Biogas från gödsel och gräs i kombination med dikalvsproduktion : möjligheter och begränsningar

Abstract: Sweden has great potential for biogas production from manure, residues and energy crops. The environmental benefits are substantial, as the biogas production system reduces emissions from manure pits. The produced biogas can then also do well by replacing environmentally harmful electricity production or fuels. In this project a model farm is studied. Specifications are taken partly from a real farm, and partly from assumptions based on literature and interviews. The model farm is 355 hectare, and has beef cattle production. The farm is expanding its grassland areas and the excess of grass production can be used as a substrate in a biogas plant, in combination with manure. This study also evaluates different promising energy grass varieties for biogas production, and in these comparisons reed canary grass and tall fescue get the best result. Furthermore two scenarios are developed, based on information from the model farm. Scenario A deals with the construction of a biogas production plant at a single farm and Scenario B is based on a larger cooperative biogas factory with vehicle gas production. In scenario B it is proposed that the substrates from a larger constellation of substrate providers are digested together. The result shows that it can be difficult to reach financial profitability for scenario A, especially without governmental subsidies. Scenario B shows better profitability, but only if the produced gas can be sold at a sufficiently high price. The environmental benefits from the introduced biogas system are expected to be greatest in Scenario A, but only if the produced electricity is assumed to replace fossil-based electricity.