Measurements, abbreviations, and acronyms used in this subpart and subparts BBB through III are defined as follows:

Btu—British thermal unit CO2—carbon dioxide H2O—water Hg—mercuryhr—hour kW—kilowatt electricalkWh—kilowatt hourlb—poundmmBtu—million Btu MWe—megawatt electrical MWh—megawatt hour NOX—nitrogen oxides O2—oxygenppm—parts per millionscfh—standard cubic feet per hour SO2—sulfur dioxideyr—year[71 FR 25387, Apr. 28, 2006]