Separating water into hydrogen gas and oxygen through electrical current, known as "electrolysis," is both the chief method behind green hydrogen energy, and expensive and inefficient.

Yet for long-haul trucking, steel manufacturing, and more, hydrogen could be the only input available in green energy's arsenal to replace petroleum products. The Swedish company SSAB is already making steel a bit greener by using hydrogen power to replace coal as a carbon input.

The Australian firm Hysata has changed the design of the major component to make the cost of pure hydrogen fuel competitive with fossil fuels by decreasing the heat and resistance generated through separating hydrogen.