---
kind: "section"
citation: "40 C.F.R. § 98.523"
title: "40"
number: "98.523"
heading: "Calculating GHG emissions."
url: "https://uscodex.org/cfr/40/98.523"
---

# §98.523. Calculating GHG emissions.


You must calculate and report the annual process CO2 emissions from each ceramics process unit using the procedures in [paragraphs (a) through (c)](#a..c) of this section.

- (a) For each ceramics process unit that meets the conditions specified in § [98.33(b)(4)(ii)](/cfr/40/98.33.md?p=b-4-ii) or [(iii)](/cfr/40/98.33.md?p=b-4-iii), you must calculate and report under this subpart the combined process and combustion CO2 emissions by operating and maintaining a CEMS to measure CO2 emissions 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.
- (b) For each ceramics process unit that is not subject to the requirements in [paragraph (a)](#a) of this section, calculate and report the process and combustion CO2 emissions from the ceramics process unit separately by using the procedures specified in [paragraphs (b)(1) through (6)](#b-1..b-6) of this section, except as specified in [paragraph (c)](#c) of this section.
  - (1) For each carbonate-based raw material (including clay) charged to the ceramics process unit, either obtain the mass fractions of any carbonate-based minerals from the supplier of the raw material or by sampling the raw material, or use a default value of 1.0 as the mass fraction for the raw material.
  - (2) **Determine the quantity of each carbonate-based raw material charged to the ceramics process unit.**
  - (3) Apply the appropriate emission factor for each carbonate-based raw material charged to the ceramics process unit. Table 1 to this subpart provides emission factors based on stoichiometric ratios for carbonate-based minerals.
  - (4) Use equation 1 to this [paragraph (b)(4)](#b-4) to calculate process mass emissions of CO2 for each ceramics process unit:
  - (5) Determine the combined annual process CO2 emissions from the ceramic process units at your facility using equation 2 to this [paragraph (b)(5)](#b-5):
  - (6) Calculate and report under [subpart C](/cfr/40/subpartC.md) of this part the combustion CO2 emissions in the ceramics process unit according to the applicable requirements in [subpart C](/cfr/40/subpartC.md) of this part.
- (c) A value of 1.0 can be used for the mass fraction (MFi) of carbonate-based mineral i in each carbonate-based raw material j in equation 1 to [paragraph (b)(4)](#b-4) of this section. The use of 1.0 for the mass fraction assumes that the carbonate-based raw material comprises 100% of one carbonate-based mineral. As an alternative to the default value, you may use data provided by either the raw material supplier or a lab analysis.

## Notes

### Source

Source: 89 FR 31948, Apr. 25, 2024, unless otherwise noted.

### Authority

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

### Source

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