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Subpart P—Hydrogen Production

§98.160 Definition of the source category.

(a) A hydrogen production source category consists of facilities that produce hydrogen 

gas sold as a product to other entities.

(b) This source category comprises process units that produce hydrogen by reforming, 

gasification, oxidation, reaction, or other transformations of feedstocks.

(c) This source category includes merchant hydrogen production facilities located within 

another facility if they are not owned by, or under the direct control of, the other facility's owner 

and operator.

§98.161 Reporting threshold.

You must report GHG emissions under this subpart if your facility contains a hydrogen 

production process and the facility meets the requirements of either §98.2(a)(1) or (a)(2).

§98.162 GHGs to report.

You must report:

(a) CO2 emissions from each hydrogen production process unit.

(b) [Reserved]

(c) CO2, CH4, and N2O emissions from each stationary combustion unit other than 

hydrogen production process units. You must calculate and report these emissions under subpart 

C of this part (General Stationary Fuel Combustion Sources) by following the requirements of 

subpart C.

(d) For CO2 collected and transferred off site, you must follow the requirements of 

subpart PP of this part.

§98.163 Calculating GHG emissions.
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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).

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

per kg of fuel or feedstock).

MWn = Average molecular weight of the gaseous fuel or feedstock for month n (kg/kgmole). If you measure mass, the term “MWn/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).

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

fuel or feedstock).

CCn = 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:
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Where:

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

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

CCn = 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).

§98.164 Monitoring and QA/QC requirements.

The GHG emissions data for hydrogen production process units must be quality-assured 

as specified in paragraphs (a) or (b) of this section, as appropriate for each process unit:

(a) If a CEMS is used to measure GHG emissions, then the facility must comply with the 

monitoring and QA/QC procedures specified in §98.34(c).

(b) If a CEMS is not used to measure GHG emissions, then you must:
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(1) Calibrate all oil and gas flow meters that are used to measure liquid and gaseous fuel 

and feedstock volumes (except for gas billing meters) according to the monitoring and QA/QC 

requirements for the Tier 3 methodology in §98.34(b)(1). Perform oil tank drop measurements (if 

used to quantify liquid fuel or feedstock consumption) according to §98.34(b)(2). Calibrate all 

solids weighing equipment according to the procedures in §98.3(i).

(2) Determine the carbon content and the molecular weight annually of standard gaseous 

hydrocarbon fuels and feedstocks having consistent composition (e.g., natural gas). For other 

gaseous fuels and feedstocks (e.g., biogas, refinery gas, or process gas), sample and analyze no 

less frequently than weekly to determine the carbon content and molecular weight of the fuel and 

feedstock.

(3) Determine the carbon content of fuel oil, naphtha, and other liquid fuels and 

feedstocks at least monthly, except annually for standard liquid hydrocarbon fuels and feedstocks 

having consistent composition, or upon delivery for liquid fuels and feedstocks delivered by bulk 

transport (e.g., by truck or rail).

(4) Determine the carbon content of coal, coke, and other solid fuels and feedstocks at 

least monthly, except annually for standard solid hydrocarbon fuels and feedstocks having 

consistent composition, or upon delivery for solid fuels and feedstocks delivered by bulk 

transport (e.g., by truck or rail).

(5) You must use the following applicable methods to determine the carbon content for 

all fuels and feedstocks, and molecular weight of gaseous fuels and feedstocks. Alternatively, 

you may use the results of chromatographic analysis of the fuel and feedstock, provided that the 

chromatograph is operated, maintained, and calibrated according to the manufacturer's 
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instructions; and the methods used for operation, maintenance, and calibration of the 

chromatograph are documented in the written monitoring plan for the unit under §98.3(g)(5).

(i) ASTM D1945-03 Standard Test Method for Analysis of Natural Gas by Gas 

Chromatography (incorporated by reference, see §98.7).

(ii) ASTM D1946-90 (Reapproved 2006), Standard Practice for Analysis of Reformed 

Gas by Gas Chromatography (incorporated by reference, see §98.7).

(iii) ASTM D2013-07 Standard Practice of Preparing Coal Samples for Analysis 

(incorporated by reference, see §98.7).

(iv) ASTM D2234/D2234M-07 Standard Practice for Collection of a Gross Sample of 

Coal (incorporated by reference, see §98.7).

