Energy from Waste
Energy from Waste (EfW) is a term describing the technologies used to recover energy from the burnable fraction of waste, which rather than going to landfill can be combusted in an incineration plant with energy, and potentially heat, recovery. All EfW plants have a boiler to capture and convert the released heat, and an extensive air pollution control system that cleans the combustion gases to comply with regulatory emission limits before they are released to atmosphere through the stack. The recovered electricity can be fed into the national grid, and recovered steam exported to adjacent industrial premises or townships for space heating, hot water supply, and other duties. Plants that recover both heat and electricity are called Combined Heat and Power (CHP) plants.
Whereas in countries such as Sweden and Denmark some 40 % of the community and domestic requirement comes from district heating schemes linked to EfW/CHP plants, this type of application has yet to find widespread use in the UK.
The development of EfW could play a role in helping the UK to meet its international obligations to reduce the emission of greenhouse gases, in particular carbon dioxide, by replacing fossil fuels as a source of energy. For this reason EfW generated heat and electricity are exempt from the Climate Change levy. Currently, 210 MW of electricity is generated in 15 EfW plants in the UK incinerating 3.3 million tonnes of municipal waste. In 2002, 3% of electricity generated in the UK was sourced from renewables, of which 23% was derived from EfW.
There are three key issues in the debate about EfW as a waste management option in the UK:
- Whether EfW acts as a disincentive to materials recovery and recycling, ie displacing the preferred waste management options higher up the waste hierarchy
- Whether incineration is a safe process, or whether it poses a risk to public health
- Whether EfW is economically and environmentally viable
The economic viability of energy from waste depends to some degree on its eligibility as a "renewable energy source" in the Government's Renewables Obligation (RO) scheme. Currently mixed waste incineration is not eligible for inclusion under the Renewables Obligation scheme. A review of the scheme, and the eligibiltiy of energy from mixed wastes, was carried out in 2005/06 and some interim papers have been released but the final decisions are yet to be announced.
Environmental questions have been raised in a recent report commissioned by Friends of the Earth. In the report, 'A Changing Climate for Energy from Waste' produced by Eunomia Research & Consulting and available for download from the link below, the report states that although waste incineration is seen as green energy as it can displace electricity produced from coal-fired incineration, its greenhouse gas emissions are actually higher (around 33 % higher at 500g of CO2 per KWh of electricity compared to < 400g for a gas-fired station) than those from gas-fired power stations (although emissions are still much less than with coal-fired [800g of CO2 per KWh of electricity] or oil-fired power stations [770g of CO2 per KWh of electricity). The report questions the true efficacy of waste incineration and puts forward the case for greater use of aerobic digestion to deal with waste diverted from landfill, and greater development of technology to improve the efficiencies of waste incineration before new plants are built.
Energy from Waste in the North East
Currently, there is only one Energy from Waste plant operating in the North East. This is the Teesside Energy from Waste plant run by SITA Tees Valley Ltd, a joint venture between SITA UK and the four Teesside local authorities of Stockton, Middlesborough, Redcar & Cleveland, and Hartlepool. A flyer about this plant can be downloaded below.
Some facts and figures about the plant:
- The plant is one of the newest in the UK and has been fully operational since May 1998.
- It operates 24 hours a day, 7 days a week, processing municipal and non-hazardous industrial & commercial waste.
- It receives up to 4,000 tonnes of municipal waste every week.
- It produces an average of 20 megawatts of electricity per hour.
- It generates enough electricity to supply 40,000 homes with power.
- It has generated over 856,000 megawatt hours of electricity since opening (to August 2004).
In October 2005, Entec was commissioned by Government Office for the North East to conduct a study into the number, type and location of residual waste treatments planned for the North East to quantify the shortfall in provision of treatment capacity and its geographical distribution and to establish baseline data on the availability of waste material for energy recovery and facilities for the conversion of waste to energy.
The report looked at the schedule of current and planned facilities for the conversion of waste materials to energy, an estimate of the medium and long-term future arisings of waste material suitable for generating electricity, with its geographical distribution and an estimate of the potential production and availability of RDF (refuse derived fuel) out of waste currently being landfilled.
The report estimated that potentially around 800,000 tonnes of RDF could be produced in the region, which is sufficient to generate enough electricity to meet 5 % of the region's electricity demand. This is some 450,000 tones greater than current capacity can handle, so it would require significant new infrastructure to be developed. Also the report found that there are currently few markets for RDF and any new build would need to have contracts in place in order to secure financial backing. Also public acceptance was low and the industry would need to win over public support for any new Energy from Waste plant build programme. A copy of the report is available for download below
