Hydropower is one of the oldest power sources, and it is a renewable source. Hydropower is less costly than most energy sources, and states in the United States that get the majority of their power from water have lower energy bills than the rest of the nation.
Hydropower is clean and does not produce any pollution or poisonous byproducts, such as greenhouse gases. Also hydropower is the leading source of renewable energy, producing more than 97 percent of all electricity coming from renewable sources. Hydroelectric dams form reservoirs that provide water-based recreational opportunities, such as fishing and water sports.
The major advantage of hydropower energy over other renewable energy sources is that average rainfall is highly predictable, meaning output is reliable. Further, river flow does not fluctuate easily, as is the case with wind energy.
Some hydropower facilities quickly rise from zero power to maximum output. They are ideal in meeting abrupt changes in electricity demand and provide essential back-up power during major electricity disruptions.
About 20 percent of the world’s electricity comes from hydropower, with about 10 percent of electricity in the United States coming from water. Hydropower is the most efficient way of producing electricity, with modern hydro turbines able to convert as much as 90 percent of the available energy into electricity. Fossil fuel plants are about 50 percent efficient.