Influence of the origin of stored electricity

The climate footprint of electric cars depends to a large extent on the power mix. The use of additional renewable energy gives electric vehicles significant advantages over conventional vehicles in terms of their climate impact – even if the latter are refuelled using biofuels.

If electric vehicles are operated within the average German power mix, their climate footprint is determined primarily by the usage-related emissions in the power stations, despite the additional battery production.This makes the selected power plant complex a crucially influential parameter. For example, if new power stations have to be built to satisfy the additional power requirements for electric vehicles, this leads to a significantly greater climate impact throughout the lifecycle in the case of coal-fired power stations (see Fig. 1). This also applies if the burden on older and inefficient power stations increases due to the additional electricity requirements. However, if modern gas power stations are built for the additional power demand for electric vehicles, this improves the climate footprint.

Fig. 1: The climate footprint of electric mobility depends heavily on the electricity used. (ifeu 2017)

Electric vehicles also facilitate the use of numerous renewable energy sources in transportation, which were not available previously. This improves the climate footprint significantly, as almost no CO2 emissions are generated during use. However, the fact that these are additional facilities that would not have been installed were it not for the operation of electric vehicles is crucial for calculating the renewable electricity for the electric vehicle’s environmental record.

Abb. 2: Comparison of the climate footprint of battery-powered and conventional vehicles. The footprints for electric vehicles are shown for different electricity mixes; those of the combustion vehicles for conventional and average biofuel. (IFEU 2017)

In this case, the climate footprint of electric vehicles is also clearly more favourable than that of conventional vehicles running on biofuels (see Fig. 2). This is because the provision of biofuels is generally associated with a relevant climate impact and higher environmental effects in terms of acidification and eutrophication (e.g. through fertilisation) as a result of agricultural processes. Furthermore, there can be competition for usage and land, which plays only a small role in the generation of renewable electricity.