hydroelectricity

(electricity) Electric power produced by hydroelectric generators. Also known as hydropower.

Electricity generated from the energy of running water, usually water falling over a dam.

• Only a small proportion of the electricity in the United States is produced by hydroelectric power.

Energy produced as generators are turned by the power of running water. The necessary conditions are a constant supply of water from rivers and lakes, steep slopes to aid the fall of water, and stable geological conditions for the construction of dams.

However, recent research indicates that the construction of dams may trigger off earth movements. The energy generated is a function of the height of falling water as well as of the mass of water concerned. A high proportion of the energy is converted into electricity.

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A hydro station generates power by the controlled release of water from the reservoir of a dammed … (credit: © Merriam-Webster Inc.)

Electricity produced from generators driven by water turbines that convert the energy in falling or fast-flowing water to mechanical energy. Water at a higher elevation flows downward through large pipes or tunnels (penstocks). The falling water rotates turbines, which drive the generators, which convert the turbines' mechanical energy into electricity. The advantages of hydroelectric power over such other sources as fossil fuels and nuclear fission are that it is continually renewable and produces no pollution. Norway, Sweden, Canada, and Switzerland rely heavily on hydroelectricity because they have industrialized areas close to mountainous regions with heavy rainfall. The U.S., Russia, China, India, and Brazil get a much smaller proportion of their electric power from hydroelectric generation. See also tidal power.

For more information on hydroelectric power, visit Britannica.com.

The capability to produce and deliver electricity for widespread consumption was one of the most important factors in the surge of American economic influence and wealth in the late nineteenth and early twentieth centuries. Hydroelectric power, among the first and simplest of the technologies that generated electricity, was initially developed using low dams of rock, timber, or granite block construction to collect water from rainfall and surface runoff into a reservoir. The water was funneled into a pipe (or pen-stock) and directed to a waterwheel (or turbine) where the force of the falling water on the turbine blades rotated the turbine and its main shaft. This shaft was connected to a generator, and the rotating generator produced electricity. One gallon (about 3.8 liters) of water falling 100 feet (about 30 meters) each second produced slightly more than 1,000 watts (or one kilowatt) of electricity, enough to power ten 100-watt light bulbs or a typical hairdryer.

There are now three types of hydroelectric installations: storage, run-of-river, and pumped-storage facilities. Storage facilities use a dam to capture water in a reservoir. This stored water is released from the reservoir through turbines at the rate required to meet changing electricity needs or other needs such as flood control, fish passage, irrigation, navigation, and recreation. Run-of-river facilities use only the natural flow of the river to operate the turbine. If the conditions are right, this type of project can be constructed without a dam or with a low diversion structure to direct water from the stream channel into a penstock. Pumped-storage facilities, an innovation of the 1950s, have specially designed turbines. These turbines have the ability to generate electricity the conventional way when water is delivered through penstocks to the turbines from a reservoir. They can also be reversed and used as pumps to lift water from the powerhouse back up into the reservoir where the water is stored for later use. During the daytime when electricity demand suddenly increases, the gates of the pumped-storage facility are opened and stored water is released from the reservoir to generate and quickly deliver electricity to meet the demand. At night when electricity demand is lowest and there is excess electricity available from coal or nuclear electricity generating facilities the turbines are reversed and pump water back into the reservoir. Operating in this manner, a pumped-storage facility improves the operating efficiency of all power plants within an electric system. Hydroelectric developments provide unique benefits not available with other electricity generating technologies. They do not contribute to air pollution, acid rain, or ozone depletion, and do not produce toxic wastes. As a part of normal operations many hydroelectric facilities also provide flood control, water supply for drinking and irrigation, and recreational opportunities such as fishing, swimming, water-skiing, picnicking, camping, rafting, boating, and sightseeing.

Origins of the Hydroelectric Industry 1880–1930

Hydroelectric power technology was slow to develop during the first ten years of the hydroelectric era (1880–1889) due to the limitations of direct current electricity technology. Some pioneering hydropower developments using direct current technology are described below.

The Grand Rapids Electric Light and Power Company in Michigan connected a dynamo to a waterwheel for the Wolverine Chair Factory in July 1880 and this installation powered 16 brush-arc lamps.

