Across all the operational missions in maritime mobility, ferry crossings are ideal candidates for electrification. The short distance and the possibility of top-up charging at port between crossings make it possible to convert ferries to battery electric propulsion. In this presentation we examine the energy requirements and possibilities to electrify ferries of a typical configuration available between the port of Dover and Calais. Energy requirements across various weather conditions are presented together with available energy from charging, solar power and wind power. The electrical architecture of the ship is presented with a concept modular battery system architecture.