The construction of the O’Shaughnessy Dam and Hetch Hetchy reservoir in Yosemite National Park (1923) was seen as a major loss for conservationists. Siting: Some proposed sites for hydroelectric power plants in the U.S. Large dams have greatly reduced Salmon populations of the Pacific Northwest.ģ. Effect on fish populations: The negative environmental impacts of dams adversely affect fish populations by reducing thousands of miles of fish habitat by limiting access to spawning grounds. International Rivers – an environmental NGO – reports that large dams have led to the extinction of fish species, disappearance of birds in floodplains, losses of forest, wetland, and farmland, erosion of coastal deltas, and other destructive impacts.Ģ. Hydroelectric dams impact a river’s flow, temperature, chemistry, and silt load. Large dams have large environmental footprints. were built without considering their impact on ecosystems. High environmental impact: Most of the hydroelectric dams constructed in the U.S. Remember, levelized costs of energy are calculated by taking the total cost to build and operate a new power plant over its lifetime divided by its expected energy output – measured in dollars per kilowatt hour ($/kW-hr). The LCOE for hydropower is $0.08/kW-hr, making it a competitive with coal and natural ($.07-$0.14/kW-hr). Cost-effective: Hydroelectric energy has a low levelized cost of energy (LCOE) compared to conventional sources (coal and natural gas). Reliable: Large reservoirs behind dams mean that power plant operators are able to control the flow and output of electricity to match energy demand.Ĥ. The energy conversion efficiencies for solar and wind are much lower, averaging 15% for solar and 60% (theoretical limit) for wind respectively.ģ. Approximately 90% of the energy captured is able to be converted into electrical energy. Energy conversion efficiency is the ratio between the output of an energy conversion machine and its energy input – the higher the ratio, the more efficient the power plant. Efficient: Hydropower has a very high energy conversion efficiency. Clean: Generating electricity from hydro-energy does not produce harmful greenhouse gases.Ģ. The decline in electrical generation from hydropower was a result of increased investment in other sources of energy, siting limitations for large-scale hydroelectric plants, and rising environmental concerns about impact of dams on aquatic ecosystems. Today, hydroelectric generation provides roughly 6% of the United States’ electricity. Dam construction peaked in the 1960’s and has since gradually declined. Hydropower was the first large-scale renewable energy source used in the U.S., accounting for one third of the nation’s total electrical needs in the 1940’s. Hydropower is energy produced by moving water through a turbine. Continue reading to learn more! What is Hydropower? Today we discuss two new forms of renewable energy, hydro and tidal power. Our first post introduced the idea of using renewable energy as a way to keep up with economic demand while reducing our impact on the environment and our second post explored the benefits and limitations to solar and wind energy. Welcome back! This is post three of our four-part series on renewable energy. What are the Pros and Cons of Hydropower and Tidal Energy
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