A dynamo was connected to a hydropower turbine at Niagara Falls in 1881 to power the arc lamps for the city streets.

The first hydropower facility in the western United States was completed in San Bernardino, California, in 1887.

By 1889 there were about 200 small electric generating facilities in the United States that used water for some or all of their electricity production.

The potential for increasing hydroelectric development was dramatically enhanced in 1889 when alternating current technology was introduced, enabling electricity to be conveyed economically over long distances.

The next 30 years of the modern era of hydroelectric development, 1890 to 1920, began with the construction of individual hydroelectric facilities by towns, cities, cooperatives, and private manufacturing companies for their own specific needs, and ended with the organization of the first utility system in the country. Cities and towns used hydroelectric facilities to provide electricity for trolley systems, streetlights, and individual customers. Cooperatives brought together groups of individuals and businesses to establish a customer pool that could finance and construct hydroelectric facilities for their own needs. Hundreds of small factories and paper mills in New England, the South, and throughout the Midwest constructed hydroelectric facilities for their own specific industrial use. Just prior to World War I, Southern Power Company purchased a large number of hydroelectric facilities from cites, towns, cooperatives, and factories, and consolidated them into the first regional utility power system in the United States. By 1920 hydroelectric facilities supplied 25 percent of the electricity used in the United States.

The hydroelectric industry matured between 1920 and 1930. During this period, electrical grid systems expanded, reaching more customers who were eager to receive and use electricity. Industrial production grew to satisfy the demand for consumer goods, requiring additional electricity. To meet the increasing demand, town and city electrical systems and regional utility systems grew in number and size throughout the more populated areas of the country. By 1930 hydroelectric facilities were delivering almost 30 percent of the nation's electricity needs.

The Hydroelectric Industry Prospers 1930–1980

The hydroelectric industry prospered from 1930 to 1980 for a number of reasons. Considerable federal funding was provided from 1930 through the 1960s for the construction of large federal dams and hydroelectric facilities. A major percentage of the massive increases in electricity required for wartime production during the 1940s was met by the construction of a sizable number of hydroelectric facilities; and to meet escalating electricity needs in response to the dramatic expansion of consumer demand and industrial production throughout the decades of the 1950s, 1960s, and 1970s, many new electric generating facilities, including hydroelectric developments, were constructed.

In the 1930s, major federal funding for new dam and hydroelectric facility development was allocated for three locations: the Tennessee River under authority of the Tennessee Valley Authority (TVA), the Colorado River under authority of the U.S. Bureau of Reclamation (Bureau), and the Columbia River under authority of the Bureau and the U.S. Army Corps of Engineers (COE). The TVA was established during the Great Depression in 1933 to develop multiple-use water resource projects in the Tennessee River system and spur economic development in Tennessee. It began construction in 1935 on a series of dams with hydroelectric facilities, which included almost 30 dams by the time the system was completed in 1956. Most of the TVA growth took place during World War II when the electrical demand necessary to develop the atomic bomb in the region surged by 600 percent between 1939 and 1945.

The Bureau, established in 1902 to promote the development of the western United States through the construction of federal irrigation dams, completed the world famous Hoover Dam on the Colorado River in 1936. Hoover Dam, which opened three years ahead of schedule, was a public works project intended to relieve unemployment during the Great Depression and provide critical electricity to meet the growing needs of the City of Los Angeles, California. At the same time, the Bureau and COE undertook the development of the great dams on the Columbia River in the northwestern United States. Within six years of the initial operation of Hoover, the Bureau completed Grand Coulee Dam on the Columbia

River, still the largest dam in the northwestern United States. During the mid-1940s, Grand Coulee supplied the electricity needed to produce planes and other war material to support U.S. victory in World War II. Bonneville Dam, completed in 1938 by the COE and also located on the Columbia River, was a public works project to help relieve regional unemployment during the Great Depression. Like Grand Couleee, Bonneville also supplied critical electricity in support of World War II production efforts. In 1940 hydroelectric plants supplied more than 35 percent of the nation's electricity.

