Coal: Global Warming’s Biggest Scapegoat
Coal has been deemed the dirtiest of all fossil fuels emerging as the leading contributor to greenhouse gas emissions and global warming. When coal is burnt, it releases emissions of carbon dioxide, sulfur dioxide, nitrogen oxide, and other harmful emissions such as mercury that are then released via flue gas—the clouds that rise out of smoke stacks. These emissions have a direct impact on global warming, contribute to approximately 24,000 premature deaths a year in the United States alone, and can harm areas thousands of miles away via acid rain. Even the process of retrieving coal has its flaws—entire mountaintops are removed in search for large quantities, and the coal mining process can be highly hazardous. However, due to its relatively easy access, large quantities, and low cost relative to other energy sources, coal is likely to remain a power source for the foreseeable future.
What is clean coal?
Due to heavy protest and concern, the coal industry with help from scientists and politicians has revamped its image with ‘clean coal’ technology. An oxymoron of a term, Al Gore once said, “Clean Coal is like a healthy cigarette, it doesn’t exist.” Clean coal has been manipulated to mean anything that the industry wants it to mean, but it certainly does not mean carbon-free. Not a single coal fired power plant is emissions free, and almost none can do anything about carbon dioxide emissions, one of the leading proponents of global warming. However, it is good to look into the technologies because many are at least slightly better than burning dirty coal, and it is important to see which ones are most worth the investment. There are four main categories of clean coal technology:
Coal Washing: Literally what its name suggests. Crushed coal is washed prior to its burning so as to lower the level of sulfur and minerals within the coal.
Pollution Control Methods: There are several types of pollution controls that are each designed to control a particular type of emission. Electrostatic Precipitators can be installed to reduce particulate matter pollution, NOx burners reduce NOx emissions, and flue gas desulphurization can reduce SO2 emissions. Flue gas desulphurization, also known as scrubbing, has become a commonly used procedure in coal-fired power plants. Scrubbers are installed in the smokestacks of power plants where they then remove sulfur from the flue gas by using a sorbent—usually lime or limestone. It remains one of the most commercially used emission control methods and can easily be installed into existing plants.
Efficient Combustion Technologies: These involve improving the overall efficiency of the coal burning process. For example, Supercritical Pulverized Coal Combustion increases the thermal efficiency of a plant 35-45%, meaning that more coal can be burnt at a given temperature. Another method is Fluidized Bed Coal Combustion, in which coal can be burnt at relatively low temperatures.
Carbon Capture and Storage: To date, CCS is not commercially available and is highly expensive. Carbon Capture and Storage will involve three main steps: capturing carbon dioxide emissions from the flue gas within the smokestacks, compressing it from a gas into a liquid, and finally transporting that liquid through a pipeline to a repository underground where it will be stored for centuries. To date, there are methods of capturing CO2 (such as chemical absorption), but unfortunately the CCS process has two major problems. First, is that it requires a lot of energy; between removing the CO2 and collecting it for storage, twenty five percent more coal would have to be burnt to produce the same amount of electricity as before CCS was implemented. To produce this amount of coal, more energy would be required in mining and transportation—offsetting the environmental benefits of CCS. Second, coal fired power plants produce 1.5 billion tons of carbon dioxide per year. In order to capture this amount of CO2, 30 million barrels of the liquid would have to be filled every day. This number is higher than the number of barrels filled by petroleum products and it took approximately a hundred years to build the infrastructure the US currently uses to transport petroleum. Would it be possible for an even larger infrastructure to be built for CCS? Not to mention that this does not even include the problem of where the storage facility to be. It would be quite possible for the carbon dioxide to be pumped under the ground only to escape years later. And if it is pumped under the ocean, it is possible that the carbon dioxide would lower pH levels, affecting marine life. Thus to date, carbon capture and storage lacks the planning, infrastructure, and knowledge base to be a practical clean coal technology.
And if you didn’t feel like reading all that technical stuff, just read this:
I am attempting to condense a ten-page paper into a blog post, so not all my information can be put in here. However, there are some important points (and some personal opinions) that I would like to state. There are four main categories of clean coal technology, and many sound like promising technologies until one asks the question: where do the pollutants go? Like all magic tricks, to the viewer's eye the object may have ‘disappeared,’ but the magician knows that the rabbit has moved from inside the hat to under the table. Clean coal methods work by removing pollutants from the flue gas but they can't just "disappear," they have to be released somewhere else in the environment. When coal is burnt, these contaminants will inevitably be burnt as well, and they will have to go somewhere even if that isn’t directly into the atmosphere via flue gas.
Second, carbon capture and storage is far too expensive to be a viable option at the time being. It can increase the cost of a power plant anywhere from 20-90 percent—the lack of knowledge and experience is why that percentage is so uncertain. Third, I believe that technologies that improve the overall efficiency of the plants are the best technologies to be pursued. They result in less coal being excavated and less coal being burnt while achieving the same amount of electricity generation.
I believe funding can and should be spent on other investments besides coal. There are renewable energy sources and there are natural gas sources that produce half the amount of CO2 as coal. One type of renewable energy source I have come across recently is BioCoal. It is created from biomass and then treated to create a renewable coal. It meets all renewable fuel and CO2 reduction regulations, and is carbon neutral. BioCoal advocates state that it can be put into power plants today with no changes necessary. Do I believe this will actually ever happen? No. But it’s just a thought.
And lastly, energy conservation, energy conservation, energy conservation. Simply providing more incentives for the public to purchase LED lighting, energy efficient appliances, and better insulation for their housing would help significantly reduce the amount of coal needed to b burnt, and therefore the amount of CO2 emissions into the atmosphere. This can be done today and requires far less time, research, and money than CCS technologies. Coal certainly is not disappearing anytime soon, but it is important to remember that it is exhaustible, and we should be thinking ahead to the future.
Sources
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3. US Department of Energy, "Clean Coal Technology and The Clean Coal Power Initiative." http://www.fossil.energy.gov/programs/powersystems/cleancoal/
4. Green Peace Briefing, Climate, New Zealand, ""Clean Coal" Technology." http://www.greenpeace.org/raw/content/new-zealand/press/reports/clean-coal-technology-briefing.pdf
5. Garber, Kent. "Why Making Coal Cleaner Will Take Years." U.S. News & World Report, Apr, 2009, 66-68.
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7. James, Meigs B. "The Myth of Clean Coal: Analysis." July 14, 2011.http://www.popularmechanics.com/science/energy/coal-oil-gas/4339171
9. Berman, Ari. "The Dirt on Clean Coal." Nation 288, no. 14 (2009): 17-21.
10. Troy, Phaedra F. "Clean Coal Creates Emerging Job Market." Power Engineering 114, no. 12 (2010): 6-7.
11. Bradsher, Keith. "China Outpaces US in Cleaner Coal-Fired Plants. The New York Times". (May 10, 2009), http://www.nytimes.com/2009/05/11/world/asia/11coal.html.
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13. Fairley, Peter. "China's Coal Future. Technology Review". 110. 1 (2007), 56-61
14. Markham, Derek. "Can Bio Coal Turn Coal Power Plants into Green Energy Producers?." Dec 28, 2009. http://greenlivingideas.com/2009/12/28/bio-coal-turn-coal-power-plants-green-energy-producers/
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