HYDROELECTRIC ENERGY: By taking advantage of gravity and the water cycle, we have tapped into one of nature's engines to create a useful form of energy. In fact, humans have been capturing the energy of moving water for thousands of years. Today, harnessing the power of moving water to generate electricity, known as hydroelectric power, is the largest source of emissions-free, renewable electricity in the United States and worldwide. Although the generation of hydropower does not emit air pollution or greenhouse gas emissions, it can have negative environmental and social consequences.
Blocking rivers with dams can degrade water quality, damage aquatic and riparian habitat, block migratory fish passage, and displace local communities. The benefits and drawbacks of any proposed hydropower development must be weighed before moving forward with any project. Still, if it's done right, hydropower can be a sustainable and non-polluting source of electricity that can help decrease our dependence on fossil fuels and reduce the threat of global warming.