What
Is Geothermal Energy? Geothermal energy is the natural heat
of the Earth, which is transferred from the hot core of the
planet
to the
much cooler surface by conduction of heat through rocks. It is this same
heat that produces the molten lava, hot ash and gases
that we see spewing from an erupting volcano.
Geothermal
energy can be harnessed by modern technology and brought to the surface
as steam or hot water and converted to electricity.
Miles beneath the Earth's surface lies one of the world's largest energy
resources—geothermal energy. Our ancestors have used geothermal
energy for cooking and bathing since prehistoric times. Today, we use
this enormous energy reservoir to supply millions of people with clean,
low-cost electricity. Geothermal
power plants use wells to pipe steam and hot water trapped underground
to the surface to make electricity. The power plants produce electricity
at 5¢ to 7.5¢ per kilowatt-hour. The
Geysers Power Plant in northern California—the world's largest
geothermal power plant—generates more than 1700 megawatts of electrical
power. Geothermal power plants are highly reliably and can operate 24
hours a day. Most power plants operate more than 95 percent of the time.
Enhanced Geothermal Systems (EGS)
The accessible U.S. EGS resource base is enormous — greater than 13 million
quads or 130,000 times the current annual consumption of primary energy in the
United States.
Abundant
Power from Universal Geothermal Energy —An MIT chemical engineer explains why new technologies could finally make “heat
mining” practical nearly anywhere on earth. By Kevin Bullis
A comprehensive new MIT-led study of the potential for geothermal energy within
the United States has found that mining the huge amounts of heat that reside
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.
An 18-member panel led by MIT prepared the 400-plus page study, titled "The
Future of Geothermal Energy" (PDF, 14.1 MB). Sponsored by the
U.S. Department of Energy, it is the first study in some 30 years to
take
a new look at geothermal, an energy resource that has been largely
ignored.
The goal of the study was to assess the feasibility, potential environmental
impacts and economic viability of using enhanced geothermal system (EGS)
technology to greatly increase the fraction of the U.S. geothermal resource
that could be recovered commercially.
Although geothermal energy is produced commercially today and the United
States is the world's biggest producer, existing U.S. plants have focused
on the high-grade geothermal systems primarily located in isolated
regions of the west. This new study takes a more ambitious look at this
resource
and evaluates its potential for much larger-scale deployment...
Gene
Wescott, a geophysicist and Professor Emeritus at the University
of Alaska, Fairbanks has explored the possible use of geothermal
energy in
the Aleutian
Islands to produce hydrogen for use in clean automobiles.
...Several decades ago, when
the world was searching for new types of energy, Professor Wescott
was dispatched from his campus in Fairbanks to a long string of islands
that stretches
for 1,100 miles from Alaska into the northern Pacific Ocean. The
Aleutians
are volcanic islands, many of them quite active today, and they are
literally sitting on shallow beds of molten rock, surrounded by water.
The U.S. Department of Energy wanted to know if those desolate
islands could be used to produce geothermal energy. The idea was that
the hot areas beneath the surface might provide a continuous source
of blistering hot water, which could in turn be flashed to steam and
used to turn turbines and produce electricity. The precedent had been
set in California and Iceland. California draws a small percentage of
its electricity from geothermal power plants near San Francisco.
Energy for Centuries
So Wescott traveled out the Aleutians, drilling a few test wells
along the way, and he found just what common sense would suggest should
be there. The rocks beneath the surface were very, very hot.
.
.
.
But here's the hitch: Why build power plants hundreds, or thousands,
of miles away from any users? It isn't practical to run power lines
from the Aleutians all the way to the major population centers of the
western United States, so what Wescott really found was an enormous
source of energy where nobody could use it.
So the whole idea kind of died, except in the mind of Gene Wescott...
In recent years, Wescott has returned to the idea of building geothermal
power plants in the Aleutians, and using that electricity to produce
hydrogen. The hydrogen could be liquified, he says,
and shipped to Asia or the west coast of the United States. One of
the
largest geothermal resources he found in his earlier research is near
the major deepwater port of Dutch Harbor, making it almost seem
as though providence planned the whole thing.
By Lee Dye
Special to ABCNEWS.com Free
From Oil- Scientist Dreams of World Fueled by Hydrogen
The volcanic heat energy within the Earth's
Ring of Fire could provide human civilization with more energy than
all of the fossil fuels on the earth.
Experimental Geothermal Technology:
Hot dry rock goes supercritical:
Based on expertise gained during the development
of the Laboratory's Hot Dry Rock Project, Los Alamos geoscientist Donald
W. Brown has proposed a method for producing geothermal energy using supercritical
fluids such as carbon dioxide for the stimulation of the underground reservoir,
production of the geothermal energy and heat transport. The Hot Dry Rock
Project was a geothermal energy experiment that Los Alamos conducted between
the years 1970 and 1996.
Brown's process stimulates underground reservoirs
by pumping a supercritical fluid into a formation to fracture the rock.
Generally, this is done at depths ranging from about 5,000 feet to about
20,000 feet below surface depending upon underground thermal conditions.
At such depths, underground temperatures are in the range of roughly 200
to 600 degrees Fahrenheit in the western United States.
A supercritical fluid is a liquid that has
been raised beyond a temperature and pressure at which the liquid and
gas densities are equal -- its critical temperature and pressure. For
carbon dioxide, the supercritical conditions are a pressure of 1,074 pounds
per square inch and a temperature of 88 degrees Fahrenheit.
LOS ALAMOS, N.M., April 21, 2004
