The Plus Side of Volcanoes
The Earth's crust, on which we live and depend, is in large part the product of millions
of once-active volcanoes and tremendous volumes of magma that did not erupt but
instead cooled below the surface. Such persistent and widespread volcanism has resulted
in many valuable natural resources throughout the world. ... Groundwater heated by
large, still-hot magma bodies can be tapped for geothermal energy. -- Excerpt from: Brantley,
1994, Volcanoes of the United States, USGS General Interest Publication
The internal heat associated with young volcanic systems has been harnessed to
produce geothermal energy. For example, the electrical energy generated from The
Geysers geothermal field in northern California can meet the present power consumption
of the city of San Francisco. -- Excerpt from: Tilling, 1985, Volcanoes: USGS General Interest
Publication
Geothermal energy can be harnessed from the Earth's natural heat associated with
active volcanoes or geologically young inactive volcanoes still giving off heat at
depth. Steam from high-temperature geothermal fluids can be used to drive turbines and
generate electrical power, while lower temperature fluids provide hot water for spaceheating purposes, heat for greenhouses and industrial uses, and hot or warm springs at
resort spas. For example, geothermal heat warms more than 70 percent of the homes in
Iceland, and The Geysers geothermal field near Santa Rosa, in Northern California
produces enough electricity to meet the power demands of San Francisco. The Geysers
area is the largest geothermal development in the world. In addition to being an energy
resource, some geothermal waters also contain sulfur, gold, silver, and mercury that can
be recovered as a byproduct of energy production. -- Excerpt from: Kious and Tilling, 1996, This
Dynamic Earth: The Story of Plate Tectonics: USGS General Interest Publication
Kilauea, Hawaii
In recent years, volcanic energy has been harnessed by a geothermal power plant on
Kilauea's east rift zone; the three megawatts of electricity produced are fed into the grid
of the local utility company. Much larger capacity geothermal development is under
discussion. -- Excerpt from: Tilling, Heliker, and Wright, 1987, Eruptions of Hawaiian Volcanoes: Past,
Present, and Future: USGS General Interest Publication
Newberry Caldera, Oregon
Geologically young volcanoes found in our area suggest that central Oregon may
contain some of the best prospects for geothermal exploration in the continental United
States. One study done at Newberry Volcano estimated the energy potential to be up to
13,000 megawatts. Another study by Bonneville Power Administration estimates a
16,000 megawatt potential. -- Information courtesy USFS, Deschutes National Forest Website, 2000
The Geysers, California
The Geysers geothermal field near Santa Rosa, in Northern California produces
enough electricity to meet the power demands of San Francisco. The Geysers area is the
largest geothermal development in the world. -- Excerpt from: Kious and Tilling, 1996, This
Dynamic Earth: The Story of Plate Tectonics: USGS General Interest Publication
Gravity and teleseismic studies suggest that a large silicic magma chamber,
approximately 14 kilometers in diameter, lies 7 kilometers and deeper beneath the (Clear
Lake) volcanic field. This reservoir is thought to be the heat source for the Geysers
geothermal field (on the southwest side of the volcanic field), which is the largest
producing geothermal field in the world, with installed electrical generating capacity of
around 2,000 megawatts in 1988, enough electricity for about two cities the size of San
Francisco. -- Excerpt from: Wood and Kienle, 1990, Volcanoes of North America: United States and
Canada: Cambridge University Press, 354p., p.226-229, Contribution by Julie M. Donnelly-Nolan
Casa Diablo, Long Valley Caldera, California
Wells drilled at Casa Diablo, on the southwest side of Long Valley's resurgent dome,
tap into the caldera's hydrothermal system by pumping hot water at temperatures near
170 degrees C to supply three geothermal power plants that generate about 40 megawatts
of electricity. Cooled geothermal water from the plants is injected back underground. -Courtesy of: U. S. Geological Survey's Long Valley Monitoring Project - Hydrologic Studies, 1997
Salton Sea Geothermal Field, California
The Salton Buttes lie within the Salton Sea geothermal field, where temperatures at 1.5
to 2.5 kilometers reach 360