Various studies have shown that bidirectional charging has immense potential in Europe to integrate more renewables into the electricity grid and reduce the dependence on large-scale stationary storage and backup power plants. All in all, bidirectional charging can significantly reduce the costs of the energy transition. Yet, we observed in the previous BDL project that these systemic benefits can only be unleashed if the electric vehicles (EVs) are also connected to the power grid and participate in Vehicle-to-Grid (V2G) use cases instead of Vehicle-to-Home (V2H) optimization.

In addition to other regulatory hurdles, the attractiveness of V2G use cases in Germany still suffers from the state-induced price components (SIP) such as taxes, levies, and grid fees. Grid fees are charges imposed by electricity grid operators to cover the costs of maintaining and operating the electrical grid. With V2H there is an opportunity to save costs by optimizing self-consumption and reducing the consumed electricity from the grid. The use case must therefore increasingly face the accusation of de-solidarization, as the grid connection continues to be used with temporary high power peaks, but fewer grid fees are raised in a volumetric charging system.

While for taxes and levies, solutions were already implemented or are about to be – greed fees remain a burden for the intermediate storage of electricity from the grid. An unconditional exemption from grid fees for V2G would thus shift the financial burden to other grid users. To counteract this, it would have to be ensured that V2G charging and discharging processes do not place an additional load on the grid and therefore do not generate any costs. Within BDL Next, we want to utilize the concept of flexible connection agreements (FCAs) to ensure a proactive grid neutrality of charging events and compensate these temporary restrictions with a reimbursement of grid fees for temporarily stored grid electricity.

With our Electric Grid and Energy System Model for Distribution Grids (GridSim) we evaluate the consumed kWh subject to grid charges as well as the resulting grid load and grid expansion cost for the different use cases. Via this comparison we want to shed light on the debate of de-solidarization of V2H-Participants and analyze under which circumstances grid fee reimbursements for V2G justified. To achieve this, we also model an implementation of an envelope concept to temporarily restrict the charging and discharging power of bidirectional vehicles and thus reduce grid costs.

With our findings, we want to contribute to the intelligent and scalable design of FCAs in the V2G context. We further want to provide an impulse for the upcoming amendment of the grid fee systematics to incentivize system-beneficial flexibility of (mobile) storage systems and adequately involve them in grid costs without stalling their business models through high fees.