High Temperature Proton Exchange Membrane Fuel Cells (HT-PEMFC), rely mainly on the use of phosphoric acid-based membranes. HT-PEMFCs operate in the 150-250 °C range and, due to the higher temperature, have low sensitivity to fuel impurities. This allows them to run with LNG, methanol, diesel as primary fuels after an external reforming stage, as well as directly with hydrogen. The higher temperature also allows for better catalyst performance and better system heat rejection. HT-PEMFCs have demonstrated stack efficiencies of 50-60% slightly higher than a PEMFC. Moreover, the High temperature PEMFC is less susceptible to CO and sulphur toxicity and does not require a water management system compared to the PEMFC, but has a lower power density and cannot be started from cold. They have comparable, if not lower cost, to other fuel cell technologies for maritime applications. Their modular design allows for building blocks at the kW level (e.g. 50kW modules) that can be compiled for MW-scale systems. Remaining challenges include lifetime and relatively lower performance to other fuel cell technologies. http://www.dnvgl.com/maritime/publications/alternative-fuel-assessment-download.html).
Due to limited power output, this technology is likely to be used preferably for small and medium vessels, as currently proved by the ongoing demonstrations.