An Overview of the Global
Waste-to-Energy Industry
Article by Nickolas J. Themelis in
Waste Management World (http://www.iswa.org/),
2003-2004 Review Issue, July-August 2003, p. 40-47
Despite the expansion of the global waste-to-energy (WTE) industry in the past decade, hundreds of millions of tonnes of municipal solid wastes still end up in landfills. For every tonne of waste landfilled, greenhouse gas emissions in the form of carbon dioxide increase by at least 1.3 tonnes. This article provides an overview of the WTE industry, and reviews recent advances made in the US in decreasing dioxin and mercury emissions. The recently established Waste-to-Energy Research and Technology Council hopes to bring together global academic and industrial expertise with the aim of improving WTE technologies.
Worldwide, about 130 million tonnes of municipal solid waste (MSW) are combusted annually in over 600 waste-to-energy (WTE) facilities that produce electricity and steam for district heating and recovered metals for recycling. Since 1995, the global WTE industry increased by more than 16 million tonnes of MSW. Currently, there are WTE facilities in 35 nations, including large countries such as China and small ones such as Bermuda. Some of the newest plants are located in Asia.
According to a directive from the European Union,1 landfilling of combustible materials must be phased out within the decade. However, it is not clear that the capital investments required will be made by all of the member countries. Some of them have little WTE capacity and some – for example, Greece – none at all. The current EU installed capacity and per-capita use of WTE for the disposal of municipal solid waste is shown in Table 1.2 For comparison, the use of WTE amounts to 314 kg per capita in Japan, 252 kg in Singapore, and 105 kg in the US. One of the newcomers to WTE is China, with seven plants in operation and an estimated annual capacity of 1.6 million metric tonnes per year.
Current state of the global WTE industry
A 2002 review of the European WTE industry by the International Solid Waste Association showed that the total installed capacity was more than 40 million tonnes per year and the generation of electrical and thermal energy was 41 million GJ and 110 GJ, respectively (Table 1). It should be noted that, in contrast to Europe, the US makes very little use of the exhaust steam from the power-generating turbines for either district or industrial heating. A good example of cogeneration of thermal and electric energies is the Brescia WTE facility in Italy (see page 45) that provides an estimated 650 kWh of electricity per tonne of MSW combusted. In the cold season, it supplies at least as much energy as for district heating.3
Table 1. Reported WTE capacity in Europe2
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The US WTE industry represents about 23% of the global capacity; 66% of that is concentrated in seven states on the East Coast (Table 2).
Table 2. Major users of WTE in the US4
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Current state of WTE technology
The dominant WTE technology is mass burning, because of its simplicity and relatively low capital cost. The most common grate technology, developed by Martin GmbH (Munich, Germany), has an annual installed capacity of about 59 million metric tonnes. The Martin grate at the Brescia (Italy) plant is one of the newest WTE facilities in Europe. Figure 1 shows a schematic diagram of its mass-burn combustion chamber. The Von Roll (Zurich, Switzerland) mass-burning process follows with 32 million tonnes worldwide. All other mass-burning and refuse-derived- fuel (RDF) processes together have a total estimated capacity of more than 40 million tonnes.
