The Carbon Footprint of Electrified City Buses: A Case Study in Trondheim, Norway

In August 2019, a new bus fleet of 36 electric and 58 hybrid buses were implemented in Trondheim, Norway. This paper examines the carbon footprint of electrified city buses, by addressing the achieved and potential reduction for the new bus fleet. Important aspects such as geographical location of production, charging electricity mix, and impact from production and operation on lifetime emissions, are also examined. A meta-analysis on life cycle assessment studies was undertaken to investigate greenhouse gas emissions and energy demand in different parts of bus production. This is followed by the production of a bus model using the findings and comparing electrified buses with diesel and HVO buses. The models were then used in a case study of the bus fleet in Trondheim, to understand the specific parameters affecting the carbon footprint. The results show that the overall carbon footprint has been considerably reduced (37%) by implementing biofuel and electrified buses, and that a further reduction of 52% can be achieved through full electrification. The operation emissions for the fleet were found to be 49 g CO2-eq/person-km, which is lower than the average city bus and passenger car in Norway