Grand Coulee and Bonneville, along with the other large hydroelectric projects constructed in the northwest region from the 1940s through the 1960s, supplied between 80 and 90 percent of the electricity consumed in the states of Washington and Oregon by 1980. However, the portion of the nation's electricity supplied by hydroelectric facilities had declined to 12 percent. Federal support for constructing dams where a hydroelectric plant could be included was declining and initial steps were being taken to alter the primary mission of the Bureau and COE from developing new projects to operating and maintaining existing facilities.

Regulation of the Hydroelectric Industry 1899–1986

Hydroelectric power development has always been closely linked to political influences. Federal recognition of the necessity to control development on the nation's waterways began with the passage of the Rivers and Harbors Act in 1899, less than twenty years after the appearance of the first hydroelectric facility. The rapid expansion of interest in natural and water resources led to the creation of the Inland Waterways Commission in 1907. This Commission issued a report advocating a national policy to regulate development on streams or rivers crossing public lands. A White House Natural Resources Conference the following year proposed increased development of the nation's hydroelectric resources. As a result, the Federal Water Power Act (FWPA) was passed in 1920, establishing the Federal Power Commission (FPC) with the authority to issue licenses for non-federal hydroelectric development on public lands and waterways. Recognizing that the FWPA did not extend to all waterways, Congress enacted the Federal Power Act (FPA) in 1935 to amend the FWPA. The FPA extended the FPC's authority to all hydroelectric projects built by utilities engaged in interstate commerce. The FPA also required that the effects of a project on other natural resources be considered along with the electricity to be produced by the project.

From 1940 to 1980, twenty-two federal laws were passed that affect the hydroelectric licensing decisions of the FPC (renamed the Federal Energy Regulatory Commission [FERC] in 1977). Included among these laws are the Fish and Wildlife Coordination Act, Wilderness Act, National Historic Preservation Act, Wild and Scenic Rivers Act, National Environmental Policy Act, Endangered Species Act, Federal Land Policy and Management Act, Soil and Water Resources Conservation Act, Public Utility Regulatory Policies Act, and Energy Security Act. The enactment of these laws coincided with increasing concerns that negative environmental consequences result from dam construction. These concerns included flooding large land areas, disrupting the ecology and the habitat of fish and wildlife, changing the temperature and oxygen balance of the river water, creating a barrier to the movement of fish upstream and downstream, and modifying river flows. By 1980 concerns that the salmon runs in the Columbia River system were in jeopardy prompted congress to pass the Pacific Northwest Power Planning and Conservation Act. This Act established the Northwest Power Planning Council, which is responsible for the protection and recovery of salmon runs in the Columbia River system. The implementation of many of these laws resulted in a more complex and expensive process to obtain a license for a hydroelectric facility.

The Hydroelectric Industry Stabilizes 1986–2000

The Electric Consumers Protection Act (ECPA) of 1986, which increased the focus on non-power issues in the hydroelectric licensing process, has contributed to an increase in development costs to the point where new hydroelectric facilities are often only marginally competitive with other conventional electric generating technologies. Since 1986, the time required to obtain a hydroelectric license has grown from two years to four years and the licensing cost has doubled for projects of all sizes. Even with more efficient technology, hydroelectric generation increased only slightly between 1986 and 2000. By 1986, the average size of all hydroelectric projects in the United States was about 35,500 kilowatts. After 1986, new projects completing the licensing and construction process average less than 5,000 kilowatts in size.

The recent availability of cheap natural gas and the minimal permitting requirements for gas-fired electricity generating plants has resulted in a dramatic increase in the construction of these plants. These gas-fired plants are meeting the increasing electricity demand more economically than other generating resources.

In today's climate of increased environmental awareness, the construction of new dams is often viewed more negatively than in the past. Therefore, the construction of a new dam for hydroelectric generation is rare. Only six hydroelectric projects were constructed between 1991 and 2000 with new dam or diversion structures and all of these structures are less than 30 feet (10 meters) in height. Hydroelectric facilities are installed at only about 2 percent of the nation's dams.

