Potentials and challenges of the fuel cell technology for ship applications. A comprehensive techno-economic and environmental assessment of maritime power system configurations

Abstract

The decarbonization of the global ship traffic is one of the industry’s greatest challenges for the next decades and will likely only be achieved with new, energy-efficient power technologies. To evaluate the performances of such technologies, a system modeling and optimization approach is introduced and tested, covering three elementary topics: shipboard solid oxide fuel cells (SOFCs), the benefits of decentralizing ship power systems, and the assessment of potential future power technologies and synthetic fuels. In the following, the analyses’ motivations, scopes, and derived conclusions are presented. SOFCs are a much-discussed technology with promising efficiency, fuel versatility, and few operating emissions. However, complex processes and high temperature levels inhibit their stand-alone dynamic operation. Therefore, the operability in a hybrid system is investigated, focusing on component configurations and evaluation approach corrections. It is demonstrated that moderate storage support satisfies the requirements for an uninterrupted ship operation. Depending on the load characteristics, energy-intensive and power-intensive storage applications with diverging challenges are identified. The analysis also emphasizes to treat degradation modeling with particular care, since technically optimal and cost-optimal design solutions differ meaningfully when assessing annual expenses. Decentralizing a power system with modular components in accordance with the load demand reduces both grid size and transmission losses, leading to a decrease of investment and operating costs. A cruise-ship-based case study considering variable installation locations and potential component failures is used to quantify these benefits. Transmission costs in a distributed system are reduced meaningfully with and without component failure consideration when compared to a central configuration. Also, minor modifications ensure the component redundancy requirements, resulting in comparably marginal extra expenses. Nowadays, numerous synthetic fuels are seen as candidates for future ship applications in combination with either combustion engines or fuel cells. To drive an ongoing technology discussion, performance indicators for envisioned system configurations are assessed in dependence on mission characteristics and critical price trends. Even if gaseous hydrogen is often considered not suitable for ship applications due to its low volumetric energy density, resulting little operating costs are accountable for its superior performance on short passages. For extended missions, fuel cells operating on methanol or ammonia surpass hydrogen economically.