(a) The owner or operator of a unit with a CO2 continuous emission monitoring system for determining CO2 mass emissions in accordance with § 75.10 (or an O2 monitor that is used to determine CO2 concentration in accordance with appendix F to this part) shall substitute for missing CO2 pollutant concentration data using the procedures of paragraphs (b) and (d) of this section.

(b) During the first 720 quality-assured monitor operating hours following initial certification at a particular unit or stack location (i.e., the date and time at which quality-assured data begins to be recorded by a CEMS at that location), or (when implementing these procedures for a previously certified CO2 monitoring system) during the 720 quality-assured monitor operating hours preceding implementation of the standard missing data procedures in paragraph (d) of this section, the owner or operator shall provide substitute CO2 pollutant concentration data or substitute CO2 data for heat input determination, as applicable, according to the procedures in § 75.31(b).

(c) [Reserved]

(d) Upon completion of 720 quality-assured monitor operating hours using the initial missing data procedures of § 75.31(b), the owner or operator shall provide substitute data for CO2 concentration or substitute CO2 data for heat input determination, as applicable, in accordance with the procedures in § 75.33(b) except that the term “CO2 concentration” shall apply rather than “SO2 concentration,” the term “CO2 pollutant concentration monitor” or “CO2 diluent monitor” shall apply rather than “SO2 pollutant concentration monitor,” and the term “maximum potential CO2 concentration, as defined in section 2.1.3.1 of appendix A to this part” shall apply, rather than “maximum potential SO2 concentration.”