Assessing the impacts of market-oriented electric vehicle charging on german distribution grids

Abstract

Market-oriented charging, based on real-time electricity prices, was in a previous study shown to benefit the integration of variable renewable energy sources (VRES) by significantly reducing market-driven curtailment. In this study, we assess the impact of market-oriented charging of electric vehicles (EVs) on medium-voltage (MV) and low-voltage (LV) grids in Germany and compare it to an uncoordinated charging. The analyses are conducted on synthetic grid topologies for a 2030 scenario with 10 million passenger cars. We show that market-oriented charging has different effects on the assessed grid types. In photovoltaics (PV)- and winddominated grids, as well as load-dominated suburban and rural grids, a minor increase in load-driven grid issues is observed, predominantly due to wind-feed-in driven charging peaks in the winter. Feed-in curtailment, however, is slightly reduced, which can mainly be attributed to a reduction of PV curtailment. In urban grids, on the other hand, market-oriented charging results in a significant increase in the number and degree of load-driven grid issues. As urban grids only make up around 7% of German MV grids, the impact for entire Germany is found to be moderate. Assuming load-driven grid issues could be solved by a curtailment of charging demand, it is found that marketoriented charging results in an increased curtailment of only 0.7% of the total charging demand. A sufficiently high benefit in overlaying grid levels could thus outweigh the drawback of increased stress on urban grids.