Going underground
Going underground! I’m going underground! I’m going underground! — The Jam, 1979 Geothermal is smart, easy to use and in most cases relies on a few simple components. It has been around for milleniums, but what is it exactly? Well, it has two fronts. One is for heating and the other for electricity. The means of heating vary depending on the type of heat trying to be obtained. If you live near a hot spring, the choice is easy. Depending on zoning requirements, you could tap into the spring and heat your home or business directly. Just some line and a pump. In most cases, however, you are using a more available but lower medium of heat transfer. To do this a set of underground pipes with a fluid medium — usually water with antifreeze protection that takes advantage of the heat difference of the outside temperature and the underground temperature vis-a-vis a heat pump. The heat pump then transfers its energy to heating and cooling your home. The heat pump, which embraces some complicated physics, is a study in itself. Here’s a little mind twister: evaporation is a cooling process. On the practical side, you need to run pipe far enough underground that will ensure a temperature differential useful for the volume of the house and its location on the map. Some pipelines go vertical some 300 feet and others go horizontal, as shallow as four feet, with about 400 to 600 feet of pipe. The other energy produced by geothermal is electricity. Trivia answer-question for you game players: Answer: The first geothermally powered electricity produced was produced in this country and in this year — cue the theme music — Question: What was 1904 in Italy? A power station was built there in 1911. Geothermally produced electricity has a much different approach than the geothermal discussed above. Power production requires access to steam. The stronger the better. I don’t want to bore my readers with the physics of steam, but picture if you will that one form of steam is not the same as another. You can observe this when you are heating your coffee water the old-fashioned way on an open stove. When the whistle on the kettle initially engages, you can sense the intensity of the steam by the volume and frequency of the whistle. It begins as a lower frequency and lower volume of sound. As you let the kettle sit, the frequency increases and the volume goes up. This gives a sense of what I am trying to convey. To turn an efficient power generating turbine you need a powerful jet of steam. To create steam this powerful you need to drill deep into the ground to reach those higher temperatures. Way down, like up to five miles. However, this is where the downside exists, earthquakes. Earthquakes have been blamed on several geothermal projects in California, Switzerland and Italy. Drilling for effective geothermal steam generation has the equivalent impact that hydrofracking has. Sites must be carefully selected. The study of what causes earthquakes is for another time. There are different mediums used to produce geothermal electricity by choosing a medium with a lower boiling point. These however tend not to be cost effective. And now a word about Iceland and Olafur Grimsson: Iceland produces nearly all its own energy, most notably by geothermal. Iceland like most islands, sits with a volcano. It utilizes this abundant resource to heat its homes and commercial buildings. Even the road to the Reykjavik airport is heated. Most of Iceland’s vehicles run on hydrogen therefore the country imports very little oil. Iceland is, in my humble opinion, the most technologically advanced energy infrastructure. It is a role model for other countries. On Sept. 26, 2007 Olafur Grimsson visited the Energy and Natural Resource Committee of the USA to give a speech on alternative energy. He provided the committee with a 31-page document called “A Clean Energy Future For the United States: The case for Geothermal Power.” In gratitude for his service and genuine altruism, only two of 43 committee members attended. Oh, by the way Olafur, as he known by his countrymen, was “just” the president of Iceland. So where is geothermal today? Geothermal heating is expanding in the home use field, especially for new homes with heat pumps as part of their heating. It has proven to be a very cost-effective move for the new home owner. The only extra costs to the new home are the excavation, for a horizontal system, and the drilling for a vertical one, along with the piping. By the way, vertical wells for this system do not cause any seismic activity whatsoever. Geothermal heating is safe all the way around. However, many projects are on hold for producing geothermal electricity. Turbines must be improved to run effectively at lower pressures. Lower boiling point mediums, such as some alcohol-based fluids, have been considered. Thereby reducing the need for drilling deeper and reducing the risk of earthquakes. Many of these projects are simply not cost-effective. Wouldn’t it be great if the ever increasing number of hydrofracking sites would take the same cue? I ask the reader to review the aforementioned document by former Iceland President Grimsson. It says it’s available at the above Senate Committee’s website — www.energy.senate.gov — however, I have tried and was unable to retrieve it from the website just as I was unable to contact this committee by phone. For a reprint please feel free to contact me at jimbobreski@yahoo.com.
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AuthorJames Bobreski is a process control engineer who has been in the field of electric power production for 43 years. His “Alternate Energy” column runs monthly. Archives
June 2020
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