Subpart PP—Suppliers of Carbon Dioxide

§ 98.420 Definition of the source category.

(a) The carbon dioxide (CO2) supplier source category 

consists of the following:

(1) Facilities with production process units that capture a 

CO2 stream for purposes of supplying CO2 for commercial 

applications or that capture and maintain custody of a CO2 stream 

in order to sequester or otherwise inject it underground. 

Capture refers to the initial separation and removal of CO2 from 

a manufacturing process or any other process.

(2) Facilities with CO2 production wells that extract or 

produce a CO2 stream for purposes of supplying CO2 for commercial 

applications or that extract and maintain custody of a CO2 stream 

in order to sequester or otherwise inject it underground.

(3) Importers or exporters of bulk CO2.

(b) This source category is focused on upstream supply. It 

does not cover:

(1) Storage of CO2 above ground or in geologic formations.

(2) Use of CO2 in enhanced oil and gas recovery.

(3) Transportation or distribution of CO2.

(4) Purification, compression, or processing of CO2.

(5) On-site use of CO2 captured on site.

(c) This source category does not include CO2 imported or 

exported in equipment, such as fire extinguishers.
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§ 98.421 Reporting threshold.

Any supplier of CO2 who meets the requirements of 

§98.2(a)(4) of subpart A of this part must report the mass of CO2

captured, extracted, imported, or exported.

§ 98.422 GHGs to report.

(a) Mass of CO2 captured from production process units.

(b) Mass of CO2 extracted from CO2 production wells.

(c) Mass of CO2 imported.

(d) Mass of CO2 exported.

§ 98.423 Calculating CO2 supply.

(a) Except as allowed in paragraph (b) of this section, 

calculate the annual mass of CO2 captured, extracted, imported, 

or exported through each flow meter in accordance with the 

procedures specified in either paragraph (a)(1) or (a)(2) of 

this section. If multiple flow meters are used, you shall 

calculate the annual mass of CO2 for all flow meters according to 

the procedures specified in paragraph (a)(3) of this section.

(1) For each mass flow meter, you shall calculate quarterly 

the mass of CO2 in a CO2 stream in metric tons by multiplying the 

mass flow by the composition data, according to Equation PP–1 of 

this section. Mass flow and composition data measurements shall 

be made in accordance with §98.424 of this subpart.
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Where:

CO2,u = Annual mass of CO2 (metric tons) through flow 

meter u.

CCO2,p,u = Quarterly CO2 concentration measurement in flow 

for flow meter u in quarter p (wt. %CO2).

Qp,u = Quarterly mass flow rate measurement for flow 

meter u in quarter p (metric tons).

p = Quarter of the year.

u = Flow meter.

(2) For each volumetric flow meter, you shall calculate 

quarterly the mass of CO2 in a CO2 stream in metric tons by 

multiplying the volumetric flow by the concentration and density 

data, according to Equation PP–2 of this section. Volumetric 

flow, concentration and density data measurements shall be made 

in accordance with §98.424 of this section.

Where:

CO2,u = Annual mass of CO2 (metric tons) through flow 

meter u.

CCO2,p = Quarterly CO2 concentration measurement in flow 

for flow meter u in quarter p (measured as either 

volume % CO2 or weight % CO2).

Qp = Quarterly volumetric flow rate measurement for 

flow meter u in quarter p (standard cubic meters).

Dp = Density of CO2 in quarter p (metric tons CO2 per 

standard cubic meter) for flow meter u if CCO2,pis 

measured as volume % CO2, or density of the whole 

CO2 stream for flow meter u (metric tons per 

standard cubic meter) if CCO2,p is measured as 

weight % CO2.
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p = Quarter of the year.

u = Flow meter.

(3) To aggregate data, use either Equation PP–3a or PP–3b 

in this paragraph, as appropriate.

(i) For facilities with production process units or 

production wells that capture or extract a CO2 stream and either 

measure it after segregation or do not segregate the flow, 

calculate the total CO2 supplied in accordance with Equation PP–

3a.

Where:

CO2 = Total annual mass of CO2 (metric tons).

CO2,u = Annual mass of CO2 (metric tons) through flow 

meter u.

u = Flow meter.

(ii) For facilities with production process units that 

capture a CO2 stream and measure it ahead of segregation, 

calculate the total CO2 supplied in accordance with Equation PP–

3b.

