HYDROELECTRIC (Also see Hydro and Pumped Storage Flash animations)

There are two kinds of hydroelectric plants (dams)

  1. "run-of-the-river": water is used continuously with limited reservoir storage (e.g., Bonneville on lower Columbia)
  2. "storage": water is released as needed and available (e.g., Glen Canyon in Arizona)

The dams may have several purposes including

Advantages of hydroelectric plants include

Disadvantages of hydroelectric plants include

The basis of hydroelectric power generation is that water at height has certain potential energy. The height is referred to as the head. The maximum power obtained from a hydro plant may be computed by multiplying the head, water density, and volumetric flow rate.

Hydroelectric Dam Diagram [Source: Tennessee Valley Authority (TVA)].

Also related to hydroelectric is the practice of using pumped storage facilities as an energy storage device. Pumped storage facilities consist of both high-elevation and low-elevation reservoirs. The pumped storage uses electricity during low demand times to pump water from the low-elevation reservoir to the high-elevation reservoir. Then during peak power demands the water is allowed to flow back down, turning a turbine like that used in a dam.


Pumped Storage Facility Diagram [Source: Tennessee Valley Authority (TVA)].

Last updated: September 19, 2002

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