expense of handling and storing it, disposing of ash and other solid wastes, and controlling emissions to the air. Only in very large installations, such as utility power plants and large industrial boilers, is coal today generally economic and environmentally suitable to burn. Domestic coal production capacity today exceeds economic demand, and this may well remain true until the end of the century.1
The health problems associated with coal affect both its production and its use. The health of underground miners presents complex and costly problems, for example, and is in need of better management; black lung is the notable instance. At the other end of the fuel cycle, the evolving state of air pollution regulations to deal with the emissions of coal combustion complicates planning for increased demand, and thus in turn inhibits investment in mines, transportation facilities, and coal-fired utility and industrial boilers.
The future is obscured also by a number of more speculative, less easily surmountable problems, which may result in further regulatory restrictions on the use of coal. Chief among these is the risk that before the middle of the next century, emissions of carbon dioxide, an unavoidable (and essentially uncontrollable) product of fossil fuel combustion, may produce such concentrations in the atmosphere as to produce large and virtually irreversible alterations in the world’s climate. (See chapter 9.) Also worrisome is the water-supply situation, which could limit synthetic fuel production or electricity generation unless large-scale and possibly expensive steps are taken to minimize water consumption and manage water supplies. This is already a limiting factor in some western locations, but the eastern coal regions may be approaching trouble too.
Coal-fired power plants burned nearly 70 percent of U.S. coal production in 1977, producing more than 45 percent of the nation’s electricity. Most of this was in large, centralized facilities with generating capacities of 300 megawatts (electric) (MWe) or more, designed to produce base-load power. (Smaller, less efficient oil- and gas-fired units and small, older coal units serve intermediate and peak loads.) Industry used one fifth of national production, slightly more than half of that in coke plants and the rest to produce steam and dry process heat. Almost all the rest (about 8 percent) was exported, mainly to make coke. Imports were less than 1 percent of U.S. production.
In the future, the market for coal can be widened. Development of efficient, relatively clean coal power cycles for use in smaller electricity-generating units decentralized to serve local loads, for example, will be attractive to industry and to utilities with power plant siting problems. Coal use for industrial process heat and chemical feedstocks will be harder to stimulate, especially in smaller installations, because of the expense and difficulty of handling the coal and the various wastes and emissions from