America's Energy Supply

To be presented at the 34.th Annual Convention of the American Institute of Electrical Engineers, Atlantic City, N. J., June 27, 1918. Copyright 1918. By Α. I. Ε. E. (Subject to final revision for the Transactions.) AMERICA'S ENERGY SUPPLY BY CHARLES P. STEINMETZ ABSTRACT OF PAPER The gist of the paper is to demonstrate that the economical utilization of the country's energy supply requires generating electric power wherever hydraulic or fuel energy is available, and collecting the power electrically, just as we distribute it electrically. In the first section a short review of the country's energy sup ply in fuel and water power is given, and it is shown that the total potential hydraulic energy of the country is about equal to the total utilized fuel energy. In the second section it is shown that the modern synchronous station is necessary for large hydraulic powers, but the solution of the problem of the economic development of the far more num erous smaller waterpowers is the adoption of the induction gener ator. However, the simplicity of the induction generator station results from the relegation of all the functions of excitation, regu lation and control to the main synchronous station. The eco nomic advantage of the induction generator station is, that its simplicity permits elimination of most of the hydraulic develop ment by using, instead of one large synchronous station, a number of induction generator stations and collecting their power elec trically. The third section considers the characteristics of the induction generator and the induction-generator station, and its method of operation, and discusses the condition of "dropping out of step of the induction generator" and its avoidance. In the appendix the corresponding problem is pointed out with reference to fuel power, showing that many millions of kilowatts of potential power are wasted by burning fuel and thereby degrad ing its energy, that could be recovered by interposing simple steam turbine induction generators between the boiler and the steam heating systems, and collecting their power electrically. It is shown that the value of the recovered power would be an appre ciable part of that of the fuel, and that organized and controlled by the central stations, this fuel power collection would improve the station load factor, give the advantages of the isolated plant without its disadvantages, and produce a saving of many millions of tons of coal. I. The Available Sources of Energy A. COAL HE only two sources of energy, which are so plentiful as to T come into consideration in supplying our modern industrial civilization, are coal, including oil, natural gas, etc., and water power. *Manuscript of this paper was received April 9, 1918. 591 592 STEINMETZ: AMERICA'S ENERGY SUPPLY [June 27 While it would be difficult to estimate the coal consumption directly, it is given fairly closely by the coal production, at least during the last decades, where wood as fuel had become negligible and export and import, besides more or less balancing each other, were small compared with the production. Coal has been mined since 1822, and in Fig. 1 is recorded the coal production of the United States, from the governmental reports. The annual production is marked by circles, the decennial average marked by crosses for every five years. Table I gives the decennial averages, in millions of tons per year. TABLE ι AVERAGE COAL PRODUCTION OF THE UNITED STATES (decennial average) Year Million tons Per cent increase per year per year 1825 0.11 30 0.32 22.4 35 0.83 19.7 40 1.92 17.0 45 4.00 14.5 50 7.46 10.45 55 10.8 8.35 60 16.6 8.72 65 25.9 9.22 70 40.2 8.58 75 56.8 7.42 80 82.2 7.95 85 122 6.80 90 160 5.40 95 206 5.75 1900 281 6.96 05 404 6.60 10 532 In Fig. 1 the logarithms of the coal production in tons are used as ordinates. With this scale, a straight line means a constant proportional increase, that is, the same percentage increase per year, and in the third column of Table I are given the average percentage increase of coal production per year. This Fig. 1 is extremely interesting by showing the great ir regularity of production from year to year, and at the same time a very great regularity over a long period of time. Since 1870 the average production may be represented by a straight line, the values lying irregularly above and below the line, which 1918] STEINMETZ: AMERICA'S ENERGY SUPPLY 593 represents an annual increase of 6.35 per cent and thus repre sents the average coal production1 C by the equation 00267 C = 45.3 X 10 Cy-i870) miHion tons or log C = 0.0267 (y-1870) + 7.656 where y = year. Before this time, from 1846 to 1884, the coal production could be represented by C = 7.26 X 10 0365 (y-i850) million tons or log C = 0.0365 (y-1850) + 6.861 representing an average annual increase of 8.78 per cent. 1820 1840 I860 1880. 