Dynamic Grid Tariffs for Electric Vehicle Charging: Results from a Real-World Experiment

Shifting the charging demand of electric vehicles away from peak load times is regarded as one of the most important challenges to keeping electricity grids operational. One way to achieve this is through dynamic grid tariffs. Dynamic grid tariffs provide a financial incentive to charge point operators and EV owners to move the charging demand of electric vehicles to moments at which the grid is not congested. In this work, a novel stacked dynamic grid tariff system is proposed. This grid tariff system is applied to electric vehicle charging in a large- scale, real-world experiment. This experiment is conducted at >150 low-voltage grids and >300 public charging stations in the city of Utrecht, the Netherlands. This work provides insight into the practical potential of mitigating grid congestion problems by reporting the results of the experiment for five grids. The results of this experiment are that the share of time with grid congestion is reduced by 21% compared to uncontrolled charging. In addition, model simulations have been performed to analyze the theoretical potential of the proposed system in contributing to the mitigation of grid congestion problems. Theoretically, the share of time with grid congestion can be reduced to 0.9% of the time, but the difference with day-ahead market optimization without considering grid tariffs is marginal. Furthermore, the results of this study show that the effectiveness of the grid tariff system can be considerably increased if no minimum charging current for EV charging is required.