Measurements, abbreviations, and acronyms.

Measurements, abbreviations, and acronyms used in this subpart are defined as follows: Btu—British thermal unit CO 2 —carbon dioxide CSAPR—Cross-State Air Pollution Rule H 2 O—water hr—hour kWh—kilowatt-hour lb—pound mmBtu—million Btu MWe—megawatt electrical MWh—megawatt-hour NO X —nitrogen oxides O 2 —oxygen ppm—parts per million scfh—standard cubic feet per hour SIP—State implementation plan SO 2 —sulfur dioxide TR—Transport Rule yr—year [76 FR 48458, Aug. 8, 2011, as amended at 81 FR 74619, Oct. 26, 2016]