Waste-to-Energy plants burn household and similar waste that remains after waste prevention and recycling.
From this waste the plants generate energy. This can be in the form of steam, electricity or hot water. The electricity is fed into the grid and distributed to the end-users, the hot water, depending on local infrastructure can be sent to a nearby district heating (or cooling) network to heat (or cool) homes, hospitals, offices etc., and the steam can be used by the nearby industry in their production processes.
Waste-to-Energy is a hygienic method of treating waste, reducing its volume by about 90%.
In a Waste-to-Energy plant apart from the waste itself no additional fuel is needed to maintain the combustion process. Additional fuel is only used for the start up and shut down phases.
Modern Waste-to-Energy plants are clean and safe, meeting the most strict emission limit values placed on any industry set out in the European Waste Incineration Directive
Waste-to-Energy fulfils a number of different yet important roles:
Firstly it helps reach the targets set in the EU Landfill Directive that aims to reduce the amount of biodegradable waste being landfilled. The deadline for reducing landfilling by 50% was in July 2009and European Member States that miss these targets face hefty fines.
By treating household and similar waste that remains after waste prevention and recycling Waste-to-Energy plants help avoid the methane, a very potent greenhouse gas (GHG), that would have been created if the waste was landfilled.
Waste-to-Energy and Recycling are complementary waste treatment methods. Household and similar waste should be sorted at source and the clean materials should be sent to high quality recycling. The remaining waste, that cannot be recycled in a technically or economically viable way, should be used to generate energy. In order to divert waste from landfill both Recycling and Waste-to-Energy should be part of a “joined up thinking” approach to sustainable waste management.
The energy produced in Waste-to-Energy plants also contributes to climate protection and security of energy supply, by replacing fossil fuels that would have been used to produce this energy in conventional power plants.
A significant part of the waste treated in Waste-to-Energy plants is biogenic – biomass – which means that about half of the energy produced by Waste-to-Energy plants is renewable energy. This is also the case when bio-waste is separated at source, as there is still a significant amount of biogenic waste which is too polluted for high quality composting.
Member States who landfilled more than 80% of their municipal waste in 1995 could apply for derogation on the application of the Landfill Directive by up to 4 years: Bulgaria, Czech Republic, Estonia, Ireland Latvia, Lithuania, Poland, Romania, Slovakia and the United Kingdom. For these Member States the deadlines are 50% by 2013 and 65% by 2020.
The Waste-to-Energy industry has made huge strides over the last 20 years to reduce emissions. This progress has been further driven by the introduction of the European Waste Incineration Directive (WID) in 2000, which sets the stringent emission limit values that plants now achieve. It is worth noting that these emission limits are the strictest placed on any industry.
We would like to put peoples’ minds at rest that it is safe to live near Waste-to-Energy plants and that they have little or no impact on the health of their neighbours. Rather than us telling you, please follow this [link] for a list of studies by eminent scientists and national environment agencies and ministries from across Europe. They all confirm that it is safe to live near a modern, well run Waste-to-Energy plant operating Best Available Techniques.
The best way to learn about having a Waste-to-Energy plant as a neighbour is to ask somebody who lives near one. The next best thing is to visit one yourself. Many plants offer open door days – please contact us for more information email@example.com.
One famous example of a Waste-to-Energy plant is in the centre of Vienna – called Spittelau. This plant is so well known as a landmark in the city that it attracts tourists from around the world in its own right. The Spittelau plant provides the nearby hospital with heating and cooling.
Municipal waste – household and similar waste, such as office waste – is made up of many different substances, which often contains pollutants. When these materials are burnt in Waste-to-Energy plants they are released from the waste in a controlled way.
The flue-gas cleaning system is one of the most important parts of a Waste-to-Energy plant, as it enables the plant to guarantee the very low emissions that are achieved today. It is a complex set of chemical reactions which aim to neutralize and minimize the emissions.
The residues from the flue gas cleaning system are captured using advanced and proven technology, and different Waste-to-Energy plants have different designs to clean the flue-gases.
