For over 2,000 years water has been used as an energy source and continues to power through the centuries, leading the way in renewable power.
Hydropower is the largest source of renewable power in the United States, accounting for about 7% of all electricity generated and 56% of the nation’s renewable generation (more information at hydro.org). It is used in every state and avoids as much carbon pollution as removing 38 million passenger cars each year. Not only is it an available source of clean energy, but hydropower facilities are also reliable sources of energy that can meet rapidly changing demands for electricity.
Hydropower refers to electricity generated using the energy of moving water (hydroelectricity) and is most commonly associated with the use of dams to generate electricity. Ocean Energy is the term used to describe different forms of renewable energy that is harnessed from the ocean. Ocean Energy and Hydropower have been separated into two different renewable energy sections to organize the renewable energy sources available through the ocean, from renewable energy sources available through other water sources.
There are three types of hydropower facilities that range in sizes from micro to large. The three types include impoundment, diversion, and pumped storage.
History of Hydro
Just like many of the different types of renewable energy sources, water has been used as an energy source for over 2,000 years, dating back to the Ancient Greeks. Through the use of water wheels, the Greeks were able to grind their wheat into flour. Over the years, water wheels built up their resumes to include producing power to saw through wood and power textile mills and manufacturing plants. Breakthroughs in hydroelectricity started to appear around the mid-1700s, and by the late 1800s, plants began to operate in the United States.
For a more detailed history of hydropower, please visit History of Hydropower.
For more information on any of the hydropower technologies or hydropower in general, please visit the U.S. Department of Energy’s page on Types of Hydropower Plants.
For more information on how impoundment works, please visit EDF Energy - How electricity is generated through hydropower.
A diversion, often called run-of-river, is very similar to an impoundment facility, except there is no dam or reservoir and tends to be on a smaller scale. Run-of-river systems cannot exceed storage of 48 hours of water supply by definition. The systems rely on naturally flowing rivers that have a steady and consistent flow. The pitch of the river is also an important factor as the greater the distance that the water falls, then the greater the amount of energy.
Run-of-river facilities divert a portion of a river through a canal or penstock and lead it to a generating house. The generating house, or powerhouse, is home to turbines and the power generation unit. The river water flows through the penstock and forcefully passes through the blades of one or more turbines causing them to turn. Just like impoundment, the spinning turbines essentially run the generator which generates electricity. The water is then fed back into the river further downstream.
Want to learn more? Check out National Hydropower Association’s pages on Conduit Hydropower and Converting Non-Powered Dams.
Hydropower does exist in Connecticut, one example being the Kirby Mill in Mansfield. It is a run-of-river system with a highly efficient turbine and a “fish friendly” propeller.
If you are interested in learning more about hydropower technology or would like to look into installing a hydropower system, please visit the Clean Energy Finance and Investment Authority.
Hydropower is listed as a Class I renewable energy source as defined in the Connecticut General Statutes (CGS) Section 16-1(a)(26)(x).