After Stab in the Back, Geothermal Poised for a Comeback

Whenever alternative energy is mentioned, solar and wind energy come most immediately to mind. Yet as promising as the futures for these energies may be, most Americans may not be aware that geothermal energy has been extensively utilized in the past and present. Moreover, its future appears to be virtually unlimited and initial capital outlay for its development might well be the most cost-effective of all alternative energy sources.

In a story that received very little media coverage at the time and even less coverage when the Bush Administration pulled funding for geothermal research shortly after, the Massachusetts Institute of Technology (MIT) released a study concluding that a proposed form of geothermal extraction they referred to as “heat mining” could “provide a substantial portion of the electricity that the United States will need in the future.” Furthermore, the MIT study concluded that “heat mining” could do so “probably at competitive prices and with minimal environmental impact.”

The report, entitled The Future of Geothermal Energy was prepared by an 18 member MIT team and sponsored by the US Department of Energy. It was the first comprehensive government study of geothermal energy in 30 years.

Director of the MIT panel, Professor Jefferson W. Tester, stated that that panel had “determined that heat mining can be economical in the short term..” that “EGS (Enhanced Geothermal System) technology has already been proven to work in the few areas where underground heat has been successfully extracted..” and that “further technological improvements can be expected.”

Ignoring a verbal commitment to an expansion of alternative energy development, the Bush Administration not only ignored the MIT panel recommendations but pulled remaining geothermal specific research monies. Despite the blow to incurred to further geothermal research and development, geothermal energy usage is far more prevalent than is generally understood.

The term geothermal is derived from the Greek words geo, meaning earth and therme which refers to heat. It is one of the few known sources of energy not directly or indirectly related to the sun. Geothermal heat is generated almost entirely from the release of heat caused by the decay of radioactive elements deep within the earth and not remnant heat from the planet’s formation. It has been said that because he did not understand that the earth’s internal heat was caused by natural radioactive decay that Charles Darwin died believing he was wrong about the age of the earth and quite possibly evolution.

Due to the presence of hot springs and volcanoes, mankind has long been aware that the interior of the earth must be quite hot. The first mines that achieved significant depth confirmed that impression. Every 328 feet of depth the ground temperature rises an average of 5.4 degrees. In most places at 10,000 feet water boils, the key to geothermal energy.

It wasn’t until 1904, however, that geothermal energy first produced electricity at Lardello, Italy and by 1942 Lardello was producing 127 megawatts of power, almost all of the power used by the Italian railway system. Other early geothermal facilities included Japan (1919), the Geysers in California in 1921, Iceland (1928), New Zealand (1958) and Mexico (1959).

In the US as far back as 1892 the citizens of Boise, Idaho made use of that area’s substantial geothermal resources to create the first district wide geothermal heating system in the United States. A comprehensive look at the Boise system is found in the 1987 Geological Society of America’s Centennial Field Guide – Rocky Mountain Section featured an article entitled “Geologic framework of the Boise Warm Springs geothermal area, Idaho by Spencer H. Wood and Willis L. Burnham, professors of Geology and Geophysics at Boise State University in Boise.

According to Burnham and Wood the first two geothermal wells were drilled to a depth of approximately 400 feet, were strongly artesian (under pressure), flowing at a rate of 550 gallons per minute at a temperature of 170-175 degrees Fahrenheit.

Over 250 homes and quite a few buildings including the Idaho Water Center. Long standing users of the geothermal district are billed $400 per year, while newer users still see savings over natural gas and other heat sources.

The district recommends that customers along the distribution line extract at least 50 degrees of heat using heat exchangers to achieve the maximum savings over natural gas. In 1987 those costs were 20 cents per 100,000 BTU for geothermal heat versus 36 cents with natural gas, almost a 2-1 margin. The State of Idaho Capitol Mall system is served by other, deeper wells.  A quick look at the geological history of the Boise area is instructive in terms of the tremendous potential of geothermal energy.

Interestingly two of the major “hot spots” in the earth’s crust, including the largest are located in the United States. An interesting aside is that, for unknown reasons, satellites actually dip in their orbits when passing over either hot spot. The first hot spot is the big island in the Hawaiian island chain. A look at the island chain itself demonstrates how that hot spot has moved over geological history, to the south and east.

The other “hot spot,” the Yellowstone hot spot has also moved south and east over geological time, having been recently (in geological terms) located in Idaho. Geologists believe that the Yellowstone hot spot, located below the Yellowstone caldera, an area that encompasses most of Yellowstone National Park, is sitting atop the “world’s largest volcano.” Unsettlingly, geologists believe that the volcano remains active, though fortunately eruptions can be thousands of year apart. More unsettlingly, geologists believe that a major eruption of the Yellowstone volcano is capable of bringing about a “nuclear winter” scenario. A herd of a now-extinct type of rhinoceros were killed by the eruption of the Yellowstone hot spot volcano at a time when the hot spot was located in what is now Idaho.

Due to the fact that the western US is more geologically active than other parts of the US, geothermal energy is more readily accessible here. California alone has 30 geothermal power plants which account for approximately 90% of the nation’s current geothermal production. Nevada has about 15 including a facility that travelers can easily see from Interstate 80 that is used for drying onions by a farmer’s cooperative. In addition to these states and Idaho, Colorado, Utah, Hawaii and a handful of other western states make at least some use of geothermal but the MIT report makes clear that the US is very far from realizing its true potential.

While geothermal research languished during the Bush Administration, there have been hopeful signs from the Obama Administration. In March, Interior Secretary Ken Salazar created a special task force, the Departmental Task Force on Energy and Climate change, which is tasked with identifying public lands which might prove useful as sources for renewable energy projects. According to a posting by Gina-Marie Cheeseman on care2.com, the Department of Interior has identified about 21 million acres with the potential for wind energy production, 29 million acres (primarily in the Southwest) with a solar energy potential and an astonishing 140 million acres with a geothermal potential, located mostly in the western states and Alaska.

It is the unique geology of the western states(and Alaska) and nations such as Iceland, Italy, Japan, Mexico and New Zealand that lend themselves to economical large scale geothermal projects. Interestingly, however, every residence in the United States (or the world) that has contact with the ground has the potential for an efficient use of geothermal energy. That is because at the depth of approximately 9 feet the temperature of the ground is always at around 50 degrees Fahrenheit. A system that employs a circulation of anti-freeze or similar fluid and a heat exchanger goes a long way towards using geothermal heat to heat the home in the winter and cool it in the summer.

In winter heat from the warmer ground goes through the heat exchanger of a heat pump which sends warm air into the home. In the summer, the process is reversed. Then hot air from inside the home or building goes through a heat exchanger and the warm air is either pumped into the colder ground or, better still, used to heat water.

A handful of contractors are already retrofitting existing homes using this technology and, hopefully, homebuilders will incorporate this technology in the construction of new homes in the future.