An Environment of Change: Part 7
Clean Coal: Giving Coal a ‘Makeover’
Note to readers: The seventh part of our ongoing series
continues breaking down each element of the EPRI “prism” strategy.
This one is on clean coal technology.
Gasification technology will keep coal a vital resources
Coal provides half of the electricity used in the United States. In Indiana, almost 95 percent of our electricity comes from burning coal.
No serious discussion about meeting the growing demand for electricity can begin without including coal.
But coal also releases more carbon dioxide (CO2) when it’s burned than any other fossil fuel. How to keep coal a vital energy source while mitigating its effects on the environment will be a challenge in the coming decades.
Researchers, electric utilities and consumers are pinning their hopes on emerging technologies that will allow more efficient and clean use of coal. Clean coal is another facet of the 2007 “prism” study by the Electric Power Research Institute that shows how the nation can cut carbon dioxide emissions to 1990 levels by 2030 and still keep the lights on through aggressive steps in seven areas. One cutting-edge technology is already being used right here in Indiana, producing electricity for 150,000 co-op consumers.
The sgSolutions Intigrated Gasification Combined Cycle (IGCC) plant, co-owned by Wabash Valley Power Association, transforms coal or petroleum coke into high-value, clean synthetic gas. The synthetic gas is then used the same way as natural gas to generate electricity. Wabash Valley Power is the Indianapolis-based cooperative power supplier for the REMCs in the northern half of Indiana and several co-ops in Ohio, Michigan, Illinois and Missouri.
The plant works by taking coal or — primarily right now — petroleum coke (a coal-like by-product from oil refineries) and combining it with water to form a flowable solid mixture called a slurry. This mixture is then pumped into a heated tank along with oxygen where it undergoes physical and chemical reactions to produce a gaseous fuel called syngas.
Various impurities are then removed from the syngas prior to using it as a fuel source, making the resulting emissions far cleaner than those of a conventional coal plant. This includes removing roughly 50 percent of the mercury in coal and over 97 percent of the sulfur, thereby significantly reducing sulfur dioxide (SO2) emissions.
In addition, due to the higher efficiency of this technology, CO2 emissions are 20 percent lower than typical coal plants currently in operation.
The gasification process also lends itself more easily to the emerging carbon capture and storage technology (discussed in Part 6 of this series) which could eliminate carbon dioxide emissions into the atmosphere.
The gasification process also creates useful byproducts used in the construction and agriculture industries.
The clean synthetic gas created at the plant is then piped to the adjacent WVPA owned, Wabash River Combined Cycle Plant to generate 292 megawatts of clean coal power.
The sgSolutions was built in the mid-1990s with help from the U.S. Department of Energy, in the form of a grant given to a joint venture fromed by PSI/Cinergy and Destec Energy, a partially held subsidiary of DOW Chemical.
This particular gasification technology is now owned by ConocoPhillips. ConocoPhillips remains a partner in the facility, as owners of the technology and managers of the plant.
Wabash Valley Power became a co-owner of the gasification plant in 2005 and has been the sole owner of the associated Wabash River Combined Cycle power generation facility since early 2008.
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Written By: eceditor
Date Posted: 8/29/2008
Number of Views: 1427
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