Hydrogen Economy (cont)

There are two primary uses for hydrogen today. About half is used to produce ammonia (NH3) via the Haber process, which is then used directly or indirectly as fertilizer. Because both the world population and the intensive agriculture used to support it are growing, ammonia demand is growing. The other half of current hydrogen production is used to convert heavy petroleum sources into lighter fractions suitable for use as fuels. This latter process is known as hydrocracking. Hydrocracking represents an even larger growth area, since rising oil prices encourage oil companies to extract poorer source material, such as tar sands and oil shale. The scale economies inherent in large scale oil refining and fertilizer manufacture make possible on-site production and "captive" use. Smaller quantities of "merchant" hydrogen are manufactured and delivered to end users as well.

If energy for hydrogen production were available (from wind, solar or nuclear power), use of the substance for hydrocarbon synfuel production could expand captive use of hydrogen by a factor of 5 to 10. Present U.S. use of hydrogen for hydrocracking is roughly 4 million metric tons per year (MMT/yr). It is estimated that 37.7 MMT/yr of hydrogen would be sufficient to convert enough domestic coal to liquid fuels to end U.S. dependence on foreign oil importation [3], and less than half this figure to end dependence on Middle East oil. Coal liquefaction would present significantly worse emissions of carbon dioxide than does the current system of burning fossil petroleum, but it would eliminate the political and economic vulnerabilities inherent in oil importation.