Adding gas from biomass to the gas grid - SGC

7 INTERNATIONAL PERSPECTIVE7.1 AVAILABILITY OF BIOMASS7.1.1 AustriaThe most common type of plants for biogas production in Austria are digesters at municipal sewagewater cleaning facilities. Since it has become obvious that methane is accountable for a significantpart (13%) of the greenhouse effect caused by human activity, the recovery of biogas gains specialimportance. Both recovery of landfill gas and the conversion of organic materials to biogas areimportant for minimising methane emissions to the athmosphere. After a series of setbacks withbiogas plants in the early seventies there have been several successful applications in Austria inrecent years which have contributed to the increased importance which biogas technology enjoystoday.Biogas in agricultureThe advantages of biogas utilisation in agriculture are numerous: it represents a renewable energysource, an environmentally sound way of organic waste disposal and organic fertiliser production,and significantly reduces bad smell. Biogas is typically utilised in combined heat and powerinstallations, whose excess power is fed into the grid. Occasionally substances such as vegetableand other food residues or oil are added. In order to encourage the further development of thispotential a fund has been set up to subsidise the installation of biogas systems by agriculturaloperators.Landfill gas recoveryEven though the existing potential is far from being exhaustively utilised, landfill gas is continuallygaining in importance. Besides several smaller installations, the gas from Vienna's largest landfill atRautenweg has been recovered for energy production since 1991. This plant with an electric powercapacity of 8 MW is currently (1996) the largest in Europe [lit.48]. Biogas is produced in 196 plantsof different kinds (1996). The distribution of plant types is shown in table 32.Plant typeNumberFarm plants 58Co-digestion plants 3Industrial plants 6Municipal sludge digesters 118Landfill gas recovery plants 11Total 196Table 32: Biogas plants in Austria (1996)The most important renewable sources of energy are hydropower with a share of 13%, and the socalledother energy sources, which is mainly biomass, with also 13%. This puts Austria third inpage: 79