Waste-to-Energy Plants - apart from fulfilling their task of a safe waste disposal/recovery system - contribute to energy supply, providing electricity, district heating and process steam. This (partly) replaces the energy produced by conventional power plants and other energy producing processes.

In addition, the optimal energetic efficiency degree from the technical point of view was examined and the factors which complicate the extension of energy utilisation from waste incineration plants.

The study shows which performances waste incineration can achieve to provide to clean air today and which efforts are linked to this. The main emphasis on the study lies in the search for the contributions of waste incineration to the emissions of relevant climate change gases.

Thus, the biogenic carbon content of the waste plays an important role because the CO₂-emissions resulting from it do not contribute to climate change.

The part of renewable carbon in waste is about 62 % of the total carbon content according to the scientists of the Öko-Institut. This corresponds to an energetic content of about 82 PJ, which could be considered as climate-neutral.

In addition, the group of pollutants contributing to acidification of eco-systems was considered, i.e. NO_x and SO₂. The pollutant dust also plays an important role because of its effects on human beings and this is why it was looked at as a single parameter in the study. The contribution of waste incineration to the protection of resources was also determined.

1. Waste incineration plants provide a worthy contribution to climate protection.
2. They contribute less to the acidification of eco-systems than, for example, power plants.
3. They protect resources.

To 1: The results state clearly that incineration of waste in waste incineration plants is more or less CO₂-neutral. The reason is the high content of biogenic CO₂ in waste.

The scientists from Öko-Institut also found that incineration plants could improve the result by raising the heat release.

To 2: Concerning the categories "acidification of eco-systems" and "dust" the results are also positive. The consequent reduction in pollutants in waste incineration plants leads to very low emissions (far under the 17. BImSchV = German Emissions Ordinance). Flue gas cleaning systems of waste incineration plants have reached a high standard in Europe and in the world.

To 3: Concerning the category "protection of resources" also a clear positive result is given.

Recommendations of Öko-Institut:

Energy release from incineration plants could be optimised. Many, as yet unexploited measures and the promotion of cogeneration would improve energy use. In addition, the release of heat should be optimised. The more waste incineration plants are optimised the more advantages they could reach regarding the greenhouse effect.

So waste incineration plants can provide a worthy contribution to the aims of climate protection!

The German Federal Environment Agency notes in a report from July 2002 that the 13 million tons of municipal waste which were incinerated in 2000 in 56 incineration plants, produced 14 million MWh/a of energy and reduced 4 million tons CO₂/a by substituting fossil produced energy.

If further 13 million tons of municipal waste, which are still landfilled, would be used energetically in waste incineration plants per annum, the contribution of these plants to CO₂-emissions reduction would be 6.4 million tons CO₂.

If energy use would be improved, which is possible with some optimising measures, an additional 3.4 million tons of CO₂-emissions could be saved every year.

• Öko-Institut Darmstadt, 2002: "Der Beitrag der thermischen Abfallbehandlung zu Klimaschutz, Luftreinhaltung und Ressourcenschonung"
• Bernt Johnke, Umweltbundesamt Berlin: "Statusbericht zur Einsparung von CO₂-Emissionen durch verbesserte Energienutzung in Siedlungsabfall-Verbrennungsanlagen - Stand Juli 2002"