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 ship-
wrecked 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 poten-
tially 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 hydro-
gen required a great deal of energy, making it a less attractive option.
But recent progress in generating electricity using renewable sources

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