Geothermal Generated Electricity - is it a Viable Energy Option?
Author: Paul Calhoun
It is increasingly being recognized that the world has to replace fossil fuels with alternate fuels. This recognition is being driven by three premises:
First: Fossil fuels, coal, oil and natural gas, are accelerating in cost as they are consumed in ever-increasing amounts. The February 12, 2008 issue of the Wall Street Journal has two articles to re-enforce this premise. The first article, "China Spurs Coal-Price Surge," by Shai Oster and Ann Davis, informs us that the price of coal out of Newcastle, Australia has increased from $40 USD at the start of 2007to $125 USA at the 2008. The article goes on to inform us that coal will join oil and natural gas in 2015 as sources that are depleting.
The second article, "The Future of World Oil Supply - Filling the Missing Link," by Peter Jackson and Keith Eastwood ,informs us that the world's oil fields will reach peak production around 2025 and then start a rapid decline in production. Second: Oil and gas imports from foreign sources raise concerns over our long-term energy security. We all have witnessed the jump in oil prices caused by wars, strikes and disrupted supplies. Gregory Meyers' article in the same issue of the Wall Street Journal cited Venezuelan President Hugo Chavez' threat to disrupt the supply of oil to the USA because of a dispute with Exxon Mobil Corp. This threat caused a 2% increase in the price of crude oil.
Third: Burning fossil fuels dumps carbon dioxide and other pollutants into the atmosphere. The dumping of the pollutants is considered a fact. The severity of the damage to our atmosphere is still being debated, but most scientists believe that the future consequences will be very damaging to the quality and affordability of the lifestyles of our current and future generations.
Fortunately, renewable energies are accelerating into the forefront to replace fossil fuels, but will the replacement be in time? Germany has adopted wind and solar energies and is leading the world in the replacement of fossil fuels. These alternate fuels are quickly being adopted in many countries to help replace fossil fuels. These countries provide a blueprint for the USA to follow and in replacing its dependence on fossil fuels. The most popular replacements are wind and solar energy. Both of these technologies require us to rethink our energy policies.
There is a third leg available for the replacement of fossils fuels, geothermal energy. This type of energy offers us a potential to replace our coal fired electrical generating plants by 2050. It is available and being utilized today. It is the third leg of the tripod that we need to replace fossil fuels in time to retain our quality of life. What is Geothermal Energy?.
Geothermal energy is derived from the heat in the interior of the earth. Geothermal systems move the heat from the earth into the home in the winter and discharge heat into the ground in the summer. Underground piping serves as a heat source in the winter and a heat sink in the summer. In essence, it is the same heat-exchanging process used by the common refrigerator or air conditioner. Heat from the earth can be used as an energy source in many ways, from large and complex power stations to small and relatively simple pumping stations. Examples of this heat energy can be found almost anywhere. It can be found as far away as remote, deep wells in Indonesia and as close as our own backyard.
In the Western United States and in other places around the world, geothermal energy produces electricity in large power plants. Today, geothermal energy provides about five percent of California's electricity, and 25 percent of El Salvador's. In Idaho and Iceland, geothermal heat is used to warm buildings and other applications. In thousands of homes and buildings across the United States, geothermal heat pumps use the steady temperature just underground to heat and cool buildings, cleanly and inexpensively.
Physics of Geothermal Energy: Just a few meters below the earth's surface the temperature of the soil becomes rather constant. You can depend on this constant temperature throughout the seasons. You can extract this heat in the winter to heat your house or to "bury" your heat in the summer to cool your house. Trench-pipe systems are utilized in areas where ample space is available and well systems are utilized where there is limited space. It is within the trench or well system that "coolant" is circulated to deposit or extract the energy within the earth. As one can extrapolate, the further we reach into the earth the higher the temperature will be. We have a great understanding of the heat transfer parameters for all the zones of the United States. The physical parameters of this technology are beyond the scope of this paper, but past successes in design have demonstrated our ability to harness this energy. In addition, we can gain a great benefit from our oil companies. The technology successes that the oil companies have had in drilling for oil can now be applied to drilling for geothermal energy.
Great, How Much Will It Cost Us? An MIT study by MIT Professor Jefferson Tester et.al., The Future of Geothermal Energy, a study of the potential for geothermal energy within the United States, found that mining the huge amounts of heat that resides as stored thermal energy in the earth's hard rock crust could supply a substantial portion of the electricity the United States will need in the future, probably at competitive prices and with minimal environmental impact. It was their conclusion that geothermal energy could supply 10% of our electrical needs by the year 2050. This time frame could be accelerated if we, and our government, adopted a more aggressive schedule.
A conclusion from the MIT study ,mentioned previously estimates that a project costing $300 million US dollars to $400 million US dollars is needed to fund early generation plants. The same study cites a US government study of geothermal energy which estimates that for every 100,000 nominally sized residential units consumers will save approximately $500 million over a 20 year time span in heating and cooling cost at today's prices. This estimate was from a 1993 US Government report. Installation of a heat pump in a four-bedroom, 3,000 square foot house situated in the middle of the US would cost approximately $26,000.00. Payback at today's energy cost of $0.09 per kilowatt would be in the range of 13 to 14 years. Government incentives and home appreciation are not included in this analysis.
Summary: Geothermal energy is a tested and available renewable energy that can be utilized to replace fossil fuels today. Heat mining has the potential to supply a significant amount of the country's electricity currently being generated by conventional fossil fuel, hydroelectric and nuclear plants. The resolve to replace fossil fuels with geothermal, wind or solar is left to us and to our government. The technologies are available and ready to be deployed.
About the Author:
I have a BS and MS in Metallurgical Engineering. Thirty six years spent
in the development of semiconductors. Business experience in start up business
plan. Currently, an oyster farmer and interested in helping the environment
by deploying solar energy. Visit my Blog, http://environmentalhelp.typepad.com/
for continued information on renewable energy E Mail: p_calhoun@bellsouth.net