Power plant design for all-electric ships considering the assessment of carbon intensity indicator

The design and management of a ship power system determine the amount of CO2 emitted during the ship operations. Recently, the International Maritime Organization has introduced the Carbon Intensity Indicator to limit the environmental impact of ships, pushing designers to define new solutions to reduce polluting emissions. The proposed methodology allows to estimate the environmental performances of a ship during the preliminary design phase, starting from the mission analysis. The tool simulates different power plant configurations, including diesel generators with different type of fuels, battery energy storage systems, fuel cells and hydrogen storage systems. Each source is modelled in the quasi-dynamic domain, where a set of selected state variables is taken into account. The load is derived from the ship mission profile through a stochastic process that considers the ship speed. Different power management strategies are tested to exploit the various resources while maximizing the operating condition requirements. A set of key performance indicators, such as the CO2 emissions, the weight, and volume of the equipment, allows to compare the various power plant configurations so that the preliminary design solution can be identified.