Hoover Dam

The Hoover Dam generates a lot of power, but it also takes up a lot of space. See more renewing the grid pictures.

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­Hydroelectric power has never been a small opera­tion. Dams constructed to capture energy from massive amounts of moving water supply about 25 percent of the world's electricity [source: Bonsor]. The concept is fairly simple: Moving fluid has energy. In this case, the fluid is water, but wind turbines work on the same principle using air as the fluid. So, place a series of turbine blades in the path of rushing water, and the water is going to spin them. In spinning the blades, the water is transferring its energy to the turbine.

The turbine then transforms this energy of movement into electrical energy. In its simplest form, the rotation of the blades spins a shaft, and the shaft spins an electrical generator. The generator produces electricity, which travels to a central power grid and gets added to the overall pot of power we use to run our lives.


Hydroelectric power is the most popular form of "alternative" energy generation in the United States today -- but it doesn't com­e cheap, a­nd it's not a compact system [source: Bonsor]. These traits limit hydroelectric turbines to a small niche. There are a lot of smaller sources of water in the world that remain untapped because of the size and cost of traditional water-turbine systems. The flow has to be pretty powerful to justify spending millions of dollars to harness it.

So where are we losing potential water power?

A lot of areas, it turns out. A company has developed a new turbine system that could open up the possibilities in terms of harnessing the energy in flowing water. In this article, we'll take a look at this invention and find out what it could mean for the future of water power. Perhaps most intriguing in all of this -- can we start harnessing the energy in a toilet flush?