What is waste-to-energy?

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Waste-to-energy (WtE) involves technologies that transform waste into usable energy through thermal processes, primarily incineration. It is recognized as a regulated waste management approach, alongside landfilling and recycling.

The most prevalent form of waste-to-energy is the incineration of municipal solid waste (MSW) to produce electricity. Around 13% of the world's municipal waste is processed in WtE facilities as feedstock.1 MSW consists of solid waste materials—including food scraps, product packaging, discarded clothing, old furniture, and yard trimmings—originating from homes, businesses, and public institutions.

Waste-to-energy offers a potential solution to the increasing global waste challenge by significantly decreasing the amount of waste destined for landfills. Additionally, it often results in lower greenhouse gas emissions compared to alternative waste management strategies.

While WtE serves as an alternative to energy generation from fossil fuels, it does not qualify as a renewable energy source, as it relies on waste rather than naturally replenishing resources like wind or sunlight. Moreover, WtE is not entirely clean, since both the incineration of waste and the transportation involved in the process release carbon emissions and other airborne pollutants.

How does waste-to-energy work?

Most large-scale WtE facilities rely on controlled incineration to convert waste into energy. The process generally involves the following stages:

Waste is delivered to the facility, where any recyclable materials are first removed.

An overhead crane mixes the remaining waste and feeds it into the combustion chamber.

The waste is then incinerated at extremely high temperatures, typically ranging from 850°C to 1,450°C (1,562°F to 2,642°F).²

The intense heat generated by combustion is used to boil water, often circulating in pipes within the chamber walls, transforming it into high-pressure steam.

This pressurized steam is directed at the blades of a turbine generator, causing it to spin and ultimately produce electricity.

The amount of energy recovered depends on the composition of the waste. Materials with a high calorific value, such as various plastics, burn hotter and yield more energy. Conversely, organic materials like food scraps or garden waste have a much lower calorific value and contribute less to energy generation.