10.3.4 CO2 from waste incineration
Compared to landfilling, waste incineration and other thermal processes avoid most GHG generation, resulting only in minor emissions of CO2 from fossil C sources, including plastics and synthetic textiles. Estimated current GHG emissions from waste incineration are small, around 40 MtCO2-eq/yr, or less than one tenth of landfill CH4 emissions. Recent data for the EU-15 indicate CO2 emissions from incineration of about 9 MtCO2-eq/yr (EIPPC Bureau, 2006). Future trends will depend on energy price fluctuations, as well as incentives and costs for GHG mitigation. Monni et al. (2006) estimated that incinerator emissions would grow to 80–230 MtCO2-eq/yr by 2050 (not including fossil fuel offsets due to energy recovery).
Major contributors to this minor source would be the developed countries with high rates of incineration, including Japan (>70% of waste incinerated), Denmark and Luxembourg (>50% of waste), as well as France, Sweden, the Netherlands and Switzerland. Incineration rates are increasing in most European countries as a result of the EU Landfill Directive. In 2003, about 17% of municipal solid waste was incinerated with energy recovery in the EU-25 (Eurostat, 2003; Statistics Finland, 2005). More recent data for the EU-15 (EIPCC, 2006) indicate that 20–25% of the total municipal solid waste is incinerated at over 400 plants with an average capacity of about 500 t/d (range of 170–1400 t/d). In the US, only about 14% of waste is incinerated (US EPA, 2005), primarily in the more densely populated eastern states. Thorneloe et al. (2002), using a life cycle approach, estimated that US plants reduced GHG emissions by 11 MtCO2-eq/yr when fossil-fuel offsets were taken into account.
In developing countries, controlled incineration of waste is infrequently practised because of high capital and operating costs, as well as a history of previous unsustainable projects. The uncontrolled burning of waste for volume reduction in these countries is still a common practice that contributes to urban air pollution (Hoornweg, 1999). Incineration is also not the technology of choice for wet waste, and municipal waste in many developing countries contains a high percentage of food waste with high moisture contents. In some developing countries, however, the rate of waste incineration is increasing. In China, for example, waste incineration has increased rapidly from 1.7% of municipal waste in 2000 to 5% in 2005 (including 67 plants). (Du et al., 2006a, 2006b; National Bureau of Statistics of China, 2006).