One of the greatest wonders of this planet is its capacity to generate heat. The center of the earth contains a massive amount of heat, which is a form of energy. Even though humans have benefited form geothermal heat in one form or another for millennia, the Italians get most of the credit for its discovery and utilization. Whichever way you look at it, geothermal is a viable option with an established track record.
Geothermal Sources
Geothermal power comes from the heat of the soil. It also comes from hot water, as well as from rocks having high temperatures buried miles beneath the earth’s surface. The heat coming from the earth, which can be accessed by drilling steam wells deep into the earth’s surface in a similar fashion as drilling for oil, is then used to move the turbines connected to a generator, which then produces electricity.
Geothermal Plants
A large site that utilizes geothermal energy to provide electricity for consumers is known as a geothermal power plant. Underground wells a mile or more in depth are drilled to tap into the geothermal reservoirs of extremely hot water and steam. The steam then drives turbines which in turn drive generators that produce electricity. If you picture a forceful eruption from Mount St. Helen, we have an idea of the power that can be generated from geothermal energy.
Today there are three types of geothermal power plants. One is dry steam plants, which use geothermal steam to drive turbines. The second is flash steam plants, which use the flashed steam produced from pulling high-pressure hot water from the depths of the earth into low-pressure tanks to drive turbines. The third is binary-cycle plants, which use the technique of passing hot geothermal water by another fluid with a lower boiling point. This process creates strong vapors that drive the turbines.
DOE and Geothermal Energy
The Department of Energy (DOE) recognizes the huge amounts of power that geothermal power plants can produce, in addition to its minimal environmental impact. Their Geothermal Technology Development Program supports the progress of geothermal plants in the country. Working with Congress, the program sponsors research and development on geothermal technology.
Cost of Geothermal Energy
The Geysers, California is host for the world’s largest single geothermal source. The cost of electricity coming from this geothermal power plant costs between $0.03 and $0.035 per kWh. This plant has been in existence since 1960. A power plant today would likely charge $0.05 per kWh for geothermal energy use.
Your Own Geothermal Source at Home
You can actually make use of a geothermal heat pump (GHPs) to decrease electrical consumption. Usually, these pumps, also called GeoExchange pumps, use 25-50% less electricity. Geothermal systems, consisting of pipes, a heat exchanger, and ductwork, utilize the relatively constant temperature of the earth to cool the house in the summer and warm the house in the winter. Instead of using fluctuating outside air temperature as an exchange medium like traditional heat pumps, GHPs exchange heat with the earth through a ground heat exchanger. In the US, about 50,000 geothermal heat pumps are installed every year. The initial cost of installation may be a bit expensive, but since the system lasts for approximately 25 years, you will be able to appreciate the long-term savings of a geothermal system.
