The electric truck conversation tends to focus on battery-electric vehicles (BEVs), especially in the context of local delivery. But there has been some activity in an alternate form of power, especially where heavier duty applications are concerned, that of hydrogen fuel cells.
In contrast with BEVs, fuel cell electric vehicles run on electricity produced in a hydrogen-powered fuel cell. The cell is composed of a series of proton exchange membrane electrodes that mix hydrogen with oxygen to generate electricity. Any of the energy that is not immediately used gets stored in a battery. Some energy also is produced by recapturing brake energy, which also gets stored in the battery.