During the combustion process hot flue gases are released in the furnace and their heat is transferred to water inside the boiler tubes which produces steam for energy generation.
The gases then enter the flue gas cleaning system, and are cleaned in a number of stages:
Please follow this link to an animation on how a Waste-to-Energy plant works [link]
The flue gas cleaning system represents a significant part of a plant and it accounts for up to 50% of the construction costs of a Waste-to-Energy plant.
The emissions are very closely monitored in every Waste-to-Energy plant and centralized in the control room. A number of plants even have this information live on their web-site so that neighbours living close to the plant can see that the emissions are as low as possible [link to live emissions data from the ISVAG Waste-to-Energy plant in Belgium].
Perhaps a surprising fact about modern Waste-to-Energy plants is that what can be seen coming out of the chimney at the end of the process is mostly water vapour.
The residual waste treated in Waste-to-Energy plants is burned under controlled conditions, reducing the volume of the waste by about 90%.
In a Waste-to-Energy plant the bottom ash is collected at the end of the furnace’s grate. It consists of non-combustible materials, and is the residual part from the incineration of waste. Even if the waste was sorted before hand, there are metals found in it. Both ferrous metals and non-ferrous metals can be taken out of the bottom ash and recycled. After the metals are taken out, the rest of the ashes, which are like gravel or sand, are stored for a period before being used in road construction or as a covering layer on landfill sites.
A paper by CEWEP on the "Environmentally sound use of bottom ash" can be downloaded from below.
The residues from the flue gas cleaning system amount only to 3-4 % of the mass of the waste entering the plant. These residues are collected after the filtration process and must be carefully stored to ensure no escape of the material into the local environment. The material is then transported in sealed containers to hazardous landfill sites, to treatment plants or salt mines. These sites must be fully contained so that the material cannot leach out into the environment.
By thermally treating household and similar waste that remains after waste prevention and recycling in an efficient Waste-to-Energy plant, they reduce both methane emissions (a potent greenhouse gas 25 times more significant in mass to global warming than carbon dioxide CO2) from landfilling and CO2 emissions that would have been produced if the amount of energy was generated in conventional power plants.
The Intergovernmental Panel on Climate Change(IPCC) says that “GHG generation can be largely avoided through controlled aerobic composting and thermal processes such as incineration for waste-to-energy.” And “Compared to landfilling, waste incineration and other thermal processes avoid most GHG generation, resulting only in minor emissions of CO2 from fossil C sources.”
Considering the benefits of the avoided GHG emissions from landfills and conventional power plants, and taking into account the credits for metal recycling from bottom ash, from a Life Cycle perspective Waste-to-Energy performs well with regard to GHG emissions.
Waste-to-Energy technology is one of the most robust and effective alternative energy options to reduce CO2 emissions and to save limited fossil fuel resources used by traditional power plants.
Currently, Waste-to-Energy Plants in Europe can supply 13 million inhabitants with electricity and 13 million inhabitants with heat. This is based on 73 million tonnes of remaining household and similar waste that was treated in 2010 in Europe.
Depending on the fuel you replace – gas, oil, hard coal or lignite – between 7 – 40 million tonnes of fossil fuels emitting 20 – 40 million tonnes of CO2, would not need to be used by conventional power plants to produce this amount of energy.
According to EU legislation the biodegradable fraction of municipal and industrial waste is considered biomass, thus a renewable energy source [Link to the EU RES Directive]. The energy output from Waste-to-Energy plants is about 50% renewable.
Waste-to-Energy plants in Europe supply a considerable amount of renewable energy, some 38 billion kilowatt-hours in 2006, and by 2020 this amount will grow to at least 67 billion kilowatt-hours, but potentially reach 98 billion kilowatt-hours. This will be, in the latter case, enough to supply 22.9 million inhabitants with renewable electricity and 12.1 million inhabitants with renewable heat. However, to achieve the latter, a more ambitious waste policy must be delivered in Europe, i.e. replacing landfilling through a combination of recycling (60%) and Waste-to-Energy (40%), as well as increasing energy efficiency through improved infrastructure for heating and cooling, and better grid access for energy from Waste-to-Energy plants.
