As people become more aware of its environmental and cost benefits,
geothermal technology is fast becoming a popular alternative to
oil, gas or electric home heating. As well, industrial and commercial
complexes, and geothermal power plants, are finding this technology
a viable solution to rising energy costs: both economic and environmental.
What is it?
The earth is a giant solar collector, absorbing and accumulating
energy from the sun. This heat is stored in the earth's crust
where it remains a constant temperature. The depth at which the
temperature remains constant (below the frost line) varies from
local to local, but on average, this thermal "blanket"
is only a couple of feet below the earth's surface.
Other sources of geothermal heat, stored in underground aquifers and in geothermal
fluids such as Hot Springs or geysers, are used to generate
electricity. Eliminating the need for coal, oil or nuclear energy
sources, one geothermal power plant can supply a small city
or a large industrial complex.
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Your home
According to Natural Resources Canada (NRCan), "It is more
efficient to use earth energy as it requires less energy to
move heat from one place to another than it does to convert
one kind of energy to another, which is what a furnace does."
For Canadians, who use one-quarter of their total energy consumption
on space and water heating and cooling, switching to geothermal
could have a big impact on the future use of their natural resources.
As well, geothermal fluids can be used to heat buildings
with no conversion as seen in northern communities around
the world. They have used geothermal heat sources for centuries,
and this knowledge has not been lost in the move into the
modern age. The marriage of modern technology to old tradition
has resulted in geothermal fluids being piped under roads
to melt ice from the pavement, and has it radiating heat throughout
their homes.
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How they work
Ground
source heat pumps draw geothermal heat out of the ground by circulating
a solution of water and anti-freeze through a series of virtually
indestructible plastic tubing embedded in the subsoil under and
around your home. This tubing is inserted either vertically or
horizontally into the ground, literally "tapping" into
the geothermal energy contained within. The extracted heat energy
then flows back through a water-heat exchanger, where it is absorbed
by a refrigerant.
The
refrigerant is then compressed, increasing its temperature to
160°F, and an air-heat exchanger circulates it throughout
your home. By simply reversing the process, ambient heat can
be removed, and you are left with a cool, dehumidified interior.
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Environmental concerns
When asked what the potential impacts of having many kilometers
of tubing containing an anti-freeze buried into the ground, Bill
Eggertson of the Earth Energy Society of Canada (EESC), stated
that "no firm research has been done."
However, he went on to say that in the unlikely event a break
or hole occurred in the loop of tubing, the pressurized system
would "automatically stop pumping". He further explained
that the anti-freeze is really just a 20 per cent volume of
methyl alcohol, which is not currently considered an environmental
threat.
In Ontario though, Eggertson advised, the government elected
to restrict the use of methanol as it poses a potential hazard
to the safety of drinking water were it to be present in concentrated
amounts. Instead Ontario's geothermal systems use ethanol -
commonly known as "booze" and "at worst"
he said jokingly, "might only get your cat slightly drunk"
were a leak to happen.
The chance of a leak large enough to contaminate a drinking
water supply occurring is seen to be remote by the EESC, so
remote says Eggertson that "the legislation is unnecessary."
Commercial complexes
The mechanism for commercial buildings is identical to that
of residential, the only difference being the size and number
of pumps, and the volume of tubing. 
Many large hotels, government buildings and residential complexes
throughout the developed world have incorporated geothermal
heating and cooling systems - most realizing their investment
within a 3 -5 year period.
So far, there are few reports of this technology functioning
at substandard levels as compared to other heating and cooling
systems. In fact, there are fewer problems associated with geothermal
systems.
Not being connected to the national energy grid, they can operate
24-7, with no dysfunction as a result of an interruption in
power supply. Their maintenance requirements are less and their
life span longer. They also reduce dependency on foreign and
domestic oil supplies.
Power plants
The economic value of geothermal power plants has become increasingly
understood by industry and governments, and their continued
research and development of this technology indicates they believe
it to be a possible long-term solution to future energy and
fossil fuel shortages.
The U.S. Department of Energy (DOE) cites geothermal energy
is currently providing more than 2700 megawatts of electric
power to U.S. residents, comparable to 60 million barrels of
oil per year - enough for 3.5 billion homes. And, they say,
this is only a small fraction of the potential value of geothermal
energy available.
This displacement may also help to offset the urgency to develop
non-viable American oil fields such as the Alaskan Refuge.
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