Luminant is the 13th company to join the FutureGen Alliance, which is set to announce the final site selection for the plant later this month.

"Luminant's addition to the world-class utility and coal companies across the globe who are alliance members continues to build momentum and support for the FutureGen program," said group chief executive Michael Mudd.

"We welcome the opportunity to work with Luminant as we advance technologies to reduce carbon emissions while continuing to use coal."

Luminant CEO Mike Greene agreed, noting its membership commits the company to looking at "new, innovative, emerging technologies" for more efficient and cleaner energy.

"The FutureGen project represents the next step in environmentally friendly coal-fuelled [power] generation, and will ultimately result in cleaner electricity production," he said.

The four finalist sites vying to call the FutureGen project home are Odessa and Jewett in Texas and Mattoon and Tuscola in Illinois.

Other members of the FutureGen Alliance include American Electric Power, Anglo American, BHP Billiton, the China Huaneng Group, Consol Energy, E.ON US, Foundation Coal, Rio Tinto Energy America, Peabody Energy, PPL Corporation, Southern Company and Xstrata Coal.

FutureGen will produce 275 megawatts of electric power, or enough electricity to power 150,000 homes, as well as hydrogen for fuel-cell technology.