A HYDROGEN ECONOMY
For some time, people have envisioned an economy where the only source of energy was hydrogen. The idea may have originated in Jules Verne science fiction novel Mysterious Island. There, a shipwrecked engineer says that once they ran out of coal, they would use water as their source of energy. What he meant is the hydrogen in the water could provide the fuel as it did for the bacteria during the early history of Earth.
Hydrogen is a likely fuel. When burned in air, its end products are water and some nitrogen oxides. These oxides, which are potentially pollutants, can be reduced to negligible levels with catalytic heaters. So hydrogen would become the least polluting of all energy sources.
Its versatility makes it a likely candidate for a universal fuel. It has already demonstrated it can be used to fuel space exploration vehicles and to energize the fuel cell that generates their electricity. Hydrogen has also been used, in an experimental way, to power an automobile using a slightly modified conventional engine. Used this way, it is three times as efficient as gasoline. Hydrogen is also a heavyweight with regard to energy density.
Hydrogen's unavailability has prevented it from bestowing its benefits on society. The principal source of hydrogen is in water, where it is tightly bound to oxygen. Until recently, to liberate hydrogen required a great deal of energy, making it a less attractive option. But recent progress in generating electricity using renewable sources