Docket No. EO-05-01: This report describes dispersion modeling performed for simultaneous operation of one baseload unit and two cycling units at Mirant’s Potomac River Generating Station (PRGS). This mode of operation is also referred to as Option A in Mirant Potomac River LLC’s December 30, 2005 letter to the U.S. Department of Energy regarding District of Columbia Public Service Commission, Docket No. EO-05- 01. The modeling was performed according to the Protocol approved by the Virginia Department of Environmental Quality. The purpose of the modeling was to demonstrate that Option A operations will not cause or contribute to exceedances of the National Ambient Air Quality Standards (NAAQS).