A Proton Exchange Membrane & Solid Oxide Fuel Cell comparison

Abstract

With increasing pollution to air from the shipping industry and future stricter regulation concerning marine fuels, new ways are required to power ships. Fuel cells could be a solution to decrease emissions that ships contribute with. They have higher efficiency and can be run on cleaner fuels. In this study, two fuel cell techniques are compared: PEMFC (proton exchange membrane fuel cell) and SOFC (solid oxide fuel cell). The technical performance and cost of the fuel cells were assessed based on a literature review combined with data from consultations with industry representatives. Within the field there is plenty of literature, articles and reports. Fuel cost calculations are also included in the study where present and possible future fuels are included. In the study one can see that both PEMFC and SOFC have higher efficiency than combustion engines. If hydrogen is used as fuel the only emission is water. Both techniques have comparable electrical efficiency. PEMFC is compact and handles generally load variations better. SOFC is not as compact and works at higher temperatures than PEMFC. The SOFC can be combined with a gas turbine increasing its efficiency. If waste heat recovery is used its efficiency is further increased. PEMFC has a lower capex compared to SOFC but SOFC can utilize natural gas which is cheaper than hydrogen. PEMFC has the highest power to volume ratio, however it runs on hydrogen which has low volumetric density compared to tradition marine fuels. With this, new challenges will arise at same time as fuel cells will offer a sustainable choice.