The hydrogen fuel cell electric vehicles (FCEVs) convert the chemical energy of hydrogen and air into electricity. FCEV are hybrid vehicles, as they are hydrogen dominant and only use a small battery compared to battery electric vehicles (at least by a factor of 10). By exploiting the higher gravimetric energy density of hydrogen, FCEVs can offer a higher range than BEVs, including long-range, fast refuelling, and zero tail-pipe emissions (they only emit water). However, their continuing deployment faces multiple technical and economic challenges, including safety of hydrogen handling (refuelling, residual leakage), lack of sufficient refuelling infrastructure, on-board hydrogen storage (see the dedicated entry below) and the high cost of the fuel cell stack (the electrochemical reaction inside the stack requires a proton exchange membrane (PEM) coated with a platinum-based catalyst, a costly material) and system. Costs of the fuel cell stack and system are expected to decline significantly with economies of scale.
For FCEVs to be competitive with other powertrain technologies, hydrogen must be delivered to hydrogen refuelling stations at prices that bring per kilometre costs into the same range as conventional ICEs, or of battery electric vehicles powered by grid electricity. This will require further cost reductions in technologies for low- and zero-carbon hydrogen production technologies (e.g., SMR with CCS, renewable electricity generation such as wind and solar coupled to electrolysers), as well as in hydrogen transmission and distribution networks and in hydrogen refueling stations (HRS). Fuel cells needs also to meet the high durability (e.g., 25,000-hour lifetimes) and performance requirements for trucks.