(v) ASTM D2597-94 (Reapproved 2004) Standard Test Method for Analysis of 

Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas 

Chromatography (incorporated by reference, see §98.7).

(vi) ASTM D3176-89 (Reapproved 2002), Standard Practice for Ultimate Analysis of 

Coal and Coke (incorporated by reference, see §98.7).

(vii) ASTM D3238-95 (Reapproved 2005), Standard Test Method for Calculation of 

Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method 

(incorporated by reference, see §98.7).

(viii) ASTM D4057-06 Standard Practice for Manual Sampling of Petroleum and 

Petroleum Products (incorporated by reference, see §98.7).

(ix) ASTM D4177-95 (Reapproved 2005) Standard Practice for Automatic Sampling of 

Petroleum and Petroleum Products (incorporated by reference, see §98.7).
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(x) ASTM D5291-02 (Reapproved 2007), Standard Test Methods for Instrumental 

Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants 

(incorporated by reference, see §98.7).

(xi) ASTM D5373-08 Standard Test Methods for Instrumental Determination of Carbon, 

Hydrogen, and Nitrogen in Laboratory Samples of Coal (incorporated by reference, see §98.7).

(xii) ASTM D6609-08 Standard Guide for Part-Stream Sampling of Coal (incorporated 

by reference, see §98.7).

(xiii) ASTM D6883-04 Standard Practice for Manual Sampling of Stationary Coal from 

Railroad Cars, Barges, Trucks, or Stockpiles (incorporated by reference, see §98.7).

(xiv) ASTM D7430-08ae1 Standard Practice for Mechanical Sampling of Coal 

(incorporated by reference, see §98.7).

(xv) ASTM UOP539-97 Refinery Gas Analysis by Gas Chromatography (incorporated 

by reference, see §98.7).

(xvi) GPA 2261-00 Analysis for Natural Gas and Similar Gaseous Mixtures by Gas 

Chromatography (incorporated by reference, see §98.7).

(xvii) ISO 3170: Petroleum Liquids—Manual sampling—Third Edition (incorporated by 

reference, see §98.7).

(xviii) ISO 3171: Petroleum Liquids—Automatic pipeline sampling—Second Edition 

(incorporated by reference, see §98.7).

§98.165 Procedures for estimating missing data.

A complete record of all measured parameters used in the GHG emissions calculations is 

required. Therefore, whenever a quality-assured value of a required parameter is unavailable 

(e.g., if a meter malfunctions during unit operation), a substitute data value for the missing 
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parameter must be used in the calculations as specified in paragraphs (a), (b), and (c) of this 

section:

(a) For each missing value of the monthly fuel and feedstock consumption, the substitute 

data value must be the best available estimate of the fuel and feedstock consumption, based on 

all available process data (e.g., hydrogen production, electrical load, and operating hours). You 

must document and keep records of the procedures used for all such estimates.

(b) For each missing value of the carbon content or molecular weight of the fuel and 

feedstock, the substitute data value must be the arithmetic average of the quality-assured values 

of carbon contents or molecular weight of the fuel and feedstock immediately preceding and 

immediately following the missing data incident. If no quality-assured data on carbon contents or 

molecular weight of the fuel and feedstock are available prior to the missing data incident, the 

substitute data value must be the first quality-assured value for carbon contents or molecular 

weight of the fuel and feedstock obtained after the missing data period. You must document and 

keep records of the procedures used for all such estimates.

(c) For missing CEMS data, you must use the missing data procedures in §98.35.

§ 98.166 Data reporting requirements.

In addition to the information required by § 98.3(c), each annual report must contain the 

information specified in paragraphs (a) or (b) of this section, as appropriate, and paragraphs (c) 

through (e) of this section:

(a) If a CEMS is used to measure CO2 emissions, then you must report the relevant 

information required under § 98.36 for the Tier 4 Calculation Methodology and the following 

information in this paragraph (a):

(1) Unit identification number and annual CO2 emissions.
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(2) Annual quantity of hydrogen produced (metric tons) for each process unit.

(3) Annual quantity of ammonia produced (metric tons), if applicable, for each process 

unit.

(b) If a CEMS is not used to measure CO2 emissions, then you must report the following 

information for each hydrogen production process unit:

(1) Unit identification number and annual CO2 emissions.