Where:

CO2 = Total annual mass of CO2 (metric tons).

CO2,u = Annual mass of CO2 (metric tons) through main 

flow meter u.

CO2,v = Annual mass of CO2 (metric tons) through 

subsequent flow meter v for use on site.
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u = Main flow meter.

v = Subsequent flow meter.

(b) As an alternative to paragraphs (a)(1) through (3) of 

this section for CO2 that is supplied in containers, calculate 

the annual mass of CO2 supplied in containers delivered by each 

CO2 stream in accordance with the procedures specified in either 

paragraph (b)(1) or (b)(2) of this section. If multiple CO2

streams are used to deliver CO2 to containers, you shall 

calculate the annual mass of CO2 supplied in containers delivered 

by all CO2 streams according to the procedures specified in 

paragraph (b)(3) of this section.

(1) For each CO2 stream that delivers CO2 to containers, for 

which mass is measured, you shall calculate CO2 supply in 

containers using Equation PP–1 of this section.

Where:

CO2,u = Annual mass of CO2 (metric tons) supplied in 

containers delivered by CO2 stream u.

CCO2,p,u = Quarterly CO2 concentration measurement of CO2

stream u that delivers CO2 to containers in 

quarter p (wt. %CO2).

Qp,u = Quarterly mass of contents supplied in all 

containers delivered by CO2 stream u in quarter p 

(metric tons).

p = Quarter of the year.

u = CO2 stream that delivers to containers.
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(2) For each CO2 stream that delivers to containers, for 

which volume is measured, you shall calculate CO2 supply in 

containers using Equation PP–2 of this section.

Where:

CO2,u = Annual mass of CO2 (metric tons) supplied in 

containers delivered by CO2 stream u.

CCO2,p = Quarterly CO2 concentration measurement of CO2

stream u that delivers CO2 to containers in quarter 

p (measured as either volume % CO2 or weight % 

CO2).

Qp = Quarterly volume of contents supplied in all 

containers delivered by CO2 stream u in quarter p 

(standard cubic meters).

Dp = Quarterly CO2 density determination for CO2 stream 

u in quarter p (metric tons per standard cubic 

meter) if CO2,pis measured as volume % CO2, or 

density of CO2 stream u (metric tons per standard 

cubic meter) if CO2,pis measured as weight % CO2.

p = Quarter of the year.

u = CO2 stream that delivers to containers.

(3) To aggregate data, sum the mass of CO2 supplied in 

containers delivered by all CO2 streams in accordance with 

Equation PP–3a of this section.

Where:

CO2 = Annual mass of CO2 (metric tons) supplied in 

containers delivered by all CO2 streams.

CO2,u = Annual mass of CO2 (metric tons) supplied in 

containers delivered by CO2 stream u.

u = CO2 stream that delivers to containers.

(c) Importers or exporters that import or export CO2 in 

containers shall calculate the total mass of CO2 imported or 
Page 7 of 18

exported in metric tons based on summing the mass in each CO2

container using weigh bills, scales, or load cells according to 

Equation PP–4 of this section.

Where:

CO2 = Annual mass of CO2 (metric tons).

Q = Annual mass in all CO2 containers imported or 

exported during the reporting year (metric tons).

§ 98.424 Monitoring and QA/QC requirements.

(a) Determination of quantity.

(1) Reporters following the procedures in §98.423(a) shall 

determine quantity using a flow meter or meters located in 

accordance with this paragraph.

(i) If the CO2 stream is segregated such that only a portion 

is captured for commercial application or for injection, you 

must locate the flow meter according to the following:

(A) For reporters following the procedures in 

§98.423(a)(3)(i), you must locate the flow meter(s) after the 

point of segregation.

(B) For reporters following the procedures in paragraph 

(a)(3)(ii) of §98.423, you must locate the main flow meter(s) on 

the captured CO2 stream(s) prior to the point of segregation and 

the subsequent flow meter(s) on the CO2 stream(s) for on-site use 

after the point of segregation. You may only follow the 
Page 8 of 18

procedures in paragraph (a)(3)(ii) of §98.423 if the CO2

stream(s) for on-site use is/are the only diversion(s) from the 

main, captured CO2 stream(s) after the main flow meter 

location(s).

(ii) Reporters that have a mass flow meter or volumetric 

flow meter installed to measure the flow of a CO2 stream that 

meets the requirements of paragraph (a