Exelon to pay $3.5M for more study of Conowingo Dam Exelon Corp. will pay up to $3.5 million to fund more study of the Conowingo power dam. Check out this story on delmarvanow.com: http://www.delmarvanow.com/story/news/2014/12/08/conowingo-dam-chesapeake-susquehanna/20101377/ The Maryland Department of the Environment says Exelon Corp. will pay up to $3.5 million to fund more study of the Conowingo power dam's effects on Susquehanna River and Chesapeake Bay water quality.