Is The Electric Car Really Helping The Environment?

Electric vehicles (EVs) are becoming more prevalent in the US and European transportation markets, as evidenced by the introduction of new EV models from car producers, such as Ford, Mercedes, Nissan and Tesla Motors. Moreover, the increasing economic popularity of EVs is shown by Tesla Motors’ recent profitable quarters this year. A major reason why EVs are gaining popularity is their claim to reduce greenhouse gas (GHG) emissions and to be more beneficial from the environment. Even though that theory may make intuitive sense, a critical look at the system surrounding EV and internal combustion engine vehicles (ICEV) reveals that the reality is more complicated and that the environmental benefits of EVs depends greatly on external factors.

In a recent study Hawkins, Singh et al. conducted a comparative life-cycle analysis of EVs and ICEVs with focus on the environmental impacts of the two car models. The study showed that current production methods of EVs are significantly more environmentally damaging than the production of ICEVs. This is mostly due to the power mechanism manufacturing techniques, including battery manufacturing, in EVs that involve energy intensive processes. The high environmental cost of EV production, however, can often be offset by the lower GHG emission of EVs during their use-phase. The GHG footprint of EVs during their use-phase, however, depends highly on the electricity infrastructure in place for a given region and the benefits scales with the lifetime of the EV. Disposal and other end-of-life processes had nearly equal environmental impact for both EVs and ICEVs.

With current production processes, the EV requires a minimum lifetime 100,000 km (62,000 miles) to be competitive with ICEV in GHG footprint. Assuming a lifetime of 150,000 km for an EV (93,000 miles), the electricity infrastructure becomes the dominant factor for the GHG impact of the EV. The life-cycle analysis study analyzed the environmental impacts for three different electricity infrastructures: the European energy infrastructure (shown in the Figure 1 below), a natural gas dominated electricity grid and a coal dominated grid. Under the European energy grid, EVs outperformed ICEVs by about 20% for gasoline ICEVs and 10% for diesel powered ICEVs in GHG footprint. For a natural gas dominated energy grid, EVs still outperformed gasoline ICEVs by 12%, but broke even with diesel ICEVs. In the case of a coal-dominated energy, however, EVs actually increased GHG emission by 17% when compared to ICEVs and 27% for diesel ICEVs.

Figure 1: European Energy Sources in 1990 and 2009 by fuel (Source: European Commission – Market Observatory for Energy)

Using an electric car can be environmentally beneficial depending on where in you live. Fortunately, in the United States, as seen in the map below, EVs have a positive environmental impact in the majority of the states. In California, it is particularly beneficial to own an EV since the electricity grid for California generates even less GHG emissions for EVs then the European mix.

US Map by EV Environmental Impact - EV use decreases GHG emissions in green states and increases GHG emission in black states

Figure 2: US Map by EV Environmental Impact – EV use decreases GHG emissions in green states and increases GHG emission in black states (Data provided by U.S. Energy Information Administration)

Another important conclusion to be drawn from the interconnection of electric vehicles with the electricity grid is that energy issues truly require a holistic systems approach, since many factors are inevitably interlinked.