The development of new vehicle concepts, amongst others, aims to address current challenges in traffic and environmental protection. The modular vehicle concept U-Shift, which is being developed by the German Aerospace Center (DLR), promises a high operating efficiency through an on-the-road modular design and the associated possibility of distributed energy storage. The U-Shift consists of a driverless drive unit and various application-specific transport capsules. This work addresses a key research question of how the U-Shift's distributed energy storage systems must be designed to accommodate the most extreme case of a 24-hour operation without requiring idle time for grid charging. For this purpose, a simulation model of the U-Shift was developed in Dymola. The battery configuration was optimized regarding to a generic use case. As a result, a minimum energy content of the batteries of the drive unit and each capsule type was computed to enable a theoretical 24-hour operation.