In this subtitle the following words have the meanings indicated. “Affected facility” means an electricity generating unit in the State that includes a coal fired boiler or indirect heat exchanger that was exempted from the Prevention of Significant Deterioration review under Title 1 of the 1977 federal Clean Air Act. “Affected facility” includes: Wagner, units 2 and 3; Subject to § 2-1003(c) of this subtitle, R.P. Smith, units 3 and 4; Morgantown Generating Station, units 1 and 2; Dickerson, units 1, 2, and 3; Crane, units 1 and 2; Chalk Point Generating Station, units 1 and 2; and Brandon Shores, units 1 and 2. “Affected facility” does not include any electricity generating unit: That operates in combination with equipment used to recover useful thermal energy for industrial, commercial, heating, or cooling purposes through sequential use of energy; or That supplies in any calendar year less than one-half of the electricity generated by such unit to any utility power distribution system for sale. “Allowance” means: One ton of sulfur dioxide that may be bought, sold, traded, or banked for use under the Acid Rain Program in the U.S. Environmental Protection Agency; or One ton of oxides of nitrogen that may be bought, sold, traded, or banked for use under the Nitrogen Oxides Budget Trading Program in the U.S. Environmental Protection Agency. “PJM Region” has the meaning stated under § 7–701 of the Public Utilities Article.