The steam goes directly to a turbine, which drives a generator that produces electricity.The Geysers is a complex of 22 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains 116 km north of San Francisco, California.
This type of Geothermal power plants are very rare. They involve dry steam which has a temperature greater than 455°F. This steam is directly pumped from the geothermal reservoir to run the turbines that generate power. These power plants need steam in huge amounts and the emission of gases is minimal. The block diagram of a dry steam power plant is shown in the figure at the top.
This is the oldest type of geothermal power plant. It was first used at Lardarello in Italy in 1904. Steam technology is used today at ‘The Geysers’ in northern California, the world's largest single source of geothermal electricity. These plants emit only excess steam and very minor amounts of gases. Refer to the image at the bottom.
Geothermal Energy is utilized in many parts of the world. Most of the Geothermal power comes from the United States. There are some other places like Atlantic coast, Texas, etc, which do produce considerable amount of Geothermal power.
The initial construction costs for geothermal power plants are high because geothermal wells and power plants must be constructed at the same time. Over the time the cost of production of electricity becomes less, as the availability of the fuel becomes predictable. The power plant literally sits on top of its fuel source. So there would be no transmission of fuel from one place to other.