Archive for March 10th, 2010

Science & Soul: Clean Coal My Butt

I have been very busy and have not had time to post or read others’ blogs.  Sorry ’bout that.

Clean coal technology  aims to permanently capture and isolate carbon dioxide gas resulting from coal combustion so that it does not

contribute to global warming. The most promising method of sequestering carbon dioxide is carbon capture and storage. The coal must

undergo gasification to remove the carbon dioxide before combustion. In this process, the coal is exposed to steam at high pressures and

temperatures, producing syngas, a mixture of carbon monoxide, carbon dioxide, hydrogen gas, and methane. This syngas then reacts

with chemical scrubbers which isolate and capture the carbon dioxide.  This captured carbon dioxide is then transported and injected into

either underground or ocean waters. Unfortunately, clean coal does not exist. There are far too many environmental and economic

problems associated with the burning of coal, whether it be considered conventional or clean.

Clean Coal process

The fastest and most cost-efficient method of obtaining coal in many situations, depending on the depth and location of the coal, is to
simply remove the overburden. In some cases, this requires mountaintop removal. This involves blasting the summit of a mountain with
explosives and pushing the excess soil and rock aggregate into surrounding valleys so that miners can remove the coal deposits.  Despite
precautions, this form of mining is extremely destructive to the environment.  Mountaintop mining operations often fill in the streams
surrounding the mountain they are excavating.  This leads to an increase in mineral levels and acidification of water due to chemical
runoff from the mine causes a decrease in aquatic biodiversity in the surrounding region. Many native aquatic organisms cannot adapt to
the change in stream chemistry rapidly enough and die as a result. Biomagnification in the aquatic food system causes the
aforementioned toxic chemicals to accumulate in any organisms living down-stream of the mines.  This has caused a number of
documented reproductive mutations in fish. Furthermore, these fish are considered unsafe for human consumption because of the levels
of chemicals in their tissues.  Mountaintop removal also endangers human health.  Residents near such mining operations face a sixty-four
percent higher risk of respiratory diseases like bronchitis and emphysema. Scientists believe that these illnesses are caused by the coal
dust that often rains down on towns while mining companies blast the nearby mountains. This dust consists of many toxic impurities
which cause further medical problems for humans.

An example of mountaintop removal.

Even when sequestered, there remains a possibility that the carbon dioxide will leak out of the soil or waters and back into the
atmosphere.  If even a portion of this carbon dioxide escaped, the benefits of carbon dioxide sequestration would be mitigated. Also,
carbon dioxide leaks could be potentially lethal.
The largest cost associated with this technology is retrofitting previously built coal burning plants with clean coal
carbon sequestration facilities. This major undertaking is prohibitively expensive.  Once running, clean coal technology would have to be
maintained, causing a doubling in costs, which would then effect prices.  Based on the amount of carbon dioxide produced from burning
coal, governmental agencies estimate that the total cost of building and maintaining such systems in the United States amounts to
approximately sixteen billion dollars per year.
Clean coal is an oxymoron. It can only be viewed as “clean energy” when one does not take into account a rising number
of environmental and social costs associated with burning fossil fuels for power, including mountaintop removal, carbon dioxide leakage,
and restrictive costs. Using carbon dioxide capture and storage may decrease our carbon emissions, but only perpetuates our
dependency on nonrenewable fossil fuels.  We must stop trying to find ways to extend our use of nonrenewable energy sources and instead
revitalize our search for more efficient and sustainable power supply.  The solution is not reducing wastes associated with fossil
fuel combustion, but rather living within our means and curtailing our own wastes and inefficiencies.
Falkowski, T. B. Clean Coal: An Environmentally and Economically Expensive False Hope. Binghamton University. Web. 10 Mar.

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