Local Freshwater and Carbon Impact of Electric Mobility

Abstract

The use of electric transportation is growing rapidly. The global electric vehicle (EV) stock reached over 1,2 million vehicles in 2015, which is almost seven times the stock in 2012. It is expected that this increase will continue in the coming decades. The use of EVs, however, can have a significant freshwater and carbon impact as a result of the production of the required electricity. In times when freshwater is becoming a scarce resource in multiple regions worldwide, a methodology is required to assess to local impact of EV usage. This study has developed a methodology to assess the freshwater and carbon impact of EV usage in a region, based on the local electricity mix and water scarcity. The methodology is demonstrated by implementing it to California (United States), Rajasthan (India) and the Netherlands.

Based on the findings in this study it can be concluded that the local freshwater impact of EV usage is small in most regions, even when 50% of the existing passenger car fleet is electric. In regions with a large existing freshwater footprint, which is often a result of intensive agriculture, the relative contribution of EV usage to the total freshwater consumption is only minimal. This can be seen in California and Rajasthan, where an EV deployment of 50% leads to a freshwater consumption of less than 0,5% of the total annual freshwater consumption. In regions with a lower existing freshwater footprint the relative impact of EV usage is much larger, which can be seen in the Netherlands. However, in the Netherlands freshwater scarcity is low, resulting in no problematic impact of EV usage. Only in regions with a small existing water footprint in combination with high existing water scarcity, EV usage is expected to significantly contribute to more local freshwater scarcity.

The local carbon impact of EV usage strongly depends on the region. In Rajasthan the CO2 intensity of EVs is 171 g/km, while in California and the Netherlands the intensity is only 44 g/km and 85 g/km, respectively. Variations are the result of differences in the efficiency and composition of the local electricity mix. Decreasing the carbon impact of the electricity mix, however, can result in a significant increase of the freshwater impact. The average freshwater consumption of geothermal generators, for example, is almost four times higher than the average consumption of fossil fuelled generators. The freshwater consumption of hydroelectric generators is even more than 10 times higher. Therefore, a small carbon impact of EV usage does not inherently mean that the freshwater impact is also small.