Thursday, July 19, 2007
Geothermal Energy Explained
I'm working on a LEED certified Science Center at a community college, and one of this buildings' features is geothermal energy to supply the huge amount of energy required to power the laboratory ventilation systems. I didn't know much about geothermal when I started the project, and today I found an article that may help to explain some of the mysteries of this renewable energy source.
There are two main types of systems for geothermal energy.
The first is geothermal exchange, a low cost solution that can reduce the heating and cooling costs of a building by 70%. This is basically a large coil that winds its way below the surface of the soil and then makes its way into the foundation of a house, and uses the constant thermal mass of the earth to either heat a home in winter or cool it in the summer.
The second is enhanced geothermal systems (EGS), and involves drilling to utilize the heat of the earth's core, several kilometers down with temperatures of over 465 degrees fahrenheit. This extreme temperature drives steam to turbines to produce energy.
According to the article, "In 2003, this type of geothermal power supplied just 0.416 percent of the world's energy, reports the International Energy Agency (IEA), indicating tremendous potential for expansion... Last year, an MIT study evaluated the potential for EGS in the United States, concluding it could supply a substantial portion of the country's future electricity, probably at competitive prices and with minimal environmental impact. With an investment of $1 billion over the next fifteen years, geothermal could provide at least 10 percent of U.S. electricity by 2050, says the expert panel behind the report."
The initial costs of geothermal systems can be expensive, but these systems are not subject to fluctuating fuel costs. The potential for geothermal to replace many of our current power supply systems is huge.
For years a friend of mine has been telling me about the little town of Klamath Falls and its use of geothermal to heat city buildings and even keep the streets and sidewalks free of snow in the winter. I finally googled the place, and found a cool site with schematics on the systems.
Check out Klamath Falls, yo.
For the original geothermal article at ENN