Student Post: Hydroelectric Power – The Three Gorges Dam

Harnessing the power of falling water to create energy has been a technique used from the earliest days of energy production.  According to the U.S. Geological Survey, currently about 7 percent of our nation’s power is produced in hydroelectric plants by power generators placed inside dams. The Great Depression and the need to provide electricity to rural areas led to public programs such as the Tennessee Valley Authority, the Bonneville Power Administration Act of 1937, and construction of the Hoover Dam.  In the past few decades there have been no new large-scale dam construction projects in the United States, and hydroelectric continues to make up a relatively small share of our overall power production. Worldwide, however, hydroelectric power makes up about 19 percent of energy production, with China being the largest producer. http://ga.water.usgs.gov/edu/wuhy.html

While hydroelectric power is considered to be a renewable and clean energy source, it has definite advantages but also creates some negative impacts. Construction of a dam can provide a durable, constant source of energy and production can be stopped when energy is not needed. The electricity produced does not generate any greenhouse gases, and water is a clean source of fuel. However, building large dams requires surrounding areas to be evacuated and can cause significant damage to the ecological system. http://www.earthconservation.net/hydroelectric-power-plant-its-pros-and-cons.html

In China’s large and expanding hydroelectric industry, the Three Gorges Dam is the world’s largest dam facility.  The Three Gorges dam was built in order to increase production of electricity and reduce emissions of greenhouse gases in China, as well as to reduce flooding. The dam harnesses the Yangtze River, which is the longest river in Asia, and was completed in 2008.  The estimated output of the dam is that it will provide approximately one-tenth of China’s energy needs. Critics of the dam pointed to ecological concerns because the dam will disrupt silt flows in the river, depriving fish and agricultural land of vital nutrients downstream. The Three Gorges project also led to the dislocation of 1.27 million people. http://www.power-technology.com/projects/gorges/. In addition, there are considerable environmental impacts resulting from the Three Gorges Dam. In addition to fertile farm land, hundreds of factories and dumps were submerged as a result of the dam. This debris, along with upstream industrial centers, has resulted in an incredibly polluted reservoir. Changing water levels on the reservoir have triggered landslides, and there are concerns that earthquakes and other natural disasters could follow.

Are the ecological risks of hydroelectricity worth the benefits? As the world continues to look to renewable energy sources to decrease our dependence on fossil fuels, the Three Gorges Dam will be one to watch. Being a relatively new dam and built on such a large scale, its impacts on the environment may not be fully realized for years.