On the road to fossil-free public transport: The case of Swedish bus fleets

Abstract

Public transport is important for Sweden to acquire a fossil-fuel independent vehicle fleet by 2030. The aim of this paper is to assess the status of Swedish public bus fleets towards decarbonization, and explore factors affecting regional performance variations and fuel choices. Environmental performance indicators such as renewable fuel shares, CO 2 emissions, and energy efficiency are analyzed nationally and regionally. Fuel preferences and best practices are investigated through a survey and interviews with experts working with strategic planning at Public Transport Authorities. Almost 60% of the bus transport volume ran on renewables in 2014 compared to 8% in 2007, but regional variations are significant, partly due to factors such as driving conditions, bus and fuel types, typical trip lengths, and climatic conditions. However, there is no strong correlation between population densities or bus transport volume and the share of renewables achieved. This places political will, strategic planning and policies to promote public transport as key factors affecting renewable fuel deployment. Environmental factors are a priority when choosing fuels, while barriers to renewable fuels are mainly economic and political. Meanwhile, despite the overall progress, achievements in energy efficiency improvement are falling short in comparison to emissions reduction and adoption of renewable fuels, thus requiring further attention.  Electricity is likely to receive increased attention according to expert survey. Highlights

Locating charging infrastructure for electric buses in Stockholm

“…This is in line with previous studies for bus transport in Sweden (SKL, 2014b;WSP, 2014aWSP, , 2014bXylia and Silveira, 2017), which indicate the high impact of O&M costs on public transport costs. Differences between the O&M costs in the BAU and the total system cost and energy consumption optimization scenarios can be attributed to the higher maintenance costs assumed for electric buses compared to the biodiesel buses (see Table 1).…”

“…Moreover, the difference in consumption between dense city traffic and suburban routes for the Swedish case has been previously found to be 14% (Xylia and Silveira, 2017). Such variations in energy consumption are covered from the range of the sensitivity analysis assumed.…”

“…Then as one moves towards the suburbs, biodiesel and biogas could be the fuel options selected. Such an approach would be beneficial for the system's energy consumption, as fuel consumption increases in dense city traffic due to frequent stops, and biodiesel and biogas buses show higher fuel consumption than electric buses in these conditions (Xylia and Silveira, 2017). As a result from the selection process described above, 143 bus routes and 403 existing bus stops are selected as potentially suitable for electrification, and serve as input to the model (see Figure 2).…”

“…There is strong will among local political authorities, and strong involvement of major public transport stakeholders and technology producers in the market which is paving the way in this direction. The next steps in the decarbonization of the transport sector should aim at simultaneous reduction of emissions and improvement of energy efficiency (Xylia and Silveira, 2017). This can be made possible with electric powertrains, which have much lower energy consumption per vehicle-kilometer than the commonly used diesel and gas powertrains (Mahmoud et al, 2016;Tzeng et al, 2005).…”

Dynamic links between ICT, transport energy, environmental degradation and growth: empirical evidence from Tunisia

“…In addition to electrically powered vehicles, there has been no question of making buses less polluting. Nearly 60% of Swedish buses use renewable energies in 2014 compared to 8% in 2007 (Xylia & Silveira, 2017). The emission of CO2 takes an important place since it contributes strongly to the greenhouse effect.…”