Fixed charges on initial investments form a large item—amounting often to about one-half the total cost—of hydro-electric power pro duction. As a rule the initial cost of hydro electric power development of small water powers is relatively high, often prohibitively so. This is especially likely to be the case sehere the investment includes the cost of transmission lines to market the output. Where a common distribution system is used, • small water power located near a transmission line may sometimes be developed, and its output turned upon the existing transmission line at the requisite phase, voltage and frequency. By thus operating in parallel,• as It is called, the construction of costly transmission lines for small water powers may be avoided in such cases, and a market found for their output. A further stimulus to the use of hydro-electric power in manufactur is afforded by the increased cost of coal subsequent to the Great World War.
In certain lines of manufacture, non-constant power can be used to advantage, as for ex ample in the grinding of wood pulp for printing paper. a process which consumes relatively lary quantities of power, commonly about 75 to 100 horse power per ton of product per day. Such industries afford a market for a large quantity of secondary power from hydro-electrt • stations.
Electrochemical industries require large and constantly increasing quantities of electric cur rent, which because of its cheapness compared with steam-generated current, is almost wholly produced by water power. Recently practicable methods of fixation of nitrogen from the at mosphere have been developed. The product is used in the manufacture of explosives, in other chemical industries, and especially as a means of the nitrification and consequent fertili zation or otherwise weak, worn-out or sterile soils. The demand for nitrogen compounds for agricultural fertilisers is enormous. Their production from the atmosphere requires the use of lave quantities of electric current. Under present conditions the fixation of nitrogen on a commercial basis for agricultural use can only be accomplished where hydro-electric power is available in large quantities at extremely low cost. This is obtained in some instances, in Scandinavia in particular, and affords a pros pective means of utilization of large water powers remote from commercial manufacturing centres.
At the present time, hydro-electric power de velopments range in size from those of a few horse power, supplying individual farms or small industries, to plants of 100,000 horse power or more, as at Keokuk, Cedar Rapids and Niagara Falls. The number of existing small water powers of 1,000 horse-power capac ity or less which are undeveloped greatly ex ceeds the number of large water powers, but by far the larger proportion of the total out put of hydro-electric current is produced by medium-sized plants of 1,000 to 20,000 horse power capacity, owing to the fact that these have been found to meet more generally the requirements of commercial feasibility for ex isting market conditions.
Hydro-electric power plants include so wide a variety of natural .conditions, types of equip ment and methods of development as to be difficult of typical illustration. They range in heads or falls utilized from a few feet to sev eral thousand feet — in voltage the current ranges from a few hundred volts to 150,000 volts—and in distance of transmission of the output the range is from zero to several hun dred miles. Certain features are, however, more
or less common to nearly all hydro-electric r developments, and these are illustrated following examples: Fig. 9 gives an ex ternal view, and also a view of the interior, of an hydro-electric power station of the Men gemor Company, Spam. This is a typical cas cade development, in that the fall is created by a dam which also provides pondag. e., and the power station is located immediately adjacent to the dam; Fig. 10 shows an external view, and also a view of one of the turbines and generators, of the hydro-electric power station of the city of Tokio. Japan. This is a high head development of the canal type. Water is brought to the top of the bluff from the Kat sura River, which has its source in Mount Fugi, by means of a canal, from which it is conveyed to the power station through steel pipe con duits. The turbines are of phosphor bronze, of 4,500 horse power each, and operate under a had of 315 feet.
Fig. 11 shows the power station and pipe lines supplying it used to generate electricity for the city of Bellinzona. Switzerland. This is a very high bead development, in which water wheels of the impulse, or Pelton type, are used, as shown in Fig. 11-b. Tice had or fall operat ing the water wheels is 1,132 feet. The water is brought down from the source of supply above the crest of the mountain through the small pipe line shown in the background in Fig. II-o.
Fig. 12 is a view of the interior of the Estacada plant of the Portland, Ore., Rail way Light and Power Company. Here a pair of spiral case Francis type turbines is connected to each of the generators.
The total mechanical power used in the United States is estimated at about 18000Q000 horse power. The larger proportion of this is used by railroad locomotives, and for a wide variety of miscellaneous purposes. The amount of power used directly in manufacturing was in 1(>09 as 11080,776 horse power. Of this only 1.8t12.573 horse power was produced directly by water power, and about an equal amount of hydro-electric power was purchased for manufacturing use. Central electric light and power stations produced at the same date about 7,500,000 horse power.
The developed water' "wer of the United State was estimated at 6,1 t 1,000 horse power in 1909. While the total water power of the streams of the United States exceeds 100,000,000 horse power, the larger proportion of this is not capable of profitable development at the present time.
Thus while it appears probable that there may be a material increase in the use of water power in the near future, and consequent reduction in the annual coal consumption, it must be expected that an enormous consumption of coal for power purposes will continue for many years. The total water-power resources of the world have been estimated at about 700,000,000 horse power. See Hiroammu:s.
Ball, Sir R. S.. 'Natural Sources of Power' (London 1915); La. E. A, and Rushmore, D. B., 'Hydro-electric Power Stations' (New York 1917); Lyndon.
'Hydro-electric Power' (2 vols., New York 1916) ; Mead, D. W., 'Water Power Engineer ing) (New York 1915) ; Taylor, W. T. and Braymer, D. H., 'American Hydro-electric Prac tice' (New York 1917) ; 'Report of the United States Commissioner of Corporations on Water Power Development in the United States' (Washington 1912).
Roam E. Horton, Consulting Hydraulic Engineer.