# 98.83 Calculating GHG emissions.
You must calculate and report the annual process CO<sub>2</sub> emissions from each kiln using the procedure in paragraphs (a) and (b) of this section.
(a) For each cement kiln that meets the conditions specified in § 98.33(b)(4)(ii) or (b)(4)(iii), you must calculate and report under this subpart the combined process and combustion CO<sub>2</sub> emissions by operating and maintaining a CEMS to measure CO<sub>2</sub> emissions according to the Tier 4 Calculation Methodology specified in § 98.33(a)(4) and all associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).
(b) For each kiln that is not subject to the requirements in paragraph (a) of this section, calculate and report the process and combustion CO<sub>2</sub> emissions from the kiln by using the procedure in either paragraph (c) or (d) of this section.
(c) Calculate and report under this subpart the combined process and combustion CO<sub>2</sub> emissions by operating and maintaining a CEMS to measure CO<sub>2</sub> emissions according to the Tier 4 Calculation Methodology specified in § 98.33(a)(4) and all associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).
(d) Calculate and report process and combustion CO<sub>2</sub> emissions separately using the procedures specified in paragraphs (d)(1) through (d)(4) of this section.
(1) Calculate CO<sub>2</sub> process emissions from all kilns at the facility using equation H-1 to this section:
Where:
CO<sub>2 CMF</sub> = Annual process emissions of CO<sub>2</sub> from cement manufacturing, metric tons.
CO<sub>2 Cli,m</sub> = Total annual emissions of CO<sub>2</sub> from clinker production from kiln m, metric tons.
CO<sub>2 rm,m</sub> = Total annual emissions of CO<sub>2</sub> from raw materials from kiln m, metric tons.
k = Total number of kilns at a cement manufacturing facility.
(2) *CO*<sub>2</sub> *emissions from clinker production.* Calculate CO<sub>2</sub> emissions from each kiln using Equations H-2 through H-5 of this section.
Where:
Cli,<sub>j</sub> = Quantity of clinker produced in month j from kiln m, tons.
EF<sub>Cli,j</sub> = Kiln specific clinker emission factor for month j for kiln m, metric tons CO<sub>2</sub>/metric ton clinker computed as specified in Equation H-3 of this section.
CKD,<sub>i</sub> = Cement kiln dust (CKD) not recycled to the kiln in quarter i from kiln m, tons.
EF<sub>CKD,i</sub> = Kiln specific CKD emission factor for quarter i from kiln m, metric tons CO<sub>2</sub>/metric ton CKD computed as specified in Equation H-4 of this section.
p = Number of months for clinker calculation, 12.
r = Number of quarters for CKD calculation, 4.
2000/2205 = Conversion factor to convert tons to metric tons.
(i) *Kiln-Specific Clinker Emission Factor.* (A) Calculate the kiln-specific clinker emission factor using Equation H-3 of this section.
Where:
Cli<sub>CaO</sub> = Monthly total CaO content of Clinker, wt-fraction.
Cli<sub>ncCaO</sub> = Monthly non-calcined CaO content of Clinker, wt-fraction.
MR<sub>CaO</sub> = Molecular-weight Ratio of CO<sub>2</sub>/CaO = 0.785.
Cli<sub>MgO</sub> = Monthly total MgO content of Clinker, wt-fraction.
Cli<sub>ncMgO</sub> = Monthly non-calcined MgO content of Clinker, wt-fraction.
MR<sub>MgO</sub> = Molecular-weight Ratio of CO<sub>2</sub>/MgO = 1.092.
(B) Non-calcined CaO is CaO that remains in the clinker in the form of CaCO<sub>3</sub> and CaO in the clinker that entered the kiln as a non-carbonate species. Non-calcined MgO is MgO that remains in the clinker in the form of MgCO<sub>3</sub> and MgO in the clinker that entered the kiln as a non-carbonate species.
(ii) *Kiln-Specific CKD Emission Factor.* (A) Calculate the kiln-specific CKD emission factor for CKD not recycled to the kiln using Equation H-4 of this section.
Where:
CKD<sub>CaO</sub> = Quarterly total CaO content of CKD not recycled to the kiln, wt-fraction.
CKD<sub>ncCaO</sub> = Quarterly non-calcined CaO content of CKD not recycled to the kiln, wt-fraction.
MR<sub>CaO</sub> = Molecular-weight Ratio of CO<sub>2</sub>/CaO = 0.785.
CKD<sub>MgO</sub> = Quarterly total MgO content of CKD not recycled to the kiln, wt-fraction.
CKD<sub>ncMgO</sub> = Quarterly non-calcined MgO content of CKD not recycled to the kiln, wt-fraction.
MR<sub>MgO</sub> = Molecular-weight Ratio of CO<sub>2</sub>/MgO = 1.092.
(B) Non-calcined CaO is CaO that remains in the CKD in the form of CaCO<sub>3</sub> and CaO in the CKD that entered the kiln as a non-carbonate species. Non-calcined MgO is MgO that remains in the CKD in the form of MgCO<sub>3</sub> and MgO in the CKD that entered the kiln as a non-carbonate species.
(3) *CO*<sub>2</sub>* emissions from raw materials from each kiln.* Calculate CO<sub>2</sub> emissions from raw materials using equation H-5 to this section:
Where:
rm = The amount of raw material i consumed annually from kiln m, tons/yr (dry basis) or the amount of raw kiln feed consumed annually from kiln m, tons/yr (dry basis).
CO<sub>2,rm,m</sub> = Annual CO<sub>2</sub> emissions from raw materials from kiln m.
TOC<sub>rm</sub> = Organic carbon content of raw material i from kiln m or organic carbon content of combined raw kiln feed (dry basis) from kiln m, as determined in § 98.84(c) or using a default factor of 0.2 percent of total raw material weight.
M = Number of raw materials or 1 if calculating emissions based on combined raw kiln feed.
44/12 = Ratio of molecular weights, CO<sub>2</sub> to carbon.
2000/2205 = Conversion factor to convert tons to metric tons.
(4) Calculate and report under subpart C of this part (General Stationary Fuel Combustion Sources) the combustion CO<sub>2</sub> emissions from the kiln according to the applicable requirements in subpart C.
[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 66461, Oct. 28, 2010; 89 FR 31905, Apr. 25, 2024]