What is an energy-from-waste plant?
An energy-from-waste (EfW) plant (formerly called an incinerator or waste-to-energy facility) is an industrial installation that burns non-recyclable residual waste and converts the released heat into electricity and/or district heating. The UK has around 50 operational EfW plants.
How does an EfW plant work?
The process follows these steps:
- Delivery — residual waste is delivered by lorry and stored in a bunker
- Combustion — the waste is burned at approximately 850–1,100 °C on a moving grate
- Heat recovery — the hot flue gases heat water into steam in a boiler
- Energy generation — the steam drives a turbine that generates electricity
- Flue-gas cleaning — the gases are cleaned of harmful substances
- Residual products — bottom ash (incinerator bottom ash aggregate, IBAA) is processed for reuse as a construction material
Applications
- Bottom ash as aggregate — processed IBAA is used as fill material in road foundations and earthworks
- District heating — many EfW plants supply residual heat to local heat networks
- Circular economy — metals are recovered from the ash for recycling
- Construction sector — construction and demolition waste makes up a significant proportion of the waste stream processed by EfW plants
Related terms
- Sustainable construction
- District heating
- Circular economy
- Waste water
- Recycled aggregate
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