[Sosfbay-discuss] Is There a Free Lunch Out There?

[Tian Harter]

 >Gillian R. Foulger, Ph.D.
 >
 >Is There a Free Lunch Out There? Geothermal Energy, its Potential
 >and Challenges as a Renewable, Alternative Energy Resource
 >
 >
 >As doom and gloom predictions from scientists about global warming
 >rise to a crescendo, there is increasing public demand to know what can
 >be done about it. Basically, there are two options – consume less, or find
 >alternative energy sources to burning hydrocarbons, preferably renewable
 >ones. Geothermal energy is one possible alternative. So how much of our
 >energy consumption does it currently satisfy? What is its realistic 
potential,
 >and what are the technical challenges to maximizing that potential? How
 >green is it really, and is it truly renewable? Does it offer a free 
lunch, or
 >are there environmental costs in utilizing it? Are your tax dollars at 
work
 >on these problems?
 >
 >Gillian R. Foulger, a full professor of Geophysics at University of 
Durham,
 >U.K., and director of her own geothermal consultancy company, will present
 >some of the hottest geothermal issues, including an overview of how this
 >fascinating resource is utilized around the world, what direction 
technology
 >is moving in, and what is going on in the US. Gillian has worked with the
 >U.S. Geological Survey for over 20 years on earthquake seismology, GPS
 >surveying and geothermal energy. Her alter ego is leader of a global 
debate
 >on whether volcanic “hot spots” are underlain by deep mantle plumes.

Dr. Foulger began her talk by explaining that she graduated as a
geophysicist back in the '70s. Her first work in the field was in Iceland,
where she made some remarkable discoveries of geothermal resources.
Since then she has been a leading expert in the field. She has since worked
in England, Iceland and the US, often in settings where brilliant grad
students were part of the team.

Worldwide, one of the biggest users of geothermal resources are the 
Icelanders,
who get 40% of their energy from this source. Worldwide, there are about
9,000 Megawatts of electricity generated geothermally, with about 2,500
Megawatts of that being generated in the USA. Of America's piece of the
pie, 2,200 Megawatts are generated in California. Most of California's 
power
comes from The Geysers, a geothermal area near Santa Rosa that is as 
unique,
just as Hawaii is unique as a volcanic area. Most of the rest of 
California's
geothermal electric contribution comes from Coso, a geothermal area in the
Owens Valley.

The Geysers was a huge provider of geothermal power as recently as ten
years ago. When people started industrial scale power generating in the 
area
in the 1960s there was only one big turbine running on the steam from a
well. That grew steadily to a peak in the late 1980s when the reservoir
pressure reduced to alarmingly low levels.

The problem was that there were many small producers, and each of them
had an incentive to use more of the steam than anybody else. Since then the
Calpine Corporation has taken over management of the whole area, and has
got things under better control. Now about 1,200 Megawatts are generated,
and the resource is expected to last for several decades more, at which
time much of the fluid will have been mined out of the rocks.

Coso is the other big geothermal resource in California. It's the 7th 
largest
geothermal resource in the world, covering about 28 square kilometers.
It involves 177 wells, and is currently producing 300 Megawatts,
supplying electricity to about a million people. This one is being depleted
at a much slower rate than The Geysers. Dr. Foulger had good things to
say about the way the U.S. Navy is running this facility, which it owns.
So far they have got $4 billion worth of power out of it for a
$1 billion investment and are managing it wisely to maximize its potential.

Looking to the future, there are various possible ways to get geothermal
power out of the ground. One is to drill a deep well to mine heat 
directly of
the magma beneath volcanoes. Dr. Foulger "wouldn't bet her pension on
that one", but considers it an interesting idea in the Chinese sense. 
Another
is to put a coil under the ground in the yard, far enough below the surface
that the temperature is fairly constant. With a heat exchanger it is energy
efficient to get heat from there during the winter and sink heat there in
the summer. She said this kind of thing is becoming ever more common in
Europe.

-- 
Tian
http://tian.greens.org
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