On average, 7 percent of the electricity in the United States is produced by hydroelectric systems. (See Reference 1) Although water rushing across turbines to produce energy is renewable and reduces greenhouse gas emissions, hydroelectric power carries some controversy because it changes the landscape and affects fish migration. (See Reference 1) Finding ways to harness the power of water goes back several centuries and continues through today.
Humans have been using water to power our heavy work for more than two thousand years. Ancient civilizations, including the Greeks and Romans, diverted water to push wheels that would then turn mills to grind grain for bread. Before the Industrial Revolution, water was the main power source for milling lumber and grain, and powering small machinery. (See References 2 and 4)
Dams using hydraulic reaction turbines were first used to generate electricity in the U.S. in the 1880s (See Reference 4) Within 20 years of the first few hydroelectric dams, nearly 40 percent of the electricity in the U.S. was being produced hydroelectrically. (See Reference 3) From 1905 through the 1930s, several large dams, including the Hoover and Roosevelt dams, were added to meet the public demand for electricity in their homes. (See Reference 4) By 1940, three-quarters of the electricity for the western states came from hydroelectric power. (See Reference 3)
To the Present
In the mid-20th century, hydroelectric power through dams could not meet the demands of the growing U.S. population and the increase in homes that used electric lighting and appliances. New forms of power generation were developed such as nuclear power, coal, and natural gas. (See Reference 3) Currently, hydroelectric dams running at their maximum produce only enough electricity to power 10 percent of the homes in the U.S. Controversies such as the impediment of fish migration and the impact of changing a river's natural course have lead to dams having a poor image in the public eye, despite the power source being renewable and relatively nonpolluting.
In the 1960s and '70s, operators of hydroelectric dams recognized the problem of blocking fish migration. Many dams now implement fish ladders and spillways to allow fish such as salmon to pass through. (See Reference 2) Some dams that have drastically altered river ways and landscapes may be removed to restore the land. However, dams aren't the only way to make electricity from water. Projects are already underway to derive energy from ocean waves, capture the energy from marine currents, and build less-intrusive turbines in rivers to allow us to continue using this renewable resource to generate electricity.
After working in scientific research for more than 10 years, Tammie Painter began her writing career in 2008. Her articles have appeared in "Northwest Travel," "Herb Companion" and "American Gardener." She has published four books, including "Simply Soft Cheese" and "Easy Preserving." Painter has a Bachelor of Science in biology from Portland State University.
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