If unpretreated waste is not landfilled anymore and recycling, as well as efficient energy recovery (Waste-to-Energy), is increased, then around 114 million tonnes CO2 equivalents could be avoided by 2020 in EU-27 [Study by ifeu/Öko-Institut on behalf of UBA/BMU/BDE, „Klimaschutzpotentiale der Abfallwirtschaft“, January 2010]. This calculation is based on household and similar waste, but if commercial waste is taken into account then the amount of avoided CO2 equivalents would be even higher.
In order to move away from Europe’s high dependence on fossil fuels we should explore the cost-effective and available sustainable energy option: Waste-to-Energy.
Waste-to-Energy has a positive influence on recycling rates. It is well known that the European Member States that have the highest rates of recycling also include Waste-to-Energy as an integral part of their waste management systems, and have lower rates of landfilling. Consequently, Member States with lower rates of recycling tend to have less Waste-to-Energy treatment and higher rates of landfilling. Please follow this [link] to a graph based on data from EUROSTAT (European Statistical office) where this can be seen.
As much waste as possible should be recycled. However, the quality of the sorted waste going to recycling should be such so that no dirty or polluted waste re-enters the new recycled material. The remaining waste which cannot be recycled in an environmentally or economically feasible way should be sent to Waste-to-Energy plants where its energy content can be used.
Even the most progressive European countries cannot recycle all of their waste. Austria, Germany and Belgium recycle the most – more than 60% of their municipal waste – but still send their residual waste to Waste-to-Energy plants. Only a small fraction of their waste is landfilled.
It is worth bearing in mind that residues from recycling processes often also need to be thermally treated.
About 40% of Municipal Waste in Europe is still landfilled, even though landfill gas (methane) contributes significantly to global warming (25 times more significant in mass than CO2).
The European Landfill Directive sets strict diversion targets for the landfilling of biodegradable waste. The deadline for reducing landfilling by 50% was in 2009 and European Member States that miss this deadline face hefty fines. By 2016 the biodegradable waste being sent to landfills must be reduced by 65% (based on the amount landfilled in 1995).
Landfill not only takes up land that could be better used for other purposes, it buries waste that can be a source of energy - it also significantly adds to global warming.
Member States who landfilled more than 80% of municipal waste in 1995 could apply for derogation on the application of the Landfill Directive by up to 4 years: Bulgaria, Czech Republic, Estonia, Ireland Latvia, Lithuania, Poland, Romania, Slovakia and the United Kingdom. For these Member States the deadlines are 50% by 2013 and 65% by 2020.
Waste-to-Energy plants create jobs – not as many as more manual forms of waste management - but well paid, highly-skilled jobs in good, clean working conditions.
Please follow this link to a Waste-to-Energy plant in Portugal that has won an award for being one of the best employers in the country - www.lipor.pt
Waste incineration was first mentioned in the Bible, with waste being burnt in open fires in Jerusalem (1,000 b.c).
The incineration of waste was also common practice across the Roman Empire.
However, after the fall of the Roman Empire waste incineration fell out of use, with pestilence and cholera becoming rife during the Middle-Ages.
Collection of municipal waste in cities became common practice again in the 16th century. At that time waste was predominately landfilled outside the city gates.
The first waste incineration plant, known as a “Destructor” was built in Nottingham in the UK in 1874.
Waste incineration became established in many European countries at the end of 19th century, as a means of minimizing the volume of waste and destroying the bacteria, germs etc. found in the waste and making it hygienic.
Since then, as environmental awareness has grown, Waste-to-Energy technology has continuously developed and improved, with efficient energy generation becoming increasingly important.
For further information on the history of waste incineration and Waste-to-Energy in Denmark for example, please follow this link to “100 years of waste incineration in Denmark: From Refuse Destruction Plants to High-technology Energy Works”