Waste-to-Energy is integral to reach the landfilling reduction target for municipal solid waste, besides being a source of energy which can contribute towards the achievement of renewable energy targets while providing a reliable electricity and heat supply.
Waste-to-Energy (WtE) refers to the recovery of energy from waste, such as municipal solid waste (MSW), which allows for the production of electricity and heat.
Different types of WtE technologies exist. These include among others (i) incineration with energy recovery, (ii) waste gasification, (iii) and waste pyrolysis. The most present in Europe of these technologies is that of incineration with energy recovery. This might be attributable in part to its flexibility in handling the various waste fractions making up MSW, while the latter two require a relatively homogeneous waste stream, such as wood waste, agricultural residues, sewage sludge, and plastic waste.
A main operational difference between these technologies is that while incineration is based on the direct combustion of waste in the presence of oxygen, waste gasification is based instead on the partial oxidation of waste in the presence of a controlled amount of oxygen, and waste pyrolysis is based on the thermal degradation of waste in absence of oxygen.
Furthermore, from an energy recovery perspective, the end products of these three technologies are also different. While incineration with energy recovery produces steam for electricity and/or heat, waste gasification produces synthetic gas and waste pyrolysis produces liquid fuel; both synthetic gas and liquid fuel can be stored, thus can be flexibly used for further combustion or employed in other sectors (source: UNEP report on Waste-to-Energy).
While energy recovery is one of its many benefits, WtE is mainly applied with the aim of preventing the landfilling of waste when this is no longer re-usable or recyclable, as indicated by the Waste Framework Directive. Avoiding the landfilling of MSW, (a phenomenon still widespread in several EU countries as illustrated in this fact sheet by ESWET), means preventing the decomposition of the organic fraction of MSW under anaerobic conditions, typically occurring in landfills. This, in turn, prevents the release of methane gas, a potent greenhouse gas.
Furthermore, by preventing landfilling WtE prevents the formation of leachate, which otherwise can contaminate underground water reservoirs. Additionally, thermal recovery of waste comes with the added benefit of hygienisation and volume reduction of waste (50-90% reduction depending on the technology and waste feedstock - source: UNEP report on Waste-to-Energy).
Through the concept of Clean Energy Hubs, Energy Technologies Europe fully supports the integration of WtE into the EU energy mix as a tool to promote both a sound waste management system and to decarbonise the economy. Energy Technologies Europe advocates for an adequate policy framework that recognises these important contributions to the environment.