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Coal probably accounts for close to 60-70%
of the historical and current World Power plants. Most countries have
invested several billions of dollars to acquire the infrastructure, the
technology and train the personnel for mining and processing electricity
from coal over years. Decommissioning the coal power plants will not be an
easy sell to such countries. Secondly there are still large deposits of
coal unused worldwide.
Some of the disadvantages of Coal as fuel for Power
Plants:
-
Coal fired plants release greenhouse gases (GHGs),
e.g. CO2 to the atmosphere as coal is burnt. The GHGs (particularly
CO2) have been shown to be responsible for fast changing climate resulting
in global warning and its several
effects and problems. Burning coal also releases other pollutants
(e.g. Sulphur Dioxide (SO2); Nitrogen Oxides (NOx), particulates (e.g.
mercury) etc) to the atmosphere. thus contributing to
global warming and having some other negative impacts on the environment.
-
Coal is a fossil fuel. It is
non-renewable. We will eventually run out of coal
supply. It is pertinent to look for alternative sources such as
solar, wind,
nuclear, geothermal,
biomass etc. to make our coal deposit and leave
some reserves for coming generations.
Clean Coal Technologies:
Some people are proposing Clean Coal
Technologies (CCTs), to ensure that we keep our old friendly coal plants
and still ensure that our environment is not negatively impacted. Clean
Coal technologies are technologies aimed at reducing the environmental
impacts from the use of coal for energy.
A cleaner production of energy from coal
will be favoured by most nations simply because the infrastructures are
already in place and all that may be required are upgrades to add the
cleaning components. This could avoid the very high costs of investing in
brand new technologies and decommissioning the coal plants.
Some of the CCTs proposed are:
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Chemically washing minerals and impurities
of coal prior to burning for energy;
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Gasification - converting carbonaceous
materials, such as coal, petroleum,
or biomass, into carbon monoxide and hydrogen by reacting the raw material
at high temperatures with a controlled amount of oxygen and/or steam,
resulting in a gas mixture called synthesis gas or syngas, which itself is
a fuel.
-
Treating the flue gas (smoke) from the coal
stove/furnace with steam to remove sulfur dioxide
-
Carbon Capture and Storage (CCS) systems
that could capture the carbon dioxide from the flue gas and store it up
underground permanently preventing its release to the atmosphere.
Obviously all the technologies above may
have to be employed in a single processing cycle.
The development of the CCTs mentioned above
(particularly the CCS) is still in an early stage. Demonstration plants
are being proposed everywhere to explore CCS and
other CCTs.
Other Sources of Information:
Wikipedia - Carbon Capture and Storage
Wikipedia - CO2 sequestration
Clean Coal Technology on Wikipedia
America's Power - Clean Coal
Government
of Alberta - Clean Coal Technology Fact Sheets
Clean
Coal technologies Inc.
Natural Resources Canada - Clean Fossil Fuels
World Nuclear Association - Clean Coal Technologies
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