As long as all factories had to be built by the side of streams having suitable water-power, the number and size of factories were always extremely limited. With the introduction of steam it became possible to build factories at mines, in forests, in fruit or grain regions, wherever the supply of raw material was plentiful, and to multiply factories of all kinds in cities near the markets for their product, or where labor was cheap and abundant. But power could only be used where it was developed, and the size of the power plant depended on the amount of business done by each individual user.
Now a new era of power has again enlarged the possibilities of manufacturing. By means of electricity the work, not only of factories, but also of the home and the farm may be done in any place where electricity can be installed. We must bear in mind that electricity is never a source of power, but is only the agent that carries power to the user. The source of all electric power is either steam or water, produced by water-wheels, turbines, steam-engines or gas-engines. The economical way to furnish electric power is to establish central power plants, and electricity may be conveyed from them for many miles. An electric railway, telegraph, or telephone system many miles in length is operated from a single power plant. Electric light and power are transmitted all over the largest cities. It is no longer necessary that a factory be of any specified size nor that it have any waste power. If it be within reach of the electrical current it may use as much or as little as is needed.
The cheapness of electric power must always depend on nearness to the source of supply or to the market. Until a short time ago it was customary to locate electric power-houses near the market, that is, in cities. But the benefits to be derived from having the electric plant near the source of power, so that the cost of production is greatly lessened, are becoming better recognized. This will make water-power increasingly valuable.
It is even now practicable to develop water-power, wherever located, for the production of electricity. Although the lowest grade coals are used for electric power at the mines yet they can now be used for still other purposes. Coal or other fuel once used can not be replaced, but when electricity is derived from water-power only energy otherwise wasted is used. This energy, if derived from water-power, is all added to our assets instead of being lost.
For many years the amount of power used for manufacturing and other purposes has doubled about once in ten years, and the steady pace kept by different lines of development shows how closely they are related. Our power, our forest cut, the use of our iron and other minerals, our coal and petroleum, the railroad earnings, freight and passenger traffic, and our agricultural products all double themselves every ten years. This means that in ten years we shall require twice as much power as now, but will have far less coal to use. This raises the question,—have we available water-power to conserve our coal supply? Let us see. It is estimated that we are now using 26,000,000 horse-power of energy derived from steam, 3,000,000 horse-power derived from water, and 800,000 from gas or oil, a total of 29,800,000 horse-power. It is also estimated that there is now running idly over dams, falls, and rapids 30,000,000 horse-power of energy. In other words, we are wasting every day enough water to run every factory and mill, and to turn every wheel, to move every electric car and to supply every electric light or power-station in the country.
The amount of water-power is gauged solely by the low-water stage of the stream. A river is considered to produce only as much power as it can furnish at its season of lowest water. At other times factories may be operated more actively, but usually most of the extra power is wasted during a large part of the year.
If these storm or flood waters can be stored in reservoirs, the stream-flow throughout the year can be made fairly uniform and the power possibilities greatly increased. The Geological Survey believes that by storing the flood waters and regulating the flow of the streams, the large rivers of the United States may be made to furnish 150,000,000 horse-power, enough, if it could be utilized, to supply every power need of our country for many years to come without using a ton of our coal, and without in any way decreasing the water.
Of course this can never be practicable. Much power will always be needed where no stream for power is available. But the lesson is plain that where water can be used it should be, both in order to save the coal and because it can be produced more cheaply. The 30,000,000 horse-power now available, if produced in our most modern electric plants, would require the burning of nearly 225,000,000 tons of coal, and if in the average plant run by steam-engines, more than 650,000,000 tons of coal, which is fifty per cent. more than all the coal that is now produced in this country. At three dollars per ton it would cost $2,000,000,000 a year to supply the coal to furnish the power that we might have, one might almost say, as a by-product from the improving of the rivers for navigation. The development of the water-power possibilities of the country is now going forward at a rapid rate, however.
Dams on the Susquehanna River will soon make 30,000 horse-power available, which could be increased to 200,000 by building storage reservoirs.
A dam just begun at the rapids of the Mississippi River at Keokuk, Iowa, will, when completed, furnish 200,000 horse-power. Niagara is producing 56,000 horse-power on the United States side. The Muscle Shoals Falls rapids in the Tennessee River is furnishing 188,000 horse-power. Illinois will greatly increase its possibilities for offering cheap power to factories, when the Lakes to Gulf Canal with 173,000,000 horse-power worth $12,750,000 yearly, and the Chicago Drainage or Sanitary Canal, which has nearly 60,000 horse-power, are complete. Both of these projects were undertaken by the state.