Methane - fuelled buses
Natural gas and biogas have been considered as inherently “clean” fuel options with considerable potential for further development. Low levels of NOX and particulate emissions are two main advantages. However, the introduction of cleaner diesel fuel and the use of aftertreatment devices such as, e.g. catalytic particulate filters have also decreased the emissions from these buses. Recently, the emissions from buses fuelled by natural gas have been in the focus in the USA. There are relatively few recent data on emissions from gaseous-fuelled city buses in Sweden. The scope of this work has been to summarise the experiences from international activities and, based on the knowledge gained, propose a test programme for tests on gaseous-fuelled buses and their diesel-fuelled counterparts.