>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
>be done about it. Basically, there are two options – consume less,
>alternative energy sources to burning hydrocarbons, preferably
>ones. Geothermal energy is one possible alternative. So how much of
>energy consumption does it currently satisfy? What is its realistic
>and what are the technical challenges to maximizing that potential?
>green is it really, and is it truly renewable? Does it offer a free
>are there environmental costs in utilizing it? Are your tax dollars
>on these problems?
>Gillian R. Foulger, a full professor of Geophysics at University of
>U.K., and director of her own geothermal consultancy company, will
>some of the hottest geothermal issues, including an overview of how
>fascinating resource is utilized around the world, what direction
>is moving in, and what is going on in the US. Gillian has worked
>U.S. Geological Survey for over 20 years on earthquake seismology,
>surveying and geothermal energy. Her alter ego is leader of a
>on whether volcanic “hot spots” are underlain by deep mantle
Dr. Foulger began her talk by explaining that she graduated as a
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
who get 40% of their energy from this source. Worldwide, there are
Megawatts of electricity generated geothermally, with about 2,500
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
The Geysers was a huge provider of geothermal power as recently as ten
ago. When people started industrial scale power generating in the area
1960s there was only one big turbine running on the steam from a
That grew steadily to a peak in the late 1980s when the reservoir
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
Coso is the other big geothermal resource in California. It's the 7th
geothermal resource in the world, covering about 28 square kilometers.
It involves 177 wells, and is currently producing 300 Megawatts,
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
power out of the ground. One is to drill a deep well to mine heat
the magma beneath volcanoes. Dr. Foulger "wouldn't bet her pension on
that one", but considers it an interesting idea in the Chinese sense.
to put a coil under the ground in the yard, far enough below the
the temperature is fairly constant. With a heat exchanger it is energy
to get heat from there during the winter and sink heat there in
She said this kind of thing is becoming ever more common in