Alternative Power Systems 123
left in the loop. This system of loops avoids damage to the steam turbine
blades. After the steam goes through the turbine, it goes to a condenser,
where it is combined with cooler water. This water is pumped to cooling
towers, where the water temperature is reduced. This part of the geother-
mal system is similar to conventional steam systems.
The geothermal power production method offers another alternative
method of producing electrical power. This method makes it possible to
control energy, in the form of steam or heated water, that is produced by
natural geysers or underground channels. The high-pressure steam for
power production is made without burning any of our fossil fuels. Thus,
this method can be used to drive turbine-generator systems, such as the
one at the Geysers system in California.
The setting up of a geothermal power plant requires the drilling of holes
deep into the surface of the earth. One hole may be used to send cold wa-
ter down into the tremendously hot material located under the surface of
the earth. An adjacently drilled hole could be used to bring steam back to
the surface. This method is capable of being used in any area of the world,
but it requires drilling holes up to 10 miles deep. On the other hand, natu-Figure 5-3. Drawing of a basic geothermal power system that illustrates the un-
derground structure (Courtesy Pacific Gas and Electric Co.)