as the fact that it is already fully developed at household, farm and industrial scales, and provides an effective upgrade of residues. It is also a clean and safe alternative to fossil fuels. AD has a very favourable energy output to input ratio, and high potential to diminish Greenhouse Gas (GHG) emissions. Methane can be stored, while the byproduct (digestate) is a valuable source of nutrients and organic matter. Potential disadvantages of AD include the risk of explosion, gas toxicity (caused by hydrogen sulphide), and unpleasant odours, while the risk of methane leakages reduces the potential GHG benefits. IEA Bioenergy aims to stimulate a substantial bioenergy contribution to future energy demand. Accelerating production and use of environmentally sound, socially acceptable and costcompetitive bioenergy will help to provide increased security of supply, while reducing emissions from energy use. This report is part of a broader IEA Bioenergy InterTask Project ‘Mobilising sustainable bioenergy supply chains’. It discusses: biogas production from organic residues, biogas production from the organic fraction of Municipal Solid Waste (MSW), use of oil palm residues, and co-digestion of agricultural residues (manure and substrates)...