The announcement was made at a conference discussing ways to capture and store greenhouse gases, including carbon dioxide.

Secretary of Energy Samuel Bodman said a key feature of the FutureGen plant would be trapping and permanently storing carbon gases deep underground, along with other cutting-edge techniques that could virtually eliminate air emissions from the plant.

Bodman said the 12 candidate sites had been received by the FutureGen Alliance, a group of coal companies and electric utilities that were partnering with the US Department of Energy to design and build the plant.

Alliance chief executive Mike Mudd said the sites were submitted in response to a public request for proposals, and are located across Illinois, Kentucky, North Dakota, Ohio, Texas, West Virginia and Wyoming.

He said the FutureGen plant would be the first-ever integration of highly advanced technologies that either capture or prevent the formation of pollutants and other waste products that have previously created environmental concerns about the use of coal.

Mudd said air pollutants would be reduced almost to zero, solid wastes would be converted to useful commercial products, and as much as 90% of the total carbon dioxide produced by the plant was expected to be captured initially.

“FutureGen will be a stepping stone toward a cleaner, more energy-secure future. One of these sites ultimately will become known worldwide as the place where a new generation of zero-emission energy plants made its debut,” he said.

The alliance's selection of a final site is scheduled for the third quarter of 2007. Plant start-up is planned for 2012.