Construction of Killen Station began in 1974 and commenced commercial generation in 1982 at a cost of $588 million. The plant was named after Robert B. Killen, a former chairman of
Dayton Power & Light (DP&L). A second coal unit was planned, but was cancelled in 1980 after estimates for electric use in the next decade were revised showing demand stagnating. Killen's coal unit was retrofitted with a
selective catalytic reduction (SCR) system between 2003 and 2004 by
Black & Veatch. The SCR was installed to comply with the
Clean Air Act's 1990 amendments and Ohio's State Implementation Plan (SIP).
Flue-gas desulfurization (FGD) equipment, designed by the
Chiyoda Corporation, was installed at Killen in 2007 to reduce
sulfur dioxide () emissions. In August 2014, Duke Energy sold its stake in the coal unit to
Dynegy. Operations at Killen were transferred from DP&L to AES Ohio Generation in October 2017.
Closure DP&L announced plans in March 2017 to close Killen Station along with its sister plant
J.M. Stuart Station due to economic and environmental challenges in an agreement with the
Sierra Club and several unnamed parties. The commercial generation of Killen ceased on May 31, 2018. In December 2019, DP&L sold the site to Kingfisher Development for remediation and redevelopment. ==Incidents==