PUTNAM'S MAGAZINE VOL. VI AUGUST, 1909 NO. 5 "THE PEAK OF THE LOAD" WHAT IT MEANS TO LIGHT NEW YORK CITY AND By ARTHUR D. HOWDEN SMITH HEN the fog rolls over the city in successive damp, clinging waves, blotting out nextdoor neighbors, cutting off skyscrapers from the first story upward, making the paper on one's desk blurred and indistinct, the whole city, as with a single mind, makes for the electric-light switches and the gas-jets. The supply of natural light is definitely stopped for the time being, and artificial light is a pressing necessity. Meantime, in the engine-rooms and power-houses of the gas and electric companies, whistles are shrieking, bells clanging and men rushing back and forth in orderly haste. estimated in hundreds of thousands of horse-power, drowns out the rest of the world in a void of bewildering sound. But it is all done without confusion, in response to the pulling of a switch or the pressure of a button in some half-darkened little room, high up on the wall of the powerhouse, above the engines and turbines. "The peak of the load" has been reached-the point at which the highest energy is required to keep the divers lights and motors throughout the city running under full power. And when the phrase "highest energy" is used, it means the highest energy that the public can conceivably require in circumstances at all near the normalnot the highest energy of which the power-plants are capable. The gas and electric companies of New York City have never yet had their resources drained to the last drop. They always have something in reserve, held for utilization in the event of possible extreme emergencies. So vast is the potential energy Copyright, 1909, bv PUTNAM'S MONTHLY Co. All rights reserved. Great fires are stoked up; boilers strain under the additional pressure placed upon them; furnace doors swing back, revealing the ravenous maws within; the whirr and thunder of machinery, the power of which is stored away in the city's lighting and power plants that full realization of it is beyond the comprehension of the layman. To emphasize it broadly, New York has the most tremendous accumulation of horse-power in electricity and reserve supply of gas of all the cities of the world. In the gas-tanks dotted at intervals in the less thickly-populated sections are stored millions of feet of gas, while the Waterside Stations, Nos. I and 2, of the New York Edison Company, at the East River and Thirty-eighth Street, are capable of developing 250,000 horse-power. No other city has such a supply of current to call upon. It is almost as great as the horse-power at present developed by all the Niagara Falls powerhouses combined. Every day sees the "peak of the load"; it comes at the same time, with seasonal variations, at least once in the twenty-four hours. For this regular, scheduled increase of demand, the lighting plants are ready and waiting. It is only when some peculiar atmospheric condition, a sudden storm or thunder-shower, sweeps down upon the city, that they are taken by surprise; yet, because of the wonderful system which has been devised by the engineers in charge, even when they are surprised the city does not suffer by it. To be sure, the men in the enginerooms have to hustle somewhat faster than usual, but they know just what to do and how to do it in the shortest time. Hundreds of thousands of extra cubic feet of gas and kilowatts of electricity cannot be called for without some disarrangement of the previous state of affairs. It goes without saying that when many thousands of people, in the middle of the day, begin to consume gas and electricity, the makers of gas and electricity must feel the strain. How, then, are the lighting companies enabled to meet the demand? Some idea of the strain may be conveyed by the fact that inside. of a few minutes, one morning_last winter, the New York Edison Com pany jumped its energy 50,000 horsepower, an increase which would have sufficed to provide the city of Chicago for sixty-five minutes. Both the New York Edison Company and the Consolidated Gas Company have their own individual means of telling when it is necessary to increase their supplies of illuminants. The gas company has a mechanical system, which regulates itself automatically; the electric company relies more upon men, upon the human element. Scattered all over the city in apartment houses, stores and buildings of every description, the gas company has little instruments of a special design, gauges that register the exact pressure in the mains at that particular point. By law, this pressure at the street level should be from one to two and a half inches. When, by any contingency, this pressure is lowered, the gauge communicates the fact automatically to another gauge, hanging on the wall of one of the engine-houses, and rings a bell, warning a valve-man who is supposed to have his eye constantly on the needle. Immediately, the valve-man throws over a lever, which raises the pressure in the pipes by admitting gas from the storage-tanks. The entire time. consumed, from the registration of the falling of the pressure to the moment when the fresh supply of gas begins to flow into the mains, is generally not more than fifteen seconds. In other words, before the pressure in any main has lowered sufficiently to cause the slightest trouble, it has been raised; once the gas-engineers know that some part of the city is beginning to draw excessively upon them, they are able to meet the demand. This holds true, no matter whether the affected area is limited in size or includes the entire metropolitan district. It is simply a question of throwing open more gas-tanks. As often as not, too, when a call for extra gas is caused by a storm, the men in the engine-rooms have seen the storm coming and are prepared for it, in advance. |