AEP puts nation’s first ultra-supercritical coal plant online - Clarksburg, Morgantown: News, Sports, Weather

AEP puts nation’s first ultra-supercritical coal plant online

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Coal-fired power moved into the future Dec. 20 when the first ultra-supercritical power generating unit in the U.S. went online.

The 600-megawatt John W. Turk, Jr. power plant in Arkansas, operated by AEP subsidiary Southwestern Electric Power Co., uses the most efficient pulverized coal technology. Only "integrated gasification and combined cycle" technology is more efficient.

The term "ultra-supercritical" refers to the temperature and pressure of the steam.

In conventional sub-critical generation, water is converted to steam through the process of boiling, AEP explains on its website.

"At supercritical pressures, water is heated to produce steam through a gradual expansion without boiling," the website reads. "Due to improved thermodynamics … a supercritical steam generating unit is more efficient than a sub-critical unit."

Now, advances in metals have made even higher-temperature and -pressure "ultra-supercritical" operation possible.

What difference does it make?

Here's how much of the energy in coal is converted to electricity for the three technologies: 34.3 percent for subcritical, 38.5 percent for supercritical and 43.3 percent for ultra-supercritical, according to representative calculations in MIT's 2007 "Future of Coal" study.

AEP references 39 to 40 percent for its ultra-supercritical technology.

In either case, it means less coal used and fewer emissions generated for the same amount of electricity.

The new facility is named for John W. Turk Jr., who was president and chief executive officer of SWEPCO from 1983 to 1988, AEP said in a media release. A Texas native and graduate of the University of Texas, Turk worked for SWEPCO for 39 years. He passed away in 2009.