United States, June 17 -- Duke Energy Indiana and Reliable Energy Inc., which represents several of Indiana's major coal producers, have reached a settlement in Duke Energy Indiana's request pending before the Indiana Utility Regulatory Commission for a proposed new natural gas plant at its Cayuga Generating Station in Vermillion County, Ind.If state utility regulators approve the gas plant proposal as well as the settlement, Duke Energy Indiana has agreed to perform an engineering study to evaluate the technical feasibility of continued operation of the site's current coal units by third parties that may be interested in purchasing them. Duke Energy would then issue a request for proposal to solicit interest in the coal units, which could ...