For transportation, two types of fuel cells come to mind: PEMs or SOFCs. A third variety, DCFCs, may have a place in transport systems, and may have advantages in using “dirty” fuels. PEM (Polymer Electrolyte Membrane – or Proton Exchange Membrane) cells use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum or platinum alloy catalyst. They need only hydrogen, oxygen from the air, and water to operate. They are typically fueled with pure hydrogen supplied from storage tanks or reformers. SOFCs (Solid Oxide Fuel Cells) use a hard, non-porous ceramic compound as the electrolyte. SOFCs are around 60% efficient at converting fuel to electricity. In applications designed to capture and utilize the system’s waste heat (co-generation), overall fuel use efficiencies could top 85%. They operate at high temperatures (1,000° C or 1,830° F). Both PEMs and SOFCs use hydrogen, which must be extremely pure and is therefore often produced at high costs. What if a …