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A Hot Future for Geothermal |
Co-Written by Marin Katusa & Marc Bustin,
Editors of
Casey’s Energy Report
Capturing energy from the earth’s heat is
pretty easy pickin’s for geologically-active areas of the world like
Iceland, Indonesia, and Chile. In some locations, hot fluids are so
near the earth’s surface that heat from naturally-occurring hot fluids
can be directly circulated through buildings for heating. Iceland, in
particular, takes advantage of this low-hanging energy fruit.
However, in most areas of the world where
geothermal energy is captured, the heat is used to generate
electricity.
Conventional Geothermal Energy
Unlike some of the more common alternative
energies — hydro, solar, and wind — geothermal is impervious to
weather conditions. This independence means it provides excellent base
load electricity.
Currently all commercial geothermal
electricity is generated by so-called conventional systems, whereby
naturally- occurring hot water or steam is accessed at comparatively
shallow depths in areas of very high geothermal gradient. Wells are
commonly drilled to depths on the order of 2 km. The water or steam
they produce is used to spin turbines that in turn generate
electricity.
The success and sustainability of a
geothermal reservoir in large part depends on managing the reservoir.
For a reservoir to be sustained, the natural and induced recharge of
fluids must balance the produced fluids. Almost all reservoirs require
the produced water to be re-injected in order to maintain reservoir
pressure. Because naturally-occurring water and steam are necessary,
potential development is generally restricted to areas near volcanic
activity.
But the geographic limitations of geothermal
energy may be about to change — and create a much rosier picture for
the future of geothermal energy.
Enhanced Geothermal Systems (EGS)
Conventional geothermal systems are possible
only in relatively limited geographic areas. The real prize in
accessing geothermal energy – and at a much larger scale – is through
enhanced (or engineered) geothermal systems.
In EGS, hot rocks are artificially
fractured, commonly at great depths. Water is injected to contact the
hot rocks and then produced back to the surface; the energy captured
is used to generate electricity. These are very expensive ventures,
with costs in excess of $10 million dollars as a starting point — ten
times the cost of a geothermal well. Current EGS projects are still
experimental, and most have substantial government backing.
A relatively advanced EGS experimental
system is currently underway in Australia. Here, granites producing
high heat due to radioactive decay at depths greater than 3 km are
seen as viable geothermal reservoirs. In South Australia alone, some
23 companies have filled licenses covering 110,000 sq km where
suitable hot granite is believed to exist at accessible depths.
Once such a plant is built, it will be
tapped into a virtually limitless supply of energy that’s available
without cost, 24/7. Successful implementation of EGS plants will be
the break-out technology for geothermal energy.
Is Geothermal Economically Viable?
A workable technology is one thing, and
economic viability is something entirely different. As you can see
from the chart below, not all energy sources are created equal when it
comes to cost per kilowatt-hour.
In terms of production cost, geothermal
certainly holds its own at 6.5 cents per kilowatt-hour — about the
same as wind. Coal and nuclear power are still powering the way ahead
with their 4-5 cent/kWh generation costs, but with natural gas at 7
cents and petroleum topping 10, geothermal has already proven itself
to be a viable alternative, not only on the economic front but on the
environmental front as well.
In terms of current worldwide energy
production, geothermal — along with solar — is a drop in the bucket:
Given the fact that geothermal energy is
only a minor player in the worldwide picture for energy, why are we
still bothering with it?
Because in terms of economics, geothermal
energy trounces solar and wind.
Here's what we mean:
1. Geothermal energy does not depend on
weather. The sun doesn't shine around the clock or even every day;
neither does the wind blow all the time. In contrast, hot rocks are
there 24 hours of the day, seven days a week. The predictable amount
of electricity makes it easy for geothermal companies to sign
long-term energy contracts without worrying as much about
underproduction or "wasted" production.
2. Lower capital costs. Even though solar
panels have gotten much cheaper to make, the construction costs of a
large solar farm are still extremely high. Recent estimates place
the cost of solar energy to be upwards of US$10,000 per
kilowatt-hour (kW) whereas wind is around $1,700-$3,000/kW.
Geothermal is similar to wind at US$1,600-$2,800/kW depending on
location, though due to reasons 1 and 3, geothermal is economically
superior to solar and wind. In fact, these numbers put geothermal on
par with building a coal plant under the new requirements for carbon
capture.
Geothermal capital costs are relatively
low for two reasons. First, there's no need to sequester, or capture
and stash, any carbon emissions. This requirement alone can add
40-60% to fossil fuel projects. Second, geothermal power plants
enjoy the best of both worlds: they require less land than wind and
solar projects, and fewer permits than coal and nuclear because
they're less hazardous.
3. Higher load factor. Utility companies,
and anybody buying power from them, have to consider load factor:
the difference between nameplate capacity (how much the generator is
designed to produce) and actual production. The smaller the
difference, the higher the load factor, and the more money the
utility will make. For a wind farm, the load factor is generally
30-40%, and even lower for solar farms. In contrast, geothermal
power plants can generally operate near 90%, since, as we said
before, hot rocks are always available.
On an economic basis, geothermal has a
virtually unique advantage among the "green" energies. Its power
plants can compete with those fired by coal or natural gas even before
any government subsidies. For geothermal operating companies in the
United States, the government subsidies that Obama is showering upon
the alternative energy sector are pure icing on the cake.
And best of all, geothermal companies are
virtually off the radar of most investors. For those keeping an eye on
geothermal technology and geothermal companies, a window of great
opportunity will open.
This kind of research is typical of
Casey’s Energy Report and its research team, led by Marin
Katusa. And with a stock pick record of 19 winners in a row — a 100%
success rate over 11 months — Marin’s insightful research has made a
great deal of money for his subscribers.
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