Regulators canceled, suspended or refused several plans to develop clean coal-fired plants citing construction costs, technological pitfalls and regulation regarding greenhouse gas emissions, USA Today said Thursday.

Clean coal-fired plants cost 20 percent more to build than standard plants but long-term expenses are 20 percent less than standard plants, Ed Rubin, an environmental engineering scientist with Carnegie Mellon University, told USA Today.

Only two clean coal-fired plants operate in the United States but that number may increase because the newer plants are more readily retrofitted to reduce carbon dioxide emissions, the newspaper said.

The Ohio-based electric utility American Electric Power (NYSE:AEP) is proposing two new clean coal-fired plants in Ohio and West Virginia.

"I think it's essential that we as a nation take advantage of one of the indigenous fuel sources we have," said Michael Morris with AEP.