Present Geographical Distribution of the Industry

Almost 70 percent of all U.S. hydroelectric generation is produced in the western United States during an average water year. The northwestern states of Washington, Oregon, Montana, Wyoming, and Idaho generate about 50 percent of all hydroelectric output. The mountains are high and water is plentiful in this region, yielding optimal conditions for hydroelectric generation. Another 20 percent of the nation's hydroelectric output occurs in the southwestern states of Colorado, Utah, Nevada, California, Arizona, and New Mexico. While these states have terrain similar to those in the northwest, the climate is drier. The southeastern states of Virginia, North Carolina, Tennessee, South Carolina, Georgia, Alabama, Mississippi, and Florida contribute about 10 percent of U.S. hydroelectric production. This region includes large TVA and utility dams with hydroelectric plants. The State of New York produces over 8 percent of the nation's hydroelectricity. At a capacity of 2,500,000 kilowatts, the New York Power Authority's Robert Moses Niagara hydroelectric project is the primary contributor of this electricity. The remainder of the country produces 12 percent of U.S. hydroelectric generation.

The Financial Picture of the Hydroelectric Industry

The financial status of the hydroelectric industry is generally healthy due to long equipment life and low maintenance and operating costs. Hydroelectric facilities in the United States had total capital value in 2000 of about $159 billion based on average new facility costs compiled by DOE of $1,700 to $2,300 per kilowatt of capacity. The gross revenue for the industry in 2000 was about $18 billion based on U.S. electricity production of 269 billion kilowatt hours and DOE's $0.066/kilowatt hour estimate for the national average value of electricity. Using DOE's data, net profit for the industry in 2000 was calculated to be about $11 billion after deducting licensing and regulatory costs (about $500 million), capital costs (about $4.6 billion), and operation and maintenance costs (about $1.9 billion). In the mid-1990s, the hydroelectric industry directly employed nearly 48,000 people and their earnings totaled approximately $2.7 billion according to DOE. Another 58,000 people indirectly provided services and material needed to operate and maintain hydroelectric dams and generating facilities. Few businesses that are 125 years old are as efficient and as important to the U.S. economy as the hydroelectric industry.

Future Directions for the Hydroelectric Industry

The hydroelectric industry has been termed "mature" by some who charge that the technical and operational aspects of the industry have changed little in the past 60 years. Recent research initiatives counter this label by establishing new concepts for design and operation that show promise for the industry. A multi-year research project is presently testing new turbine designs and will recommend a final turbine blade configuration that will allow safe passage of more than 98 percent of the fish that are directed through the turbine. The DOE also recently identified more than 30 million kilowatts of untapped hydroelectric capacity that could be constructed with minimal environmental effects at existing dams that presently have no hydroelectric generating facilities, at existing hydroelectric projects with unused potential, and even at a number of sites without dams. Follow-up studies will assess the economic issues associated with this untapped hydroelectric resource. In addition, studies to estimate the hydroelectric potential of undeveloped, small capacity, dispersed sites that could supply electricity to adjacent areas without connecting to a regional electric transmission distribution system are proceeding. Preliminary results from these efforts have improved the visibility of hydroelectric power and provide indications that the hydroelectric power industry will be vibrant and important to the country throughout the next century.

Bibliography

Barnes, Marla. "Tracking the Pioneers of Hydroelectricity." Hydro Review 16 (1997): 46.

Federal Energy Regulatory Commission. Hydroelectric Power Resources of the United States: Developed and Undeveloped. Washington, 1 January 1992.

———. Report on Hydroelectric Licensing Policies, Procedures, and Regulations: Comprehensive Review and Recommendations Pursuant to Section 603 of the Energy Act of 2000. Washington, May 2001.

Foundation for Water and Energy Education. Following Nature's Current: Hydroelectric Power in the Northwest. Salem, Oregon, 1999.

Idaho National Engineering Laboratory and United States Department of Energy—Idaho Operations Office. Hydroelectric Power Industry Economic Benefit Assessment. DOE/ID-10565.Idaho Falls, November 1996.

———. Hydropower Resources at Risk: The Status of Hydropower Regulation and Development 1997. DOE/ID-10603.Idaho Falls, September 1997.

United States Department of Energy, Energy Information Administration. Annual Energy Review 2000. DOE/EIA-0384 (2000).Washington, August 2001.

United States Department of Energy—Idaho Operations Office. Hydropower: Partnership with the Environment. 01-GA50627. Idaho Falls, June 2001.