II. EDISON, TESLA, WESTINGHOUSE, AND INSULL 
The Niagara River, only thirty miles long, connects Lake Erie with Lake Ontario. The rate of turnover in Lake Erie water is very high, and average flow rates through the Niagara and over the falls into Lake Ontario approach 100,000 cubic feet per second, making it the single greatest source of potential hydroelectric power in North America. Over several years in the mid-1890s, a massive power-producing development took shape around the falls, with the explicit intention of being, as a later commentator put it, the “pioneer hydro-electric system, forerunner of modern utility power service… the great step in the transition from the century of mechanical power to the century of electrical power.”5
The ancient Greeks were fascinated by electricity and magnetism, but European interest languished until the heroic age of sail spurred interest in the magnetic compass. A burst of development in the early nineteenth century—Volta, Ampère, Ohm, Faraday, and others—unveiled electricity’s potential as an energy source. By the 1830s, weak electrical pulses were sending telegraphs, and by the 1870s, European cities had begun to install electric outdoor arc-lighting.
Arc-light was produced when a high-voltage spark leaped between two filaments. The light was harsh, very hot, and often uncomfortably bright. Thomas Edison, the first time he saw an arc-light demonstration in 1878, decided it was a dead end. But he saw a huge opportunity if electrical power could be “subdivided” to power softer, cooler, lower-voltage lighting solutions for the home. When Edison was seized with an idea, he became a bulldozer. Within a week he had invented a working prototype of an incandescent light bulb. He immediately announced it in the press, organized public tours of his laboratory in Menlo Park, New Jersey, and in due course roped in J. P. Morgan to raise the development capital.
When his publicist’s hat was on, Edison could be reckless, and he announced that he would have a domestic electric lighting system in operation “within months.” Back in the lab, however, he set out methodically to create not just a long-lasting incandescent bulb but a whole congeries of improved generators, circuits, wiring systems, meters, and countless accessories—resistors, conductors, insulators, and so on. His system for generating remote electrical power and conducting it safely to the home was specified down to the last screw. He made two complete working models of the generating plant and the transmission system, and personally supervised every detail of its installation—manufacturing his own wire and insisting that it be encased in pipes and buried underground. To keep Morgan happy, he built a private lighting system for his new house, powered by a basement coal-fueled steam engine. The neighbors hated it, but Morgan was delighted, and the press duly swooned when the interior of the mansion sprang marvelously to life with bright, steady, easy-on-the-eyes lamps and ceiling fixtures.
Finally, in August of 1882, after six months of careful testing, the first Edison generating plant, at Pearl Street in lower Manhattan, went on line, with eighty-five customers using four hundred 110-volt DC lamps. Within two years Edison had more than five hundred customers with more than 10,000 lamps, and was making a small profit. As soon as Pearl Street stabilized, he began multiplying central power stations in Manhattan and opening Edison power companies in other states. The industry exploded. By 1890, there were a thousand central power stations in America, plus thousands more dedicated generators in office buildings and factories. Street railways were also electrifying rapidly. By then, Edison had serious competition, especially Westinghouse Electric and Thomson-Houston.
The Niagara project, however, completely changed the profile of the industry. Rather unexpectedly, it turned into a shoot-out between Edison-style DC (direct current) technology—dominated by General Electric—and AC (alternating current) technology owned by Westinghouse. George Westinghouse, one of America’s greatest entrepreneurs, and one of the few with a good grasp of science, had bought up most of the important AC patents, especially those of the eccentric Serbian genius, Nikola Tesla. AC was still a relatively untested technology, but its theoretical advantages over DC for a national system were hard to overlook. At the currents required for residential service, DC power could be transmitted only about a half mile, so electrifying a major city required honeycombing it with unsightly coal-fed steam generator plants. Westinghouse had lit the 1893 Chicago World’s Fair with AC, but since it was only a local system, it did not settle the critical question of long-distance transmission. The assurances that it would work came almost entirely from the mathematicians.*
The Niagara chief executive, Edward Dean Adams, and his chief engineer, Coleman Sellers Jr., made the decision to go with AC, and carried a majority of the directors, despite dissents from some of the experts. Adams, a small man with a large drooping mustache, was a banker and a lawyer who had gotten the job on Morgan’s insistence—Morgan had been impressed by his performance in several complex railroad restructurings. Sellers, in his sixties, semi-retired, with an elegant white Van Dyke beard, was one of the country’s premier engineers. Westinghouse’s willingness to bet his company on AC was also a big factor in the final decision.
But the three must have endured night sweats at the sheer dare-deviltry of their undertaking. The major elements of the system were all constructed in parallel and were almost all started before major design decisions had been settled. The tailrace tunnel, the huge underground pipe that carried the discharged plant water back to the river, was started well before the power technology was sorted out. As excavation proceeded, the tunnel’s specifications were changed several times, and it finally emerged as a mile-and-a-quarter-long, 24-foot-diameter monster, bigger than any high-pressure tunnel in the world. The beating heart of the complex was housed in a 200-foot long Stanford White limestone building about a mile from the falls. It comprised ten 5,000 horsepower (hp) alternators, or AC generators, 50,000 hp in all, each connected by a shaft to a water turbine 140 feet below. Beneath the powerhouse, at the top of each shaft, a seven-foot-six-inch-diameter pipe delivered free-falling river water to drive the turbine. The arrangement “far exceeded in power and speed and head of water any then in existence.”6