A case study of enhancing energy efficiency in battery-electric ferries through low-temperature heat pump integration

This case study examines the potential for energy savings in all-electric battery-driven ferries through the integration of water heat pumps that utilise low-temperature waste heat for on-board heating. The principal objective is to enhance both energy efficiency and economic viability. A hybrid-driven diesel-battery-powered roll-on/roll-off passenger ferry operating in the Baltic Sea is analysed, using real-time data from power and heat flow measurements, energy flow analysis, and thermodynamic calculations. The study investigates the potential for retrofitting a 10 MWh battery system for full battery-electric operation. The findings indicate that heat pumps could satisfy over 50% of the HVAC nominal heat requirements, achieving a seasonal coefficient of performance (SCOP) of 3.5. The integration of heat pumps has the potential to reduce the vessel’s electric demand by 9.5% during a heating season, in comparison to direct electric heating.