Renewable Energy

What makes geothermal energy better than other clean energy sources?
Answered by Discovery Channel
  • Discovery Channel

    Discovery Channel

  1. Geothermal energy, drawing on the natural heat of the Earth to extract and produce energy, has the benefits of all clean-energy solutions, plus a few more:

    • Geothermal energy is the most reliably available. Other clean energy sources, such as solar or wind, are only available when the weather cooperates. Geothermal energy, by contrast, does not rely on uncontrollable outside forces.
    • Engineered geothermal systems are less constrained by natural topography when looking for a source, whereas, to have an effective wind or solar farm, the location selected must meet specific natural conditions.
    • Geothermal energy does not require as much land to produce its power as do other clean energies. A geothermal power plant only requires roughly 10 percent of the amount of land needed by a solar farm to produce the same amount of energy.

    Thus far, the U.S. is the world's leader in the use of geothermal energy. There are geothermal power plants in seven states (California, Nevada, Utah, Montana, Idaho and Hawaii). California is, by far, making the most use of the plants, with 34 online, while Nevada gets power from 16 geothermal facilities. (The remaining states have one plant apiece.) Still, though, while that sounds like a lot of plants, geothermal energy accounts for just 0.4 percent of all U.S. electricity output [source: EIA].

    There are three basic types of geothermal power plant: flash steam, dry steam and binary cycle. Flash steam is the most common type of geothermal plant. It takes hot water from deep in the Earth, converts it to steam for use in power generation and the lets the steam condense back into water, which is recycled back into the ground [source: EIA].

    Interestingly, deep underground it turns out that some rocks are better than others at providing the materials needed to create energy. Basement, sedimentary and volcanic rocks -- far enough under the surface to be hot -- are particularly well suited. In addition to being naturally hot, they are also highly stressed. This means they have developed cracks over time. These cracks are valuable because they provide a place to force water into the rock. Doing this puts pressure on the rock, creating new cracks and pushing out the heated water and steam that is used to create geothermal energy.

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