Like any energy source there are a wide variety of applications for geothermal systems. They range anywhere from the production of electricity to the heating of a backyard pool.
Electricity Production:
There are limited number of areas in the world that are capable of full scale energy production economically with the technology we have today. These areas include but are not limited to Iceland, New Zealand, some parts of Italy and France, China, and Geysers in California. There are three main methods that the plants use to generate power.
Dry Steam:
One is called the dry steam method were steam from geothermal reservoirs with temperatures greater than 220ºC is piped directly to a turbine from which electricity is produced.
[9]Flash Steam:
The second method is called the flash steam method in which water whose temperature is greater than 180ºC flows up through wells due to pressure. As the water rises the pressure decreases and flashes to steam that is then fed to a turbine from which electricity is generated.
[10]Organic Rankine Cycle:
The last method is know as an Organic Rankine Cycle (ORC). These types of plants can produce electricity over a wide range of temperatures generally from about 110-180ºC. This method sometimes incorporates flash steaming to rotate a turbine in order to initiate power generation. This steam is then used to vaporize a secondary fluid which is usually some kind of hydrocarbon fluid like tetrafluoroethane (r-134a refrigerant) which has a lower boiling point than water. The secondary fluid get vaporized in a heat exchanger by which the vapor is then used to spin a secondary turbine which then produces electricity.
[11]Residential Uses:
The most common use of geothermal systems in a residential environment is for the heating and cooling of homes and office buildings. By using geothermal heating and cooling home owners are capable of saving anywhere from 20-60% on utility costs per year. Geothermal energy can also be used for in-floor heating, heated sidewalks and driveways as well as pools and saunas.
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