The biggest environmental issue of the current time period, climate change, is fueled primarily by the greenhouse effect. This occurs when gases emitted by human activity, such as carbon dioxide, methane, and nitrous oxide, trap heat within the Earth’s atmosphere and cause the planet to warm. Combustion of fuels for energy is perhaps the biggest contributor of these greenhouse gases. This has led conservationists and scientists to seek clean, renewable energy that avoids emissions which are harmful to the natural world.

The Itaipu Dam, one of the largest hydroelectric plants in the world. Image Source.

One of these options is harnessing the power of Earth’s bodies of water to create and store energy. Hydroelectric power is the most common type of renewable energy used today, with hydroelectric dams being the primary form. In the United States, hydroelectric power accounts for about 7% of total electricity generation.  Dams used for electricity generation hold water upstream in reservoirs. Water can be held until energy generation is needed. Flowing downstream through the plant, the force of the passing water rotates turbines, which in turn generate electricity. The water is released on the other side of the dam into a river. The largest hydroelectric dam in the United States is the Grand Coulee Dam (cover image) on the Columbia River in the state of Washington.  The largest dam in the world is the Three Gorges Dam (pictured below) on the Yangtze River in China, which can generate up to 22,500 megawatts of power from its 32 turbines.

Hydroelectric dams can pose challenges to conservation efforts. Image Source.

While hydroelectric power is often a great source of minimal-emission energy, its environmental impacts often come under scrutiny. The conversion of sections of rivers into dams can have a massive ecological effect. Upstream environments can be completely destroyed by the formation of a reservoir, eliminating forested buffers and destroying valuable habitat for wildlife. In the water, dams disrupt the normal functioning of the river ecosystem. Water temperature, flow patterns and underwater habitats can be significantly altered. For instance, migratory fish may be severely hamstrung in their efforts to navigate rivers and spawn. Due to these multiple effects, environmental groups typically resist the construction of new dams, instead opting to update older ones. This can be a challenge, however, as energy companies may not be willing to voluntarily spend resources to make their operations more environmentally friendly.

Ultimately, when done responsibly in a way that accounts for its variety of effects, hydropower is a crucial component to the environmental policy of the United States. Modernizing hydroelectric facilities while mitigating environmental impacts is likely one of the best ways for the United States to avoid the emissions that come with coal and gas power. In a future that must rely more heavily on conservation and sustainability, hydroelectric power will only become more important as part of the backbone of U.S. energy generation.

Cover Image Source.