Miljö- och samhällsekonomisk analys av behandling av biologiskt avfall
Biogas is a renewable fuel that can be extracted from anaerobic digestion of many differentsubstrates, for example biological household waste. An alternative handling of the waste is tomix it with other wastes and incinerate it in a combined heat and power (CHP) plant. Thisstudy uses life cycle assessment to investigate which type of waste handling that is betterfrom an environmental point of view, anaerobic digestion with biogas production orincineration. The results are based on a case study of a biogas production plant owned by thecompany Ragn-Sells in Vänersborg. The alternative is incineration at a CHP plant inGothenburg. Three different weighting methods were used, which produced different resultson the detailed level. Overall however, the alternative with digestion and biogas productionhad significantly lower potential environmental impact than incineration according to all threemethods. An economic valuation of the biogas production potential showed that the biggestsocietal savings would result from using all the produced biogas in heavy vehicles or toreplace fuel oil for heating. However, since biogas is a high quality fuel it should be used astransportation fuel rather than for heating. By digestion and biogas production many potentialservices are gained from the organic waste. Waste volumes are reduced, emissions from thetransport sector are reduced, local air quality is improved and valuable nutrients are returnedto farmland through the organic fertilizer produced. The infrastructure and knowledge built uparound the biogas system is also very valuable as a bridge to future gas based transportsystems.