Assessment of waste derived gases as a renewable energy source – Part 1

UK government requires local authorities to develop Municipal Waste Management Strategies, to put in place policies to reduce greenhouse gas emissions and contribute to meeting both the EU Landfill Directive and UK government recycling targets.To assist the decision making process, a study was commissioned to compare the energy produced by treating 100,000 tpa residual municipal solid waste to provide a fuel derived from treating the waste using anaerobic digestion (AD) and gasification technologies used on-site, with the equivalent off-site use. Comparison of technology scenarios was based on a number of parameters, comprising efficiency of energy production, energy capacity, avoided CO2e1 emissions and capital and operating costs.The study examined a total of 41 technology combinations that produce/use waste-derived gases based on gasification and AD, against a base case of on-site power production only. Scenarios considered for using the gases derived included on/off-site use in CHP units based on gas engines and fuel cells and use as a transport fuel for vehicles. The relative performance of on/off site options was influenced by a trade-off between a reduction in efficiency caused by supply chain losses and parasitic requirements that tend to favour on-site options and improvements in efficiency achieved by delivering a greater quantity of recovered heat to end users.Part 1 of the two part paper sets out the background to the study, assumptions made and methodology used and describes the 41 technology combinations assessed. In Part 2 the outputs generated by the assessment process are presented and discussed.