§ 98.163 - Calculating GHG emissions.

§ 98.163 Calculating GHG emissions.

Cross Reference

Link to an amendment published at 89 FR 31926, Apr. 25, 2024.

You must calculate and report the annual CO₂ emissions from each hydrogen production process unit using the procedures specified in either paragraph (a) or (b) of this section.

(a) Continuous Emissions Monitoring Systems (CEMS). Calculate and report under this subpart the CO₂ emissions by operating and maintaining CEMS 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) Fuel and feedstock material balance approach. Calculate and report CO₂ emissions as the sum of the annual emissions associated with each fuel and feedstock used for hydrogen production by following paragraphs (b)(1) through (3) of this section. The carbon content and molecular weight shall be obtained from the analyses conducted in accordance with § 98.164(b)(2), (b)(3), or (b)(4), as applicable, or from the missing data procedures in § 98.165. If the analyses are performed annually, then the annual value shall be used as the monthly average. If the analyses are performed more frequently than monthly, use the arithmetic average of values obtained during the month as the monthly average.

(1) Gaseous fuel and feedstock. You must calculate the annual CO₂ emissions from each gaseous fuel and feedstock according to Equation P-1 of this section:

Where:

CO₂ = Annual CO₂ process emissions arising from fuel and feedstock consumption (metric tons/yr).

Fdstk_n = Volume or mass of the gaseous fuel or feedstock used in month n (scf (at standard conditions of 68 °F and atmospheric pressure) or kg of fuel or feedstock).

CC_n = Average carbon content of the gaseous fuel or feedstock for month n (kg carbon per kg of fuel or feedstock).

MW_n = Average molecular weight of the gaseous fuel or feedstock for month n (kg/kg-mole). If you measure mass, the term “MW_n/MVC” is replaced with “1”.

MVC = Molar volume conversion factor (849.5 scf per kg-mole at standard conditions).

k = Months in the year.

44/12 = Ratio of molecular weights, CO₂ to carbon. 0.001 = Conversion factor from kg to metric tons.

(2) Liquid fuel and feedstock. You must calculate the annual CO₂ emissions from each liquid fuel and feedstock according to Equation P-2 of this section:

Where:

CO₂ = Annual CO₂ emissions arising from fuel and feedstock consumption (metric tons/yr).

Fdstk_n = Volume or mass of the liquid fuel or feedstock used in month n (gallons or kg of fuel or feedstock).

CC_n = Average carbon content of the liquid fuel or feedstock, for month n (kg carbon per gallon or kg of fuel or feedstock).

k = Months in the year.

44/12 = Ratio of molecular weights, CO₂ to carbon.

0.001 = Conversion factor from kg to metric tons.

(3) Solid fuel and feedstock. You must calculate the annual CO₂ emissions from each solid fuel and feedstock according to Equation P-3 of this section:

Where:

CO₂ = Annual CO₂ emissions from fuel and feedstock consumption (metric tons/yr).

Fdstk_n = Mass of solid fuel or feedstock used in month n (kg of fuel or feedstock).

CC_n = Average carbon content of the solid fuel or feedstock, for month n (kg carbon per kg of fuel or feedstock).

k = Months in the year.

44/12 = Ratio of molecular weights, CO₂ to carbon.

0.001 = Conversion factor from kg to metric tons.

(c) If GHG emissions from a hydrogen production process unit 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 of this part (General Stationary Fuel Combustion Sources), then the calculation methodology in paragraph (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) and all associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).

[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 66463, Oct. 28, 2010; 75 FR 79157, Dec. 17, 2010; 78 FR 71955, Nov. 29, 2013; 81 FR 89257, Dec. 9, 2016]