The term Geothermal Energy has been derived from Greek origins, “”Geo”” which means earth, and “therme” means heat, combined to mean: earth-heat. This form of energy has existed for as long as the Earth has existed.
Geothermal energy is a resultant of heat within the earth’s core. It falls under the category of renewable energy because of the limitless ability of the earth to produce magma and the constant transfer of heat between subsurface rock and water. This form of energy uses the steam and hot water generated inside the earth to heat buildings or produce electricity.
The question is sure to arise as to what makes the water so hot? Below the earth’s crust, the top layer of the mantle is a hot liquid rock called magma on which the earth floats. For every 328 feet below ground, the temperature increases 5.4 degrees Fahrenheit. If we progress about 10,000 feet below ground the temperature of the rock would be hot enough to boil water. The hot water reaches temperatures of 300 degrees Fahrenheit or more. This is way hotter than boiling water which id 212 degrees Fahrenheit or 100 degrees Celsius. Here the boiling water does not turn into steam because it is not in contact with the air.
Geothermal energy has been already accessed by drilling water or steam wells. This is a process similar to drilling for oil. A lot of exploring and testing is conducted to locate underground areas that contain geothermal water and then drilled to explore geothermal production wells. Once the hot water, steam travels up the wells to the surface, they are used to generate electricity in geothermal power plants or for energy saving non-electrical purposes.
People use the geo-thermally heated hot water in swimming pools and in health spas or can warm buildings during the winter, for growing plants, like in the green house. The hot water runs through insulated pipes to reach public locations.
Hot water or steam from earth’s molten core can also be converted into electricity in a geothermal power plant. Geothermal electricity generation uses either flash technology or binary technology. Using flash technology, water between 300 to 700 degrees Fahrenheit, but still in liquid form, is piped from its underground reservoir, which is highly pressurized, into a geothermal facility. Once this super-heated water is released, it flashes into steam which then operates a conventional turbine generator. Using binary technology, underground waters of lower temperatures are used for flashing. Heat from geothermal water is then transferred to a second binary liquid, which flashes into vapor upon heating and this vapor is used to drive turbines.
Geothermal heat pumps
An alternate way to tap geothermal energy is by using geothermal heat pumps to provide heat and cooling to buildings. They are also called ground-source heat pumps as they take advantage of the fact that temperatures above the ground vary a lot, but temperatures in the upper 10 feet of the Earth’s surface hold nearly constant between 50 and 60 degrees Fahrenheit. Geothermal heat pumps use this constant temperature of the earth to heat and cool buildings. They transfer heat from the ground to buildings in winter and reverse the practice in the summer.
Geothermal heat pumps are the most efficient, clean, and cost-effective systems for temperature control. Most homes still use traditional furnaces and air conditioners but geothermal heat pumps are becoming more popular with time.
Geothermal energy is an enormous but underused. Capital investment for the construction of geothermal power plants is much higher than for large coal-fired plants or new natural gas turbine technologies. But geothermal plants have reasonable operation and moderate maintenance costs and no fuel costs. Despite the fact that it is more expensive than wind power in most cases, new geothermal electricity generation facilities are increasingly competitive with fossil options.
Geothermal power is highly lucrative. A large geothermal plant can power cities completely and smaller power plants can supply energy to rural areas.
The Future of Geothermal Energy
Geothermal energy has the potential to play a major role in moving towards a cleaner, more sustainable energy system. It is one of the few renewable energy technologies that can supply continuous power. The costs for electricity from geothermal facilities are also falling down with improved technologies being implemented.
It is a heat and power resource that is clean since it hardly emits any greenhouse gases, reliable and homegrown thus making us less dependent on oil imports.