Geothermal energy uses heat from the Earth. Geothermal is a renewable energy source made possible by the same tectonic activity that causes local earthquakes and the rising mountains. Geothermal is an endless supply of energy from which we can generate power. The earth's rigged outer shell, the lithosphere, consisting of the crust and upper mantle, rests upon the hotter and more plastic region of the upper mantle, below the crust, called the asthenosphere.
The thickness of the Earth's crust varies from a few miles to perhaps hundred fifty miles. Rock heated by magma deep below the surface boils water trapped in underground reservoirs – sometimes as hot as 700 degree F. Some of this hot geothermal water travels back up through faults and cracks and reaches the earth's surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock This natural collection of hot water is called a hydrothermal reservoir. We already enjoy some of this activity via natural hot springs. Much of the world is underlain (3-6 miles down), by hot dry rock – no water, but lots of heat.
Today we use only a tiny fraction of the total geothermal resource. More than 10,000 megawatts (MW) of geothermal electricity are currently produced around the world, including about 3,102 MW of capacity in the United States.
Modern wells, mostly used in oil industry and geothermal plants, drilled using rotary drills, can achieve lengths of over 38,000 feet (12 000 meters). The well is created by drilling a hole 5 to 36 inches (13–90 cm) in diameter into the Earth.
Many people ignores geothermal, because it is perceived to be too small and too localized to make difference. Their opinions are base on performance of existing geothermal plants which depend on naturally formed geothermal reservoir which are limited and sometimes located in restricted areas.
For long time in the peoples mind was and still is the intriguing question: "Will we be able in the future, somehow, to use effectively the heat of the deep, hot dry rock formations of Earth's crust, and possibly even deeper, almost unlimited energy in Earth's magma".
Accordingly, there is a need in the field of geothermal energy for an apparatus and method for efficiently using the enormous heat resources of the Earth's crust that are accessible by using even current drilling technology although we have developed new drilling methodology for drilling deeper and wider well bore.