IGCC Opens Way for
'Clean Coal' Power Plants
By Jeff Swicord
24 May 2007
Jeff Swicord traveled to Terre Haute, Indiana, to tour one of two so
called "clean coal" electric generating plants in the United States.
Clean coal technology has been under development since the early 1990s
in the U.S.. And in the next few years, 20 more plants will be built in
different parts of the country.
Toxic emission from
Coal is currently the
most abundant energy resource in the U.S. More than 600 coal-fired power
plants produce more than half of the country's electricity. But coal is
also one of the most environmentally unfriendly energy sources, and
emits pollution when it is mined, transported and burned.
For decades, coal-fired power plants across the country have emitted a
variety of dangerous toxic substances that harm the environment. They
include large amounts of carbon dioxide (CO2) that contribute to global
warming. But new "clean coal" technology is on the horizon that can
dramatically reduce the toxic emissions from coal-fired plants.
perspective, I think clean coal is part of the future," says Jared
Daniels, with the Office of Clean Coal Technology at the U.S. Department
of Energy.. "There is no silver bullet in energy technologies. If you
look at all the various forecasts, some time around 2050, electricity
demand in the U.S. is going to double."
The Wabash Valley Power plant in Terre Haute, Indiana, is one of two
Integrated Gasification Combined Cycle, or IGCC, plants in the U.S. IGCC
technology converts coal into synthetic gas by heating it at very high
temperature in this tall cylinder.
The pollutants, sulfur and carbon dioxide (CO2), are removed and sold as
products on the open market. Another byproduct, slag (a non-toxic solid
material left over from the gasification process) can be used in
building materials and asphalt for roads. There are two types of
turbines that generate electricity in the IGCC system: one that runs on
the natural gas, and another that runs on steam from the heat created
from the heat of the gasification process.
"The advantage is that because you gasify the coal, you can clean up the
contaminants as we discussed much more efficiently as they are more
concentrated," adds Daniels, "and on the power side, because you have a
gas turbine that is more efficient than a steam turbine in series with a
steam turbine, the overall efficiency of the process is increased."
Not everyone thinks coal should be considered as a viable future energy
source. "Calling coal clean is just propaganda to keep this dirty energy
source into the mix for the future" says Eric Pica, a representative of
the environmental group Friends of the Earth.
He acknowledges that the IGCC process produces far fewer pollutants than
traditional coal-fired plants, but he says pollution is only part of the
problem. "The problem is that these plants are getting their coal from
somewhere. They are getting their coal from the mountaintops of West
Virginia, which are being blown apart and scraped out like a pumpkin and
filling thousands of miles of streambeds. They are getting their coal
from the mining of strip mines out west."
Pica adds that the power industry plans to build 150 coal-powered plants
across the country in the next few years. Only 20 of them will be IGCC
plants. "The IGCC plants are being used to put a green spin on all these
coal plants that are going to be built, that are going to use pulverized
coal with all the traditional pollution from the coal."
IGCC plants are expensive to build. Jared Daniels acknowledges that
until stringent emission standards are placed on coal-fired plants,
there will be little economic incentive for power companies to build
He says IGCC technology is currently the best option for coal-generated
electricity. "We will need to rely on coal for the a long time going out
into the future. Perhaps some of the renewable technologies [will] come
of age and can gain a larger share of the market.
"I think when you realize that fact, you develop technology and
implement technology that uses coal in the most efficient and
environmentally sound manner possible," adds Daniels.