Hydroelectric Power

Water: Science and Issues, (2003) by William Arthur Atkins

Hydroelectric Power

The damming of streams and rivers has been an integral part of human civilization from its early history. Controversy paralleled this use because impounding and diverting water for upstream users affects those who live downstream, and also modifies the local habitats of plants and animals. Dams are built to control floods, improve navigation, provide a drinking-water supply, create or enhance recreational opportunties, and provide water for irrigation and other agricultural uses. A small percentage of dams (less than 3 percent in the United States) are used to generate power.

Waterpower was the impetus that powered manufacturers who were building a growing nation during the U.S. Industrial Revolution of the Hydropower generates about 24 percent of the world's and 12 percent of the United States' electricity. Shown here are the massive turbines inside a hydropower plant along Washington state's Spokane River. nineteenth century. Waterwheels used the power of river water flowing downstream to turn machinery. Water continued to produce the largest part of industrial power until after the Civil War (from 1861 to 1865) when it diminished in importance. Yet waterpower would soon experience a rebirth in the form of hydroelectric power. The modern terms "hydroelectric power" and "hydropower" generally have the same meaning.

Coming of Age

At the beginning of the twentieth century, hydroelectric power in the United States came of age with three events: the development of the electric generator; improvements in the hydraulic turbine; and a growing demand for electricity. The first commercial hydroelectric power plant was built in 1882 on the Fox River in Appleton, Wisconsin, in order to provide 12.5 kilowatts of power to light two paper mills and a residence. Paper manufacturer H. F. Rogers developed the plant after seeing Thomas Edison's plans for an electricity power station in New York.

Early Twentieth Century.

Commercial power companies soon began to install a large number of small hydroelectric plants in mountainous regions near metropolitan areas. By 1920, hydroelectric plants accounted for 40 percent of the electric power produced in the United States.

The creation of the Federal Power Commission in 1920 increased development of hydroelectric power plants. The development of larger and more cost-efficient power plants showed that monetary support by the federal government was necessary for such hydroelectric plants to compete effectively with other power-generating plants. Then in 1933 the government saw that besides power production, hydroelectric power plants could also be effectively used for flood control, navigation, and irrigation. As a result, the government created the Tennessee Valley Authority in the southeastern United States to develop large-scale waterpower projects. In the Pacific Northwest, the Bonneville Power Administration, created in 1937, similarly focused on electrifying farms and small communities with public power.

The Lower Granite Dam on the Snake River in Washington state is a "run-of-the-river" hydroelectric dam operated by the U.S. Army Corps of Engineers. The Bonneville Power Administration, a federal agency located in the Pacific Northwest, markets wholesale electricity and transmission from Lower Granite and twenty-nine other federal dams. From left to right is the dam's earthen embankment; locks; the spillway; and the powerhouse.

Today.

Hydroelectric power plants generally range in size from several hundred kilowatts to several hundred megawatts , but a few enormous plants have capacities near 10,000 megawatts in order to supply electricity to millions of people. According to the National Renewable Energy Laboratory, world hydroelectric power plants have a combined capacity of 675,000 megawatts that produces over 2.3 trillion kilowatt-hours of electricity each year; supplying 24 percent of the world's electricity to more than 1 billion customers.

In many countries, hydroelectric power provides nearly all of the electrical power. In 1998, the hydroelectric plants of Norway and the Democratic Republic of the Congo (formerly Zaire) provided 99 percent of each country's power; and hydroelectric plants in Brazil provided 91 percent of total used electricity.

In the United States, more than 2,000 hydropower plants make hydro-electric power the country's largest renewable energy source (at 49 percent). The United States increased its hydroelectric power generation from about 16 billion kilowatt-hours in 1920 to nearly 306 billion kilowatt-hours in 1999. It runs a close second to Canada in the total amount of hydroelectric power produced worldwide. However, only 8 percent of the total U.S. electrical power was generated by hydroelectric power plants in 1999.

The largest U.S. hydropower plant is the 6,800-megawatt Grand Coulee power station on the Columbia River in Washington State. Completed in 1942, the Grand Coulee today is one of the world's largest hydropower plants, behind the 13,320-megawatt Itaipu hydroelectric plant on the Paraná River between Paraguay and Brazil. *