Potentials and limitations of battery-electric container ship propulsion systems

The defossilization of the open-sea ship traffic can most definitely only be achieved with alternative energy carriers. Besides synthetic fuels, battery-electric propulsion is a much-discussed measure, especially for smaller vessels and short passages. However, there is no consensus on quantitative ship characteristics that would allow for the application of batteries instead of a fuel-based solution. Therefore, limitations of battery propulsion systems are assessed for 45 vessels with a range of transport capacities. The most common marine battery technologies are evaluated both economically and environmentally by directly comparing their performances with state-of-the-art combustion engines. Mass and volume limitations of the ship are monitored, and emerging opportunity costs are quantified in addition to capital and operating expenses.The application of battery-electric propulsion systems is found not to be limited by the vessel size but mostly by the operated passage length. While distances of up to 15,000 km are technically achievable, economic limitations are effectively reducing the area of application to a maximum of 10,000 km. However, when comparing battery solutions with conventional diesel combustion engines, economic competitiveness is only observed for passages of up to 2,500 km when including a carbon tax and forecasting optimistic battery developments.