10/01/2008 11:10 AM

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World Geothermal Energy Nearing Eruption Page 1

by Jonathan Dorn

With fossil fuel prices escalating and countries searching for ways to reduce oil dependence and greenhouse gas emissions, capturing the earth's heat for power generation is garnering new attention. First begun in Larderello, Italy, in 1904, electricity generation using geothermal energy is now taking place in 24 countries, 5 of which use it to produce 15% or more of their total electricity.

In the first half of 2008, total world installed geothermal power capacity passed 10,000 megawatts (MW) - enough electricity to meet the needs of 60 million people, roughly the population of the United Kingdom. In 2010, capacity could increase to 13,500 MW across 46 countries - the equivalent to 27 coal-fired power plants.

Originating from the earth's core and from the decay of naturally occurring isotopes such as those of uranium, thorium, and potassium, the heat energy in the uppermost six miles of the planet's crust is vast - 50,000 times greater than the energy content of all oil and natural gas resources.

Chile, Peru, Mexico, the U.S., Canada, Russia, China, Japan, the Philippines, Indonesia, and other countries along the Ring of Fire (an area of high volcanic activity encircling the basin of the Pacific Ocean) are rich in geothermal energy. Another geothermal hot spot is the Great Rift Valley of Africa, which includes such countries as Kenya and Ethiopia. Worldwide, 39 countries with a cumulative population of over 750 million people have geothermal resources sufficient to meet all their electricity needs.

Typically, power generation using the earth's heat requires underground pockets of high-temperature water or steam to drive a steam turbine. Now, new technologies that use liquids with low boiling points in closed-loop heat exchange systems allow electricity to be generated at much lower temperatures. This breakthrough is making geothermal power generation viable in countries such as Germany that are not known for their geothermal resources and is one reason why the number of countries using the earth's heat to generate electricity could almost double by 2010.

One advantage of geothermal power plants, beyond the benefit of producing electricity from a low-carbon, indigenous energy source with no fuel costs, is that they provide base-load power 24 hours a day. Storage or backup-power is not required.

The U.S. leads the world in geothermal energy production with nearly 2,960 MW across seven states - Alaska, California, Hawaii, Idaho, Nevada, New Mexico, and Utah. California, with 2,555 MW - more than any country in the world - produces almost 5% of its electricity from geothermal energy. Most of this capacity is installed in an area called the Geysers, a geologically active region north of San Francisco.

Thanks to the Energy Policy Act of 2005, which made geothermal power generation eligible to receive the federal renewable energy production tax credit, electricity generated from geothermal resources costs the same as fossil-fuel-based electricity in many markets in the western U.S. With favorable economics, the geothermal industry is experiencing a surge in activity.

As of August 2008, some 97 confirmed new geothermal power projects with up to 4,000 MW of capacity are under development in 13 states, with some 550 MW in the construction phase. Expected to create 7,000 permanent full-time jobs, the new capacity will include numerous large-scale projects such as the 350 MW and 245 MW projects by Vulcan Power near Salt Wells and Aurora, Nevada; the 155 MW project by CalEnergy near the Salton Sea in southern California; and the 120 MW project by Davenport Power near the Newberry Volcano in Oregon.

Current development is only scratching the surface of what is possible. The U.S. Department of Energy estimates that with emerging low-temperature technologies, at least 260,000 MW of U.S. geothermal resources could be developed. A study led by the Massachusetts Institute of Technology indicates that an investment of roughly $1 billion in geothermal research and development over 15 years (roughly the cost of a single new coal-fired power plant) could lead to commercial deployment of 100,000 MW by 2050.

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