About Geothermal Enery

Geothermal energy is heat from the earth. This heat can be utilized to meet energy needs. Heat from the Earth’s core can melt rock into magma, which in turn heats the surrounding rock and underground reservoirs of water (hydrothermal energy). Power plants can utilize this energy to generate electricity. Wells are drilled a mile or more into the reservoirs to tap steam or very hot water which is used to drive turbines that produce electricity.

Typically, geothermal energy is thought of as coming from extremely hot rocks or magma deep under ground. But heat pumps can allow heating and cooling in houses and buildings to be accomplished by taking advantage of the almost universally constant temperature in the upper 10 feet of the Earth’s surface, which ranges between 50 and 60 degrees F. We will focus instead on electricity produced from geothermal energy derived from sources deep underground.

There are currently three types of hydrothermal plants in use.

Dry-steam plants directly use geothermal steam to drive the turbines.

Flashed-steam plants pull deep, high-pressure hot water into lower-pressure tanks, where it flashes to steam and drives the turbines.

Binary-cycle plants pass moderately hot geothermal water by a secondary fluid with a lower boiling point than water. The secondary fluid flashes to steam, and drives the turbines.

Hot water is also used directly to heat homes in Iceland and other areas.

Hot rocks that are not associated with water are more plentiful than hydrothermal resources, but this energy is more difficult to tap due to the depth and lack of a steam conduit to carry the heat to the surface. Experimental operations conducted by the Department of Energy have successfully drilled down to hot dry rock reservoirs and injected water to be heated and returned to the surface as steam. This technology is only appropriate in areas with ample surface water, not arid regions.