Water power has the advantages that its sources are not exhausted by use, and that the relatively greater initial cost of a hydro-electric plant is frequently more than compensated for by the saving in man power required and by the lower operating expense. However, the total amount of water power which can be developed on a commercial basis is rather closely limited, and much of the available power is so distributed geographically that it cannot be economically supplied to the industries which need it. Of the total water-power resources of the United States which have been estimated by the Geological Survey to be available for ultimate development, over 70 per cent is west of the Mississippi,—whereas over 70 per cent of the horse-power now installed in prime movers is east of the Mississippi. Electric power cannot at present be economically transmitted more than a few hundred miles. Furthermore, for many uses of coal, as in metallurgical and chemical processes which require the heat or reducing action of burning coal, and in its use as fuel for ships, hydro-electric power cannot be substituted. It seems clear that while the use of water power will increase, particularly as rising prices of coal make possible the development of new sites, it can never take the place of the mineral fuels in any large proportion.
For the immediate future, measures which have been suggested to extend the use of water power include: the more complete utilization of water powers already in use through more efficient machinery and methods; a certain degree of redistribution of industries, so that those requiring large amounts of power may be located in areas where water power is cheap and abundant; and the interconnection of hydro-electric plants so that their full capacity may be used. Some water powers which have been developed are not being fully utilized because the plants are not connected with distribution systems large enough to use all the power.
During the war the United States Geological Survey, in coöperation with the Fuel Administration and the War Industries Board, collected the information required to prepare maps showing the locations and relations of power stations and transmission lines throughout the country. This survey of the situation showed many possibilities, which had before been but vaguely realized, of interconnections which would increase the efficiency of the plants.
- Substitution of lower-grade coals—of bituminous for anthracite, and of low-grade bituminous for high-grade bituminous coals. Larger use of low-grade western coals. War and post-war conditions have shown Germany the way to a wide and effective use of its lignites. This has been accomplished by coöperation of the government and private interests. This vast improvement in methods of treatment and recovery of heating elements and by-products will doubtless have a widespread effect on utilization of lignites in other parts of the world.
- Substitution of alcohol and natural gas, oil, oil shales, peats, etc., as a source of power. This merely concentrates the conservation problem more largely on these minerals, in some of which, at least, it is already considerably more acute than in the case of coal; it is not a solution of the problem, but merely a shifting of emphasis.
Business conditions have limited private enterprise in this class of measures, but some progress has been made. More rapid introduction of these measures would require sacrifice of private interest and probably may be accomplished only by application of public power.