Hydropower Facts

Hydropower is the most common renewable energy technology. Humans have been harnessing water to perform work for thousands of years. Before electricity became widely used in industry, flowing water was harnessed to power saw mills, flour mills, textile machines, and for irrigation. Hydroelectric energy is truly a versatile renewable energy source that still offers great potential.

Important Facts About Hydropower:

  1. Hydropower is currently the largest source of renewable power, generating nearly 10% of the electricity used in the United States.
  2. Today, hydropower, including pumped storage, supplies over 13 percent of the electrical generating capacity of the United States. Coal-fired steam generation is still the number one source of electricity in the United States. Hydroelectric pumped storage shows up as a negative factor in electricity production.
  3. More electricity is used to pump the water to the upper reservoirs than is produced when the pumped-storage units are used to generate electricity. The benefit of pumped-storage is the ability to effectively shift capacity from periods of low energy use to periods of high energy use.
  4. Hydropower is the primary contributor of renewable energy in the United States.
  5. The costs of generating hydropower are the lowest of all sources of electricity.
  6. The hydroelectricity currently produced each year in the United States is equivalent to nearly 500 million barrels of oil. This presently represents a value for existing hydrogeneration of about $9 billion annually.
  7. Hydropower generation is not a contributor to atmospheric emissions, which are a growing problem on both national and global levels.
  8. Hydropower is presently the most efficient way to produce energy with each kilowatt-hour of hydroelectricity being produced at an efficiency more than twice that of any competing energy resource.
  9. Only 3 percent of some 80,000 existing dams in the United States have hydropower facilities.

Additional Resources
  • FERC issues licenses for the construction of a new project, or the continuance of an existing project (relicensing); and provides oversight of all ongoing project operations, including dam safety inspections and environmental monitoring.
  • National Inventory of Dams is a collection of information about dams in the United States and its territories, produced by the U.S. Army Corps of Engineers.
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