Hydroelectric power in the United States

Hydroelectricity is, as of 2019, the second-largest renewable source of energy in both generation and nominal capacity (behind wind power) in the United States.

[2] According to the International Hydropower Association, the United States is the 3rd largest producer of hydroelectric power in the world in 2021 after Brazil and China.

The earliest hydroelectric power generation in the U.S. was utilized for lighting and employed the better understood direct current (DC) system to provide the electrical flow.

It did not flow far however, with ten miles being the system's limit; solving electricity's transmission problems would come later and be the greatest incentive to the new hydroelectric water-power developments.

[7] The first DC powerhouse was in Grand Rapids, Michigan, where the water turbine at the Wolverine Chair factory was attached to a dynamo using a mechanical belt drive to illuminate sixteen street lights.

In 1881, also using DC for lighting at Niagara Falls, Jacob F. Schoellkopf diverted part of the output from his waterwheel-powered flour mills to drive one of Charles Brush's improved generators to provide nighttime illumination for the tourists.

Multiple permanent hydropower stations still exist on both the American and Canadian sides of the Falls, including the Robert Moses Niagara Power Plant, the third largest in the United States.

The need to provide rural development in the early 20th century was often coupled to the availability of electric power and led to large-scale projects like the Tennessee Valley Authority which created numerous dams and, sometimes controversially, flooded large areas.

In the 1930s, the need for power in the Southwest led to the building of the largest concrete construction in the world at that time, the Hoover Dam.

A project was proposed and run by the Snohomish County PUD in Washington but was ended when trouble was encountered obtaining enough funding.

There are over 80,000 Non-powered dams (NPDs) in the United States that could add 12 GW of nameplate capacity or 45 terawatt hours (TWh) per year.