Geysers Kids

Have you ever seen pictures of a volcano or a geyser? If so, then you've seen geothermal energy in action!

The word geothermal comes from the Greek word geo - meaning earth, and therme - meaning heat. Ancient people first used geothermal energy to heat water for bathing. Calpine uses geothermal energy to generate energy for 725,000 homes, or a city the size of San Francisco. In fact, The Geysers provides electricity for homes and businesses from the Golden Gate Bridge to the Oregon border.

Geothermal activity occurs in places where magma is very close to the earth's crust. Sometimes this can be seen as a volcano. Sometimes it can be seen as geysers or hot springs. At The Geysers, this is seen as a geothermal resource.

Magma in the earth heats water in the earth's crust, making geothermal water. When the water boils and pressure builds, the water and steam can shoot up into the air in the form of a geyser.

Even though Calpine's energy facility is called The Geysers, it was not named correctly because there are no true geysers in the area, only fumaroles and hot springs. At The Geysers, water is trapped below the earth's crust by a layer of hard rock much like a lid on a pot. This "lid" caps the geothermal reservoir.

Calpine drills wells approximately two miles deep and inserts a pipe into the geothermal reservoir like a drinking straw into a soda.

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The steam is piped out of the earth and cleaned of bits of dirt and rocks so as not to damage the blades of the turbines in the geothermal power plant. The cleaned steam is used to spin the turbine, which is attached by a shaft to the generator. It is the generator turning at 3600 revolutions per minute that generates the electricity. That would be like you being able to spin 3600 times in one minute!

After the steam goes through the turbine, it is cooled in the condenser and turned back into water. This water is recycled back into the earth through an injection well so that it can be re-heated and used as steam to produce electricity again.

A geothermal power plant is like a regular power plant except that no fuel is burned to heat water into steam, because the steam comes directly from the earth. This is what makes geothermal energy a naturally occurring process, or a renewable resource.