Impacts of electric vehicle charging under cold weather on power networks

Deep decarbonisation of the transportation requires widespread adoption of electric vehicles (EVs). Currently, the dominant energy storage technology for EVs is lithium based batteries which are designed to work under mild ambient temperatures (e.g. 21 Celsius). However, most cities with high EV penetration experience cold winter months when the performance of EVs is significantly degraded. In this paper, we present an impact assessment of cold weather EV charging on the power networks by reviewing existing literature on empirical studies related to battery performance, EV driving range, and charger characteristics. Two potential issues are identified. First, charging EVs at low temperatures significantly increases distribution network harmonics, hence limits the number of EVs that can be charged at the same time. Second, more frequent charging of EVs increases demand from the grid. To quantify this, a Monte Carlo based simulation is developed for the case of UK and results show that nearly 450 MW of extra generation is needed to cushion impacts of cold weather charging of 11 million vehicles. The problems pertinent to temperature effects on EV charging require greater attention as EVs are becoming the main mode of transport in the next decade.