Bidirectional charging holds significant potential for integrating renewable energy and reducing system costs in Europe’s energy transition. However, these benefits only materialize when electric vehicles actively participate in Vehicle-to-Grid (V2G) applications rather than solely optimizing self-consumption via Vehicle-to-Home (V2H). In Germany, state-induced price components – especially grid fees – continue to hinder the economic viability of V2G. While taxes and levies are being addressed, grid fees remain a barrier to intermediate storage of grid electricity. A blanket exemption would unfairly shift costs to other users. With this paper, we explore Flexible Connection Agreements (FCAs) to ensure grid-neutral charging and discharging, enabling targeted reimbursement of grid fees. Using our GridSim model, we assess grid load, energy subject to charges, and expansion costs across use cases. We also implement an envelope concept to temporarily limit charging processes and reduce grid impact. Our goal is to support the intelligent, scalable design of FCAs and contribute to reforming grid fee structures. This would incentivize system-friendly flexibility from mobile storage systems while ensuring fair cost allocation and preserving viable business models