H/sub 2/O: the limiting reactant in the energy equation

According to a study supported by the U.S. Department of the Interior, water is the key component of any energy system; domestic energy self-sufficiency can only be attained by the use of coal in the intermediate term of 30 to 50 years; the increased reliance on coal will strain available water supplies; 30 to 40% of the original heat content of coal is lost during the conversion to liquid or gaseous fuels; the primary coal-derived synthetic fuels will be SNG; sulfur-free low-Btu gas, solvent refined coal, low-sulfur liquid boiler fuels, and liquid hydrocarbon fuels including gasoline, diesel fuel, and naphtha; and 100 SNG plants, each producing 250 million cu ft/day SNG, would supply only 5% of the projected U.S. energy demand in 2000 (based on historical growth rates). The water requirements for each plant of this capacity will total 19,600 to 48,900 acre ft/yr depending on the quantity of makeup cooling water required (3 to 7%) and the type of coal used (bituminous, sub-bituminous, of lignite).