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Understanding Geothermal Energy April 14, 2008

Posted by OldGuy in Alternatives.

The term geothermal is from the Greek “geo” meaning earth and “therine” meaning heat.  That means that geothermal energy is harvested from the natural heat of the earth.  That means it’s only suitable for use in areas of the globe where the heat of the earth’s mantle is close enough to the surface to be reached easily.  This includes areas with volcanic action and geyser regions, such as in the Yellowstone region. 


Prince Piero Ginori Conti of Italy tested the first geothermal generator on 4 July 1904, at the Larderello dry steam field in Italy.  The first geothermal power plant in the United States was made in 1922 by John D. Grant at The Geysers Resort Hotel, but it fell into disuse, because other methods of generation cost less at the time.  The process was reproduced in Iceland in 1910, where plants have been generating electricity since.  

Geothermal energy is generally created when water is injected into a geothermal hot zone, and then harvested as steam from a production well.  

In a dry steam process, steam flows directly through a turbine (creating energy).  The cooling steam is collected in a condensor and then to a cooling tower (the cooling tower also provides the water used in the condensor, and the water injected into the heat layer to begin the process again.

In the Flash Steam process  -the most common – water is pumped under pressure to the geothermal zone.  The production well extracts the hot water into a “brine” tank, and then heated (flashed) to 360 degrees, producing steam for the turbine.  The steam is condensed and then cooled for re-use in the injection well.  The excess water brine is then pumped off to be used in industrial or residential home heating.

Geothermal power is currently generated in over 20 countries around the world including Iceland, the United States, Italy, France, Samogitia (Lithuania), New Zealand, Mexico, Nicaragua, Costa Rica, Russia, the Philippines, Indonesia, the People’s Republic of China, Japan and Saint Kitts and Nevis.  


Less than 1% of the world’s energy supply is created by geothermal, although it dominates total energy production in some countries .  It accounts for 3.24% of the power in Mexico and 27% of the electricity generation in the Phillipines.  Over 26% of Iceland’s electrical energy is generated from geothermal sources. In addition, geothermal heating is used to heat 87% of homes in Iceland. Icelanders plan to be 100% non-fossil fuel in the near future.  Chevron Corporation is the world’s largest producer of geothermal energy.


Sources:  the The Idaho National Laboratory,  Geysir Green Energy Company, and Wikipedia




1. where geothermal energy is created - May 15, 2008

[…] natural heat of the earth.? That means it??s only suitable for use in areas of the globe where thehttps://energytech.wordpress.com/2008/04/14/understanding-geothermal-energy/Cosmic Log: The far-off fusion race MSNBC Science editor Alan Boyle’s Weblog: One of the nation’s […]

2. Joe Duncan - September 23, 2008

I am studying Fluid Power here in Washington state. When I think about my future career in Hydraulics, Pneumatics, Machine Controls and the possibilities of Geothermal Energy here in the United States, I would like to share my thoughts about harvesting Geotherma Energy in Alaska. There are 29 active Volcanoes there and an unlimited amout of natural water to fit the solution. I understand that Geothermal Energy can be harvested 365 days a year, 24 hours a day. It seems to me that this would be an ideal place to begin such a mission. It would also provide the residents of Alaska with plenty of energy and heat to keep warm. If Nuclear and Coal Energy tactics take so many years of investing and developing, it would make more sense to spread the use of geothermal energy thoughout this particular region. The energy could theoretally be ready to harvest within the first few months of installation. Arn’t the tools used for drilling the injection wells and main production wells the same used for drilling oil? I would like to know more about the subject and I am extremely interested in partaking in the project. I will be looking for a job after I graduate this next spring. My last 3 quarters I made the Presidents Honor Roll and feel commited to the obligation to helping my country achieve new and cleaner energy sources for the future of the United States people.
-Joe Duncan, Fluid Power student at Spokane Community College

3. sandrar - September 10, 2009

Hi! I was surfing and found your blog post… nice! I love your blog. 🙂 Cheers! Sandra. R.

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