Trends and drivers in alternative thermal conversion of waste

IEA bioenergy Task 36 “Material and energy valorisation of waste in a circular economy” prepared this report about trends in waste management for the example of municipal solid waste (MSW). Within the waste hierarchy, recycling is given preference over recovery, and waste-to-energy (WtE) conversion is given preference over landfilling. MSW is non-hazardous household and commercial waste, of which more than one third typically is biogenic in origin. Incineration represents the state-of-the-art WtE technology; alternative thermal treatment technologies such as gasification and pyrolysis have had far fewer applications to MSW due to economic factors and relatively low technology readiness. This is a situation that is currently changing. Specifically in the European Union (EU) technologies develop and new pathways are sought. Major trends in the EU are driven by legislation and implementation goals, some of which are country specific: • banning of landfilling in combination with limited social acceptance and, in some countries, legal restrictions for additional incineration capacity • increasing waste generated or imported in combination with limited incineration capacities have led to increased waste treatment cost (gate fees) and waste exports • recycling rates that are lower than EU and national Circular Economy objectives • global demand for sustainable routes for waste processing, particularly with regards to reducing greenhouse gas (GHG) emissions, and • heightened social awareness and concerns about environmental impacts including climate change and marine littering. Key opportunities driven by these trends are related to the adoption of non-incineration thermal technologies • for energy recovery as a response to decreasing public acceptance for direct waste incineration, and • as a pathway to chemical recycling of waste, which accelerates the transition to a Circular Economy. This involves co-processing of biomass and waste to improve the economies of scale associated with biomass conversion plants. The upcoming report discusses both trends impacting solid waste management systems within EU countries as well as selected alternative thermal treatment technologies. Aspects concerning technology readiness and affordability are highlighted in this report as well as the need to combine mechanical waste pretreatment and sorting with thermochemical treatment in order to increase recycling rates and to improve economics.