It is also a thermal power plant, but the
steam required for power generation is available naturally in some part of the
earth below the earth surface. According to various theories earth has a molten
core. The fact that volcanic action takes place in many places on the surface
of earth supports these theories.
Steam well:
Pipes are embedded at places of fresh
volcanic action called steam wells, where the molten internal mass of earth
vents to the atmosphere with very high temperatures. By sending water through
embedded pipes, steam is raised from the underground steam storage wells to the
ground level.
Separator:
The steam is then passed through the
separator where most of the dirt and sand carried by steam are removed.
Turbine:
The steam from the separator is passed
through steam drug and is used to run the turbine which in turn drives the
generator. The exhaust steam from the turbine is condensed. The condensate is
pumped into the earth to absorb the ground heat again and to get converted into
steam.
Location of plant, installation of
equipment like control unit etc., within the source of heat and the cost of
drilling deep wells as deep as 15,000 meters are some of the difficulties
commonly encountered.