Basic HTML Version
FORTOMORROW
by
Robert A. Ginskey
A
nergy prices soar and re–
erves dwindle, the indus–
trialized world is coming
under increasing pres–
sure to find new ways of
providing the energy on which our
society depends. Solar power, wind
energy, refuse burning, alcohol and
methane production all show prom–
ise, but each is not without its limita–
tions and disadvantages.
One source of future power being
given serious consideration is geo–
thermal energy.
About 20 miles below the crust of
the earth, there exists a hot molten
mass called magma.
Tn
sorne placcs
the magma is relatively close to the
surfacc (five to ten miles down). rn a
geothcrmal field, water trapped in
fractures in the near-surface rocks is
heated by the magma. This results in
hot water and steam, which often can
escape along fractures to the surface
of the earth. Usually the steam is
undcr considerable pressure, and
when such a reservoir is tapped by
drilling, the steam can be used to
drive a turbine.
Actually, geothermal energy is not
new. Roman documents 2,000 years
old tell of a steam field west of what
is now Florence, Italy. Today, Italy
produces sorne 4,000,000 kilowatts of
geothermal electricity.
The United States has the largest
geothermal steam system in the
world, located about 90 miles north
of San Francisco. Known as the
Geysers Power Plant, it currently
produces nearly 1,000,000 kilowatts
of electrical power and may eventu–
ally double that capacity.
Since the fue! for geothermal
power is free, the cost of producing
electricity from it is only that of tap–
ping the steam and maintaining the
equipment. Total operating cost (fue!
plus capital) for geothermal electrici–
ty at the Geysers plant is well below
22
nuclear power, coal, and fuel oil.
Each 100,000 kilowa tts of geo–
thermal energy replaces one million
barreis of oil per year. Since the
Geysers plant may eventually pro–
duce 2,000,000 kilowatts of electrici–
ty, sorne 20 million barreis of oil
could be saved each year ata mone–
tary savings of about half a billion
dollars per year.
However, geothermal energy does
have severa! drawbacks. First, fairly
pure steam from the earth is quite
rare. The less useful hot water (with
more impurities) is much more com–
mon, but steam is far more desirable.
Also, almost all the geothermal
sources worldwide have the noxious
odor of hydrogen sulfide gas asso–
ciated with them. Special equipment
must be used to reduce thc hydrogen
sulfide odor where geothermal plants
are located near inhabited areas.
In spite of these difficulties, geo–
thermal power does have many ad–
vantages. Unlike power plants fueled
with coal, oil or natural gas, there are
no combustion products emitted to
contribute to air pollution and smog.
There are no long-lived and danger–
ous waste products as in the case of
nuclear power.
Moreover, fossil fuels and nuclear
fuels, diminishing in supply, are rapidly
increasing in cost; bycontrast, thesteam
of geothermal plants appears virtually
inexhaustible. Unlike hydroelectric
power plants, geothermal plants do not
require that rivers
be
dammed. Con–
densed steam from the geothermal sys–
tem can be recycled in the cooling pro–
cess and reinjected underground into
the steam reservoir.
Geothermal resources are not the
total answer to man's energy de–
mands, but in an increasingly ener–
gy-hungry world, geothermal power
willtmdoubtedly make a lasting con–
tribution to energy needs in the world
of tomorrow. o