Enabling Battery- & Fuel Cell-based Hybrid Energy Systems for Ice-Class Research Vessels

Abstract

Hybrid energy systems are investigated as a viable alternative to conventional energy systems typically consisting of multiple diesel engines, on ice class vessels. Vessels bearing ice class notation experience significant disparities in load profiles between typical voyages and those involving occasional icy conditions. Ice class rules mandate considerably higher installed power than necessary for regular service, which can reduce the average operating efficiency of a conventional energy system. This paper demonstrates the performance of two hybrid energy system configurations on a 50-meter research vessel operating mainly in the Baltic Sea with ice class 1A. Ship resistance is calculated in open water and ice and characteristic time-based load profiles are generated for a selected route over three voyage conditions. The peak propulsion loads even in mild winter conditions with ice are observed to be over 4 times as high as open water operation in summer. Various hybrid energy system configurations including diesel gensets, fuel cells, and batteries are analyzed over three voyage conditions. Results indicate that a fuel cell-based energy system can yield up to 24.3% energy savings. Upto 13.8% energy savings can be achieved by modularizing the onboard genset installation, while battery hybridization enables optimal energy system operation over a wider range of voyages. Finally, it is shown that ice class capable energy system can perform as efficiently as a comparable downsized energy system when the genset installation is modularized, and even enable further fuel savings in the presence of fuel cells.