Leible, L.; Arlt, A.; Fürniß, B.; Kälber, S.; Kappler, G.;
Lange, S.; Nieke, E.; Rösch, Ch.; Wintzer, D.
Karlsruhe: Forschungszentrum Karlsruhe 2003
(Wissenschaftliche Berichte, FZKA 6882, 278 Seiten)
Current political objectives and requirements on both the national and EU level aim at raising significantly the share of renewable energy sources in energy supply. High expectations are mainly tied to the use of biomass for energy, in particular of biogenic residues and waste. The main focus here is on reducing the emissions of greenhouse gases. Against this background, a systems analysis was conducted by ITAS - funded by the German Federal Ministry of Consumer Protection, Food and Agriculture (BMVEL) - with the objective to analyse and assess the chances of utilisation of biogenic residues and waste for energy. Based on the results, recommendations for a modification of the given framework conditions and promotion strategies are developed.
Initially, volumes and compositions of the biogenic residues and waste that are available in Germany and suitable for energy use, were estimated, supplemented by corresponding analyses of EU member states. This was followed by detailed process chain analyses of the supply (gathering, conditioning, transport, storage) and use of biogenic residues and waste for heat and electricity production.
In Germany, the annual volume of biogenic residues and waste available for energy use amounts to about 75 million Mg of dry organic matter (dom), above all wood residues from forestry and industry, waste wood, cereal straw and liquid manure. Furthermore, 5 to 15 million Mg dom from agriculture and industry could be made accessible. The amount of 75 and 90 million Mg dom corresponds to about 9 and 11 % of the present primary energy consumption, respectively, and is far from being marginal.
Comparison of the different technologies reveals that the present production costs of heat and electricity from biogenic residues and waste are not yet competitive with those of fossil alternatives. Apart from co-combustion and co-gasification in hard coal power plants, the large biogas and sewage gas plants may be the first to achieve competitiveness.
In comparison to other instruments of CO2 reduction, the achievable CO2 mitigation costs of the technologies considered in this study, such as biogas and sewage gas utilisation as well as the combustion and gasification of biogenic residues and waste, are very interesting. Although the achievable employment effects are acknowledged as positive spin-off, they cannot be given as a major reason for promoting the use of biogenic residues and waste for energy supply.