Reduction of carbon dioxide and nitrogen oxides emissions from combustion engines of vehicles by using biomethane

This paper discusses generally the possibility of reduction carbon dioxide and nitrogen oxides emissions from internal combustion engines of vehicles by using biomethane. The road transport in Europe almost fully depends on fossil fuels. Diversification of the road transport fuels will be a key attribute for road transport in the coming years. Purified biogas is one of alternative renewable fuels. Actually, in Poland biogas is used for generating electricity and heat. In some countries (for example in Sweden), upgraded biogas to natural gas quality (biomethane) is used as a vehicle fuel too. In this paper estimated biogas production potential in Baltic See Region countries: Poland and Sweden. It was one of the purposes of European Project Baltic Biogas Bus, and it is taken into account in European Project More Baltic Biogas Bus realized presently. Comparative studies of exhaust emissions of carbon dioxide and nitrogen oxides from city buses powered by diesel and CNG engine were carried out. The study was conducted under real traffic conditions in southern Polish city Rzeszow. Due to the lack in-service city buses with emission level Euro V in Rzeszow, comparative studies of this type of city buses powered by diesel and CNG engine was conducted in SORT I test. Determined mean values of road emissions of carbon dioxide and nitrogen oxides in g/km for the city buses operated in Rzeszow. Estimated value of the total road emissions in the case that would be replaced half the fleet of city buses (40 CNG buses and about 35% of the diesel engine powered buses, meet Euro III emission standard) by the CNG-powered (biomethane) city buses, complying with Euro V (EEV) emission standard.