Measurements, abbreviations, and acronyms used in this subpart are defined as follows: Btu--British thermal unitCO2--carbon dioxideH2O--waterhr--hourkW--kilowatt electricalkWh--kilowatt hourlb--poundmmBtu--million BtuMWe--megawatt electricalMWh--megawatt hourNOX--nitrogen oxidesO2--oxygenppm--parts per millionscfh--standard cubic feet per hourSO2--sulfur dioxideyr--year