Where and when do electric vehicles have the larges environmental benefit

Abstract

Electric vehicles have the important advantage that pollution resulting from energy conversion is not emitted in the same place where the vehicle is driven. Given that urban PM10 concentrations often overshoot European air quality targets, it may be a good idea to keep these emissions away from busy and populated areas. In this paper we take this concept one step further by looking at the time when pollutants are emitted. When electric energy can be locally stored, it can be used whenever it is most useful, not just from a technical but also from an urban air quality perspective. Specific types of vehicles are preferentially used outside rush hours and the timing of specific activities (e.g. collecting garbage or deliveries to urban shops) is adjusted to avoid congestion. We demonstrate that shifting the emission of pollutants to the late evening or early morning, when the atmosphere is relatively more stable can cause an unwanted increase in air pollution even when emissions are constant. Electric vehicles can therefore be much more efficient in reducing environmental impacts at night, when impacts of both noise and air pollution are much more important, but electricity is cheap. The environmental benefits of electric driving is much more important at night than during daytime. From an environmental perspective vehicles that are predominantly operated before sunset or after sunrise should preferentially be substituted by electric or hybrid versions.