(2) Reserved.

(3) Annual quantity of hydrogen produced (metric tons).

(4) Annual quantity of ammonia intentionally produced as a desired product, if applicable 

(metric tons).

(5) Reserved.

(6) Reserved.

(7) Name and annual quantity (metric tons) of each carbon-containing fuel and feedstock.

(c) Quantity of CO2 collected and transferred off site in either gas, liquid, or solid forms, 

following the requirements of subpart PP of this part.

(d) Annual quantity of carbon other than CO2 collected and transferred off site in either 

gas, liquid, or solid forms (kg carbon), excluding methanol.

(e) Annual quantity of methanol intentionally produced as a desired product, if 

applicable, (metric tons) for each process unit.

§ 98.167 Records that must be retained.

In addition to the information required by § 98.3(g), you must retain the records specified 

in paragraphs (a) through (e) of this section for each hydrogen production facility.
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(a) If a CEMS is used to measure CO2 emissions, then you must retain under this subpart 

the records required for the Tier 4 Calculation Methodology in § 98.37.

(b) If a CEMS is not used to measure CO2 emissions, then you must retain records of all 

analyses and calculations conducted as listed in §§ 98.166(b), (c), and (d).

(c) For units using the calculation methodologies described in § 98.163(b), the records 

required under § 98.3(g) must include both the company records and a detailed explanation of 

how company records are used to estimate the following:

(1) Fuel and feedstock consumption, when solid fuel and feedstock is combusted and a 

CEMS is not used to measure GHG emissions.

(2) Fossil fuel consumption, when, pursuant to § 98.33(e), the owner or operator of a unit 

that uses CEMS to quantify CO2 emissions and that combusts both fossil and biogenic fuels 

separately reports the biogenic portion of the total annual CO2 emissions.

(3) Sorbent usage, if the methodology in § 98.33(d) is used to calculate CO2 emissions 

from sorbent.

(d) The owner or operator must document the procedures used to ensure the accuracy of 

the estimates of fuel and feedstock usage and sorbent usage (as applicable) in § 98.163(b), 

including, but not limited to, calibration of weighing equipment, fuel and feedstock flow meters, 

and other measurement devices. The estimated accuracy of measurements made with these 

devices must also be recorded, and the technical basis for these estimates must be provided.

(e) Verification software records. You must keep a record of the file generated by the 

verification software specified in § 98.5(b) for the applicable data specified in paragraphs (e)(1) 

through (12) of this section. Retention of this file satisfies the recordkeeping requirement for the 

data in paragraphs (e)(1) through (12) of this section.
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(1) Indicate whether the monthly consumption of each gaseous fuel or feedstock is 

measured as mass or volume (Equation P-1 of § 98.163).

(2) Monthly volume of the gaseous fuel or feedstock (scf at standard conditions of 68 °F

and atmospheric pressure) (Equation P-1).

(3) Monthly mass of the gaseous fuel or feedstock (kg of fuel or feedstock) (Equation P1).

(4) Average monthly carbon content of the gaseous fuel or feedstock (kg C per kg of fuel 

or feedstock) (Equation P-1).

(5) Average monthly molecular weight of the gaseous fuel or feedstock (kg/kg-mole) 

(Equation P-1).

(6) Indicate whether the monthly consumption of each liquid fuel or feedstock is 

measured as mass or volume (Equation P-2 of § 98.163).

(7) Monthly volume of the liquid fuel or feedstock (gallons of fuel or feedstock) 

(Equation P-2).

(8) Monthly mass of the liquid fuel or feedstock (kg of fuel or feedstock) (Equation P-2).

(9) Average monthly carbon content of the liquid fuel or feedstock (kg C per gallon of 

fuel or feedstock) (Equation P-2).

(10) Average monthly carbon content of the liquid fuel or feedstock (kg C per kg of fuel 

or feedstock) (Equation P-2).

(11) Monthly mass of solid fuel or feedstock (kg of fuel and feedstock) (Equation P-3 of 

§ 98.163).

(12) Average monthly carbon content of the solid fuel or feedstock (kg C per kg of fuel 

and feedstock) (Equation P-3).
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§98.168 Definitions.

All terms used in this subpart have the same meaning given in the Clean Air Act and 

subpart A of this part.