---
kind: "section"
citation: "40 C.F.R. § 98.263"
title: "40"
number: "98.263"
heading: "Calculating GHG emissions."
url: "https://uscodex.org/cfr/40/98.263"
---

# §98.263. Calculating GHG emissions.


You must calculate and report the annual process CO2 emissions from each wet-process phosphoric acid process line using the procedures in either paragraph [(a)](#a) or [(b)](#b) of this section.

- (a) Calculate and report under this subpart the process CO2 emissions by operating and maintaining a CEMS according to the Tier 4 Calculation Methodology specified in [§ 98.33(a)(4)](/cfr/40/98.33.md?p=a-4) and all associated requirements for Tier 4 in [subpart C](/cfr/40/subpartC.md) of this part (General Stationary Fuel Combustion Sources).
- (b) Calculate and report under this subpart the process CO2 emissions using the procedures in paragraphs [(b)(1)](#b-1) and [(b)(2)](#b-2) of this section.
  - (1) Calculate the annual CO2 mass emissions from each wet-process phosphoric acid process line using the methods in paragraphs [(b)(1)(i)](#b-1-i) or [(ii)](#b-1-ii) of this section, as applicable.
    - (i) If your process measurement provides the inorganic carbon content of phosphate rock as an output, calculate and report the process CO2 emissions from each wet-process phosphoric acid process line using Equation Z-1a of this section:
    - (ii) If your process measurement provides the CO2 content directly as an output, calculate and report the process CO2 emissions from each wet-process phosphoric acid process line using Equation Z-1b of this section:
  - (2) You must determine the total emissions from the facility using Equation Z-2 of this section:
- (c) If GHG emissions from a wet-process phosphoric acid process line are vented through the same stack as any combustion unit or process equipment that reports CO2 emissions using a CEMS that complies with the Tier 4 Calculation Methodology in [subpart C](/cfr/40/subpartC.md) of this part (General Stationary Fuel Combustion Sources), then the calculation methodology in [paragraph (b)](#b) of this section shall not be used to calculate process emissions. The owner or operator shall report under this subpart the combined stack emissions according to the Tier 4 Calculation Methodology in [§ 98.33(a)(4)](/cfr/40/98.33.md?p=a-4) and all associated requirements for Tier 4 in [subpart C](/cfr/40/subpartC.md) of this part.

## Notes

### Amendments

[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 66468, Oct. 28, 2010; 78 FR 71964, Nov. 29, 2013]

### Authority

Authority: 42 U.S.C. 7401-7671q.

### Source

Source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.

### Amendments

[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 66468, Oct. 28, 2010; 78 FR 71964, Nov. 29, 2013]