Diffusion of electric vehicles and their flexibility potential for smoothing residual demand - A spatio-temporal analysis for Germany

The transformation of the energy system is causing stress on distribution grid components. However, flexible charging of electric vehicles has been shown to have the potential to mitigate this impact by reducing load and feed-in peaks. To understand the potential of charging flexibility on regional and national levels, regional residual demand time series for Germany are estimated for the years 2019, 2030 and 2045. The diffusion of electric vehicles is modeled via sigmoid functions and driving and charging profiles are derived based on micro mobility data. Furthermore, two flexibility schemes for electric vehicles are distinguished: (1) all vehicles contribute to flattening the national residual load curve; (2) vehicles contribute to flattening regional residual load curves. The analysis shows that although the absolute flexibility potential increases with the number of vehicles, its marginal utility to reduce load peaks declines. In load-dominated regions, the national deployment of flexibility can result in higher regional demand peaks compared to a scenario without charging flexibility. The two approaches of flexibility activation can be contradictory in their effects: While regional incentivization is less efficient in reaching the smoothing in the national residual demand curve, national incentivization can even lead to increased strain on the local level.