Energy from Waste via combustion
(also known as Waste to Energy)
This technology has a long track record and is very widely used. There are over 430 plants operating in Europe, and in excess of 20 fully commercial scale plants operating in the UK.
Modern facilities are fundamentally different from previous generation mass burn waste 'incinerators' which had minimal, if any, air emission control systems, and did not recover any of the energy released during the combustion process. The old incineration facilities of the 1980’s would not meet today’s stringent regulatory standards prescribed by European legislation and monitored by the Environment Agency.
Many old plants were closed down in the 1990's, although some underwent very substantial redesign to allow them to meet modern emission and operational requirements.
Facilities rely on combustion to release the energy stored in residual waste. Main advantages include:
- Long track record, proven to work with mixed complex wastes
- Possible to develop on various scales including large facilities
- A record of being economically viable
- Used to generate heat and electricity and increasingly cooling
- Metals and the remaining bottom ash can be recycled
How it works?
Waste is transferred to an enclosed bunker and then fed into a combustion chamber via a hopper and combusted under controlled conditions at a high temperature. The resulting gases are cleaned prior to monitoring and release via a stack.
Heat produced during combustion is used to drive a steam turbine which generates electricity for export to the grid. Hot water and steam can also be exported for heat use in local houses and industry or can be converted for cooling through heat exchangers.
The facility will produce two main types of residue – Incinerator Bottom Ash (IBA) and Air Pollution Control (APC) residues. Recyclable metals are removed from the IBA for recycling and the remaining is commonly processed into an aggregate for use in civil engineering applications. The quantity of APC residues produced is much lower, usually about 2-3% of the waste that is processed. APC residues are hazardous waste, primarily because they are highly alkaline. APC residues are typically transported from the site in sealed containers and disposed of or recovered at a specially licenced facility. > FAQ 11
Modern EfW facilities must meet strict emission limits set by the European Union under the Waste Incineration Directive. Controls on emissions from these facilities are tighter than other large industrial plants such as coal-fired power stations.
All EfW facilities must have an Environmental Permit issued by the Environment Agency in order to operate. A strict monitoring regime is maintained as part of the permit, with emissions data regularly published and available to the public.
Process and Technology
> See how an EfW combustion plant works