1900 1920 FIG. 1—COAL PRODUCTION OF THE UNITED STATES It is startling to note how inappreciable, on the rising curve of coal production, is the effect of the most catastrophic political and industrial convulsions, such as the Civil War and the In dustrial panic of the early 90's; they are indistinguishable from the constantly recurring annual fluctuations. It means, that the curve is the result of economic laws, which are laws of nature. Extrapolating from the curve of Fig. 1, which is permissible, due to its regularity, gives 867 million tons as this year's coal consumption. As it is difficult to get a conception of such enormous amounts, I may be allowed to illustrate it. One of the great wonders of the world is the Chinese Wall, running 1. Soft coal and anthracite, and including oil reduced to coal by its fuel value. 594 STEIN METZ: AMERICA'S ENERGY SUPPLY [June 27 across the country for hundreds of miles, by means of which China unsuccessfully tried to protect its nothern frontier against invasion. Using the coal produced in one year as building material, we could with it build a wall like the Chinese Wall, all around the United States, following the Canadian and Mexican frontier, the Atlantic, Gulf and Pacific Coast, and with the chemical energy contained in the next year's coal production, we could lift this entire wall up into space, 200 miles high. Or, with the coal produced in one year used as building material, we could build 400 pyramids, larger than the largest pyramid of Egypt. It is interesting to note that 100 thousand tons of coal were produced in the United States in 1825; one million tons in 1836; 10 million tons in 1852 and 100 million tons in 1882. The pro duction will reach about 1000 million tons in 1920, and, if it con tinues to increase at the same rate, it would reach 10,000 million tons in 1958. Estimating the chemical energy of the average coal as a little above 7000 cal., the chemical energy of one ton of coal equals ap proximately the electrical energy of one kilowatt year (24 hour ser vice) . That is, one ton of coal is approximately equal in potential energy to one kilowatt-year. Thus the annual consumption of 867 millions of tons of coal represents, in energy, 867 million kilowatt-years. However, as the average efficiency of conversion of the chemical energy of fuel into electrical energy is probably about 10 per cent, the coal production, converted into electrical energy, would give about 87 million kilowatts. Assuming however, that only one half of the coal is used for power, at 10 per cent efficiency, the other half as fuel, for metal lurgical work etc., at efficiencies varying from 10 per cent to 80 per cent, with an average efficiency of 40 percent, then we get 217 million kilowatts (24 hour service) as the total utilized energy of our present annual coal production of 867 million tons. B. THE POTENTIAL WATER POWERS OF THE UNITED STATES Without considering the present limitation in the develop ment of water powers, which permits the use of only the largest and most concentrated powers, we may try to get a conception of the total amount of hydraulic energy which exists in our country, irrespective of whether means have yet been developed 1918] STEINMETZ: AMERICA'S ENERGY SUPPLY 595 or ever will be developed for its complete utilization. We there fore proceed to estimate the energy of the total rain fall. Superimposing the map of rain fall in the United States, upon the map of elevation, we divide the entire territory into sections by rain fall and elevation. This is done in Table II, for the part of our continent between 30 and 50 degrees northern latitude. TABLE π TOTAL POTENTIAL WATER POWER OF UNITED STATES In. Ft. Area Avg. Avg. Kg-m. Kg-m 2 rain elevation WÎUO12 X elevation rainfall per m ; total fall m. cm. l^X 1015X >10 >5000 0.54 2100 12.5 263 142 1000-5000 0.29 900 112 32.5 10-20 >5000 1.18 2100 37.5 787 930 1000-5000 1.96 900 338 660 20-30 1000-5000 0.32 900 62.5 563 183 100-1000 0.97 150 94 91 30-40 1000-5000 0.35 900 87.5 786 275 100-1000 1.40 150 131 184 40-60 1000-5000 0.27 900 125 1130 305 100-1000 1.03 150 188 194 Σ =2996 3000 As obviously only the general magnitude of the energy value is of interest, I have made only few sub-divisions: five of rain fall and four of elevation, as recorded in columns 1 and 2 of Table IP.

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