Home or workplace charging? Spatio-temporal flexibility of electric vehicles within Swiss electricity system

Electrification of the transport sector is crucial for achieving carbon neutrality. With increasing number of electric vehicles, attention to controlled charging as a means to provide flexibility to the electricity system with high shares of renewable generation is rising. This study explores the implications of spatially shifting electric vehicle charging load with the focus on home vs. workplace charging in Switzerland in 2035. The study applies a spatially-explicit electricity system optimization model EXPANSE with a resolution of 2′169 Swiss municipalities, combines it with a vehicle commuting matrix, and optimizes the charging of electric vehicles used for commuting purposes between the municipalities of home and workplace. The results show that workplace charging can reduce the need for electricity import and storage and promote solar photovoltaic integration unless the shares of renewable generation are already high, hence benefiting the whole system. The optimal share of workplace charging is over 90 % from the electricity system's perspective if all private vehicles in Switzerland are electric vehicles. Workplace charging is systematically preferred in northern and western Switzerland. This study highlights the potential of spatially-optimized electric vehicle charging to enhance the flexibility and efficiency of the electricity system for the broader goal of decarbonizing both the transport and electricity sectors.