International Nordic Bioenergy 2003 conference SURVEY OF FARM BIOGAS PLANTS WITH COMBINED HEAT AND POWER PRODUCTION IN AUSTRIA

The number of farm-based biogas plants in Austria increased rapidly in the recent past, a continuing interest in this technology is expected. A survey was carried out in 2002 to provide information for farmers and the decision makers involved. In most plants slurry and manure is co-digestion with energy crops and/or organic waste. Wet fermentation in mesophilic digesters with post-digesters combined with separate storage tanks is the main technology used. The trapped biogas is utilized in CHP-units and the electricity is sold to the grid. The waste heat is supplied to the farm and farm house, only a few sell it for district heating. The labour requirement depends on the fermented feedstock. Slurry and manure cause the lowest and the co-digestion of organic waste the highest labour requirement. The survey results indicate a distinct decrease in investment costs per unit. On average 75 % of the capacity of the farm-based biogas plants are used. Most farmers intend to increase production at higher electricity prices. Further reasons to produce more biogas would be the abandonment of livestock husbandry or direct payments for energy crops.