In this chapter, the following terms have the meanings indicated. Terms Defined. “Affected electric generating unit” means any one of the following coal-fired electric generating units: Brandon Shores Units 1 and 2; C.P. Crane Units 1 and 2; Chalk Point Units 1 and 2; Dickerson Units 1, 2, and 3; H.A. Wagner Units 2 and 3; Morgantown Units 1 and 2; and Warrior Run. “Emergency operations” means an event called when PJM Interconnection, LLC or a successor independent system operator, acts to invoke one or more of the Warning or Action procedures in accordance with PJM Manual 13, Revision 57, as amended, to avoid potential interruption in electric service and maintain electric system reliability. “Operating day” means a 24-hour period beginning midnight of one day and ending the following midnight, or an alternative 24-hour period approved by the Department, during which time an installation is operating, consuming fuel, or causing emissions. “Ozone season” means the period beginning May 1 of any given year and ending September 30 of the same year. System. “System” means all affected electric generating units within the State of Maryland subject to this chapter that are owned, operated, or controlled by the same person and are located: In the same ozone nonattainment area as specified in 40 CFR Part 81; or Outside any designated ozone nonattainment area as specified in 40 CFR Part 81. “System” includes at least two affected electric generating units. “System operating day” means any day in which an electric generating unit in a system operates. “30-day rolling average emission rate” means a value in lbs/MMBtu calculated by: Summing the total pounds of pollutant emitted from the unit during the current operating day and the previous 29 operating days; Summing the total heat input to the unit in MMBtu during the current operating day and the previous 29 operating days; and Dividing the total number of pounds of pollutant emitted during the 30 operating days by the total heat input during the 30 operating days. “30-day systemwide rolling average emission rate” means a value in lbs/MMBtu calculated by: Summing the total pounds of pollutant emitted from the system during the current system operating day and the previous 29 system operating days; Summing the total heat input to the system in MMBtu during the current system operating day and the previous 29 system operating days; and Dividing the total number of pounds of pollutant emitted during the 30 system operating days by the total heat input during the 30 system operating days. “24-hour block average emission rate” means a value in lbs/MMBtu calculated by: Summing the total pounds of pollutant emitted from the unit during 24 hours between midnight of one day and ending the following midnight; Summing the total heat input to the unit in MMBtu during 24 hours between midnight of one day and ending the following midnight; and Dividing the total number of pounds of pollutant emitted during 24 hours between midnight of one day and ending the following midnight by the total heat input during 24 hours between midnight of one day and ending the following midnight. “24-hour systemwide block average emission rate” means a value in lbs/MMBtu calculated by: Summing the total pounds of pollutant emitted from the system during 24 hours between midnight of one day and ending the following midnight; Summing the total heat input to the system in MMBtu during 24 hours between midnight of one day and ending the following midnight; and Dividing the total number of pounds of pollutant emitted during 24 system hours between midnight of one day and ending the following midnight by the total heat input during 24 system hours between midnight of one day and ending the following midnight.