Potential impact of controlled electric car charging and vehicle-to-grid on Germany’s future power system

Abstract: The increasing diffusion of electric vehicles contributes to a growing electricity demand in the coming years. At the same time, this integrates millions of mobile storage units into the electricity system, which has a rising need for flexibility to balance the intermittent generation from photovoltaic systems and wind turbines. To capture the potential of electric cars as a flexibility resource, we simulate 7,000 vehicle driving profiles in an agent-based model, generating load profiles as well as charging power and state-of-charge boundaries for the German car fleet, which serve as restrictions in energy system optimization. In a scenario-based study for Germany in 2030 and 2045, we compare the installed electric capacities in the optimized system, depending on whether electric vehicle charging is uncontrolled, controlled, or bidirectional. Here we show that a bidirectionally charged car fleet has the potential to replace 32 GW (84 %) of stationary battery storage and 31 GW (64 %) of hydrogen-fired peaking power plants, while enabling an additional solar power expansion of 7 GW (2 %) until 2045. Notably, implementing vehicle-to-grid can limit hydrogen-fired electricity generation to winter months and enable a shift toward combined heat and power plants. On the demand side, it can reduce the expansion of electrolyzers by 19 GW (28 %) and power-to-heat capacities by 25 GW (60 %). Overall, the integrated energy system can substantially benefit from the implementation of smart and especially bidirectional charging as it lowers the need for future capacity expansion in the electricity system but also in coupled hydrogen and heat systems.