Mobility

The transport sector consumes 35% of total final energy and accounts for 37% of greenhouse gas (GHG) emissions in Switzerland (FSO 2015). Furthermore, transport related emissions contribute significantly to fine particle, nitrogen oxide, and many other emissions that are harmful to human and ecosystem health. The transport sector is one of three major sectors taken into focus in the Swiss Energy Strategy 2050 (along with buildings and electricity). For these reasons, the Technology Assessment group has developed a strong competence in the assessment of current and potential future transport technologies. Starting with project THELMA (Technology-centered Electric Mobility Assessment), the technology assessment group has developed detailed models of the passenger car fleet in Switzerland. In the Swiss Competence Center for Energy Research in Mobility (SCCER Mobility) these competences are being extended to include the whole transport sector with detailed technology models for passenger and freight transport by road, rail, water and air.

Method

The Technology Assessment group uses all of the methods at its disposal to analyse the transport sector. These methods include: Life Cycle Assessment (LCA), Life Cycle Cost (LCC) analysis, accident risk assessment, Multi-Criteria Decision Analysis (MCDA). Furthermore, specific to the transport sector, the Technology Assessment group uses fleet analysis to examine the potential impacts of new technologies on the overall fleet as well as to discover trends in user preference, such as the increase in average passenger car weight and engine size that has developed over the past decade. Our links to the Energy Economics Group allow us to better understand how the transport sector fits better into the energy sector as a whole, and work is ongoing to further integrate our models.

Figure 1 below shows the methodology used in the SCCER Mobility project to complete an environmental and economic life cycle assessment of the Swiss transport sector. This assessment considers transport modes for water, air, rail, and road. For each transport mode, a list of relevant technologies is generated, considering variations in size, powertrain, energy source and technology level, for both passenger and freight transport. Each of these technologies are the assessed using life cycle methodologies to quantify the costs and environmental impacts per passenger or ton kilometer transported. Finally, the results are scaled up from the level of individual technologies to the sector level by considering the annual transport performance of each technology.

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Figure 1: Methodolgy schematic for the combined environmental and economic life cycle assessment of the Swiss transport sector to be used in the SCCER Mobility project.

Selected Results

1: Project THELMA - Technology-centered Electric Mobility Assessment
The task of the Technology Assessment group in project THELMA was to perform life cycle assessment, life cycle cost analysis, drivetrain simulation and fleet analysis, and integrated assessment using Multi-Criteria Decision Analysis (MCDA) for current and future cars in Switzerland. Figure 2 shows one result of this project on global warming impacts of mid-sized cars produced in 2012 and 2030 with different drivetrains and fuels (Bauer et al., 2015). As can be seen in this figure, hybrid electric vehicles (HEV) are found to cause 10% to 20% fewer life cycle greenhouse gas emissions than internal combustion engine vehicles (ICEV). Fuel cell electric vehicles (FCEV), when fuelled with hydrogen from steam reforming of methane, do not offer climate benefits compared to conventional technologies. Battery electric vehicles (BEV) were found to already offer greenhouse gas reductions in 2012 when charged with average European electricity, and these reductions are expected to be much higher in 2030 if the average climate impacts of the European electricity grid are reduced according to forecasts.

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Figure 2: Life-cycle GHG emissions of selected mid-size passenger vehicles with different drivetrains and fuels. Source: Bauer et al. (2015)

2: Project Swiss Competence Center for Energy Research in Mobility
The task of the Technology Assessment group in this project is to extend the work done in project THELMA and perform life cycle assessment, life cycle cost analysis, drivetrain simulation and fleet analysis for all major current and future passenger and freight transportation modes in Switzerland. Figure 3 below shows results for the life cycle global warming impacts of narrow body airplanes and how they develop over time, as presented by Cox and Jemiolo (2015). These results show that the most important contributor to global warming from aircraft travel is fuel consumption. This is due not only to the combustion of the jet fuel itself, but also to the greenhouse gas emissions released during crude oil production and refining. Aircraft fuel consumption has improved significantly since 1990, and is expected to continue to do so in the future, which is found to greatly reduce the environmental impacts of air travel.

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Figure 3: Life-cycle GHG emissions of large narrow body aircraft with construction years from 1990 to 2050. Source: Cox and Jemiolo (2015)

3: Project Swiss Competence Center for Energy Research in Mobility
Figure 4 shows a further result from the SCCER Mobility project (Cox and Mutel, 2015). This is a fleet level assessment of motorcycles in Switzerland from 1990 to 2050 for a scenario where all conventional motorcycles are gradually replaced by battery and fuel cell powered motorcycles. Results are quantified for climate change (CO2 eq), terrestrial acidification (SO2 eq), photochemical oxidant formation (NMVOC eq) and particulate matter formation (PM10 eq). The baseline results are shown for electric motorcycles charged with electricity from natural gas combined cycle power plants and fuel cell motorcycles fuelled by hydrogen from steam reforming of methane. The black lines show sensitivity results where electricity and hydrogen are sourced from hydropower and coal respectively. The replacement of conventional motorcycles with advanced motorcycles is found to have a dramatic impact on photochemical oxidant formation potential (summer smog) regardless of the energy source for electricity and hydrogen. Similar results are found for particulate matter formation, though less dramatic. Climate change benefits resulting from converting the motorcycle fleet to advanced power trains are found to depend on the primary energy source used, with hydroelectricity proving promising.

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Figure 4: Life-cycle environmental impacts from Swiss motorcycle fleet from 1990 to 2050. Results are from a scenario where battery and fuel cell electric motorcycles make up over 60% of the fleet by 2050. Electricity and Hydrogen are generated from natural gas (base case), hydroelectricity (solid line) and coal (dotted line). Source: Cox and Mutel, 2015

Selected Publications