Niagara Falls Power Plant (1895): Tesla's AC Harnesses the Falls

The Adams Power Plant at Niagara Falls, New York, was the first large-scale hydroelectric station to generate alternating current (AC) for distribution to industry and cities. It began delivering power in August 1895 and sent electricity to Buffalo in November 1896, proving that the AC system built on Nikola Tesla’s patents and manufactured by Westinghouse could power a modern economy.

Background: harnessing the falls

For decades engineers and investors had dreamed of tapping the enormous energy of Niagara Falls. Small mills used water from a hydraulic canal, but the problem was how to use the power at scale and send it beyond the immediate area.

The falls were also a matter of public concern. From the 1870s campaigners, including the landscape architect Frederick Law Olmsted, worked to protect the scenery from mills and tourist traps, and in 1885 New York State created the Niagara Reservation, buying back land beside the falls from private owners. Any large power scheme therefore had to take water from the river upstream without spoiling the view of the falls themselves.

In 1886 the engineer Thomas Evershed proposed a plan to divert water from the Niagara River above the falls, run it through turbines and discharge it through a tunnel beneath the town. The Cataract Construction Company was formed in 1889 to carry it out, with backing from New York financiers including J. P. Morgan and John Jacob Astor IV. Its president was the banker Edward Dean Adams.

The tailrace tunnel, roughly 2 km (about 1.3 miles) long, was dug under the town of Niagara Falls between 1890 and 1893. The water would fall through vertical shafts to turbines at the bottom and flow out to the river below the falls.

AC or DC?

The bigger question was how to turn the water’s energy into useful power. In 1890 the company set up the International Niagara Commission in London, chaired by the eminent physicist Lord Kelvin, and invited proposals from around the world. Options included compressed air, cable systems, direct current (DC) and alternating current (AC).

The choice came at the height of the War of the Currents, the rivalry between Thomas Edison’s DC system and the AC system of George Westinghouse. Kelvin himself initially favoured DC. However, AC voltages could be raised with transformers for long-distance transmission and lowered again for use, which DC could not do economically at the time.

The commission received a number of proposals but adopted none of them outright. Meanwhile, practical experience with AC was growing. Westinghouse lit the 1893 World’s Columbian Exposition in Chicago with alternating current, a highly visible demonstration of the system’s reliability. Coleman Sellers, chief engineer of the Cataract Construction Company, and the British consulting engineer George Forbes were among those who shaped the final design at Niagara.

After much study the company chose a polyphase AC system. In October 1893 Westinghouse won the contract for the generators, based on the polyphase motor and generator patents of Nikola Tesla that Westinghouse had licensed in 1888. General Electric later won contracts for transformers and the transmission line to Buffalo.

Building Power House No. 1

The powerhouse was designed in stone by the architects McKim, Mead & White, with Stanford White leading the design. Inside, turbines designed by the Swiss firm Faesch & Piccard drove vertical shafts connected to huge generators above.

Each of the first Westinghouse generators produced about 5,000 horsepower of two-phase alternating current at 25 cycles per second and 2,200 volts, the largest machines of their kind at the time. The first unit went into service in 1895, and on 26 August 1895 power was delivered to the Pittsburgh Reduction Company, which used it to make aluminium. By the end of the decade Power House No. 1 held ten generators.

Power for Buffalo

The real test was transmission. Just after midnight on 16 November 1896, current stepped up to 11,000 volts was sent about 26 miles (42 km) to Buffalo, where it first ran the city’s streetcars. In January 1897 Buffalo celebrated with a banquet at which Tesla spoke.

Cheap Niagara power attracted energy-hungry electrochemical and electrometallurgical industries, including aluminium, carborundum and other abrasives, and chemical works. A second powerhouse, completed in 1904, brought the total to 21 generators.

Industry and the falls

Niagara power transformed the local economy. The Pittsburgh Reduction Company, later the Aluminum Company of America (Alcoa), built works beside the plant because the new electrolytic process for making aluminium needed vast amounts of cheap electricity. Edward Goodrich Acheson moved his production of carborundum, an artificial abrasive, to Niagara Falls in the mid-1890s, and firms making chemicals such as caustic soda and chlorine followed. Within a few years Niagara Falls, New York, had become one of the leading electrochemical centres in the world.

Power companies were soon built on the Canadian side as well. As more water was diverted, concern grew that the falls themselves might be diminished. The Burton Act of 1906 in the United States and the Boundary Waters Treaty of 1909 between the United States and Britain, acting for Canada, set limits on how much water could be taken, a balance between scenery and power that later agreements continued to manage.

Key people

• Nikola Tesla, the Serbian-American inventor whose polyphase AC patents formed the basis of the system.
• George Westinghouse, whose company manufactured the generators and championed AC.
• Edward Dean Adams, president of the Cataract Construction Company, after whom the plant was named.
• Lord Kelvin, chairman of the International Niagara Commission, who later accepted the AC choice.

Consequences and legacy

The success at Niagara settled the War of the Currents in favour of AC for large power systems. Alternating current became the standard for electricity generation and distribution around the world, building on the principles of Faraday’s electromagnetic induction and replacing the local DC networks pioneered after Edison’s light bulb.

The Adams plant was closed in 1961, when the much larger Robert Moses Niagara Power Plant replaced it. The powerhouses were demolished, but the stone Transformer House survives and is a National Historic Landmark. Statues of Tesla stand on both the American and Canadian sides of the falls.

Myths and facts

• Myth: Tesla designed and built the Niagara plant himself. Fact: His patents underpinned the system, but the plant was designed by teams of engineers at Westinghouse, General Electric and the power company.
• Myth: Niagara was the first AC power station. Fact: Smaller AC plants already existed, such as those in Colorado and Germany in the early 1890s; Niagara was the first on such a large scale.

Timeline

• 1889: The Cataract Construction Company is formed.
• 1890: The International Niagara Commission meets in London under Lord Kelvin.
• 1893, October: Westinghouse wins the contract for polyphase AC generators.
• 1895, 26 August: The plant begins delivering power to the Pittsburgh Reduction Company.
• 1896, 16 November: Power is transmitted to Buffalo.
• 1897, January: Buffalo celebrates with a banquet addressed by Tesla.
• 1904: Power House No. 2 is completed.
• 1961: The Adams plant is closed.

Why it matters

The Adams Power Plant showed that electricity could be generated on a vast scale and sent long distances, the model for every modern power grid. It made Niagara Falls a symbol of the electrical age and secured alternating current as the world’s standard.