RECOVERING VALUE FROM WASTE
Value can be recovered from waste which cannot be recycled or composted by using it to generate energy, heat and to collect residual materials for recycling.

Energy-from-waste (EfW) is the recovery of renewable energy in the form of electricity and/or heat from the controlled incineration of residual waste. Every municipal EfW plant in the UK recovers value from the waste treated. All twenty facilities recover energy while a number also recover heat, metals and other materials which can be safely recycled and used in construction.

In 2005/06 2.8 million tonnes (8%) of municipal waste was treated in EfW facilities in the UK. [1] The Government’s Waste Strategy for England 2007 anticipates that EfW activity will increase in the future, estimating that it will account for 25% of municipal waste treatment in England by 2020.

In 2006, EfW generated the equivalent of 776,000 tonnes of oil [2] - generating enough power for over ¼ million homes. Recovering energy from waste displaces emissions that would otherwise be emitted by fossil fuel power stations and helps increase the UK ’s own security of fuel supply. Waste Strategy for England 2007 [3] states that “Recovering energy from waste which cannot sensibly be recycled is an essential component of a well-balanced energy policy.”

Across Europe EfW is considered to be a valid alternative to landfill for dealing with waste. Countries such as Denmark and Switzerland , which have achieved far higher recycling rates than the UK , also rely much more heavily on EfW.

EfW plants operate to the highest design specifications and emissions are stringently monitored for compliance with European Union standards by the Environment Agency in England and Wales , and SEPA in Scotland . Emission control standards are reviewed regularly, and the Waste Incineration Directive [4] has set stricter standards to be met by all plants since 2005.

Energy from waste facilities in the UK
Twenty EfW facilities currently operate in the UK (18 in England and two in Scotland ). The capacity of the individual facilities ranges from 26,000 tpa [5] at Lerwick to 530,000 tpa at Edmonton in London , and together have a total capacity of 4.3 million tpa.  

Several facilities are Combined Heat and Power (CHP) plants and supply heat - as well as electricity - to homes and businesses. CHP schemes increase the efficiency of a power generation plant, although the viability of a CHP scheme is dependent on the availability of an end-user for the heat.

Generation of renewable electricity
The electricity generated from the biogenic fraction of waste accounts for a third of all the UK ’s renewable energy generating capacity. According to official figures from BERR [6], of the 4.6% of electricity from renewable sources utilised in the UK in 2006, 30% was derived from waste management companies:

·           24% was generated from landfill gas (4,424 GigaWatt hours)

·           6% from incinerating the biodegradable fraction of MSW (1,083 GigaWatt hours)

Renewable energy is also generated from the incineration of wood wastes, farm waste digestion, poultry litter combustion and meat and bone combustion.

Recovery and recycling of materials
Many EfW facilities in the UK now incorporate recycling plants which recover recyclable materials and send residual waste for energy recovery. Ferrous and non-ferrous metals are further recovered from the ash following energy recovery.

Incinerator bottom ash (IBA), which constitutes approximately 25% by weight of the input waste, is used as a substitute for natural aggregate. Recycling IBA displaces the use of non-renewable virgin materials and reduces the impacts of extraction. Approximately 900,000 tonnes of IBA is produced each year and over a half is recycled as secondary aggregate for roadbase material, asphalt and concrete building blocks.

Emissions
Emissions to the atmosphere from EfW facilities are closely monitored by the Environment Agency and SEPA. The Waste Incineration Directive, which applies to all energy from waste facilities, sets stringent emission controls and when introduced resulted in significant reductions in emissions from EfW facilities treating MSW.

According to the UK Health Protection Agency [7], the incineration of MSW accounts for less than 1% of UK emissions of dioxins, and are significantly less than the amount of dioxins released into the atmosphere on bonfire night or from accidental fires. The combined emissions of nitrous oxides (NOx), sulphur dioxide (SO2), particulate matter (PM10) and volatile organic carbon (VOC) from the all of the UK ’s EfW facilities are significantly lower than that emitted by transport and other major industries.

Environment and health effects
In 2004, DEFRA published a report, “Review of Environmental and Health Effects of Waste Management: Municipal Solid Waste and Similar Wastes” [8]. Peer reviewed by the Royal Society, the report concluded that risks to human health from incineration are small in comparison with other known risks and that there was no evidence for a link between the incidence of disease and the current generation of incinerators. In addition, the role of incineration with energy recovery was acknowledged as a sustainable waste management option.

April 2008

[1]http://www.defra.gov.uk/environment/statistics/waste/kf/wrkf20.htm

[2]http://stats.berr.gov.uk/energystats/dukes07_c7.pdf

[3]http://www.defra.gov.uk/environment/waste/strategy/

[4]http://ec.europa.eu/environment/air/stationary.htm#2

[5]tonnes per annum

[6]http://stats.berr.gov.uk/energystats/dukes7_4.xls

[7]http://www.hpa.org.uk/chemicals/ippc/incineration_posn_statement.pdf

[8]http://www.defra.gov.uk/environment/waste/research/health/