What Powers Idaho?

Idaho among the nation’s leaders at generating electricity from this natural resource


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Sunset warm colors light the canyon walls over hydroelectric Dam

Josiah Wood, Features Reporter

It is easy to take for granted that we can turn on a light switch, charge a phone, or turn on the TV. We use electricity every day and depend on it to do just about everything. But have you ever wondered where your electricity comes from or how electricity is made?

Idaho Power was founded in 1916 and supplies our homes with electricity through several different methods. But one of the primary ways Idaho generates electricity—and what makes the state somewhat unique—is water power plants, or hydroelectric plants.

Idaho Power, which gets more than 57 percent of its power through hydroelectricity, owns and operates 17 hydroelectric plants along the Snake River and its tributaries. These make up Idaho’s largest source of electrical generation as the state is the third highest producer of hydroelectricity. But the largest of all these are the Hells Canyon, Oxbow and Brownlee plants.

In a year with normal precipitation, these three plants produce around 70 percent of Idaho Power’s yearly hydroelectric generation and around 30 percent of total energy in Idaho. 

So how do these hydroelectric power plants turn water into electricity?

Hydroelectric and coal-fired power plants work in in a similar way. In both, a power source is used to turn a turbine, which then turns a metal shaft in an electric generator, which is the motor that creates electricity. A coal-fired power plant uses steam to turn the turbine. A hydroelectric plant uses falling water to turn the turbine.

For hydroelectric plants, dams built on large rivers keep a significant amount of water behind it in the reservoir. Near the bottom of the dam, an intake uses gravity to draw water through a hole known as the penstock. At the end of the penstock, the turbine, which looks like a large ship propeller, is turned by the moving water. 

How much hydroelectric power is generated all depends on a few things, like reservoir storage, weather and snowpack levels on the mountain.

Something to think about the next time you turn on the lights in a room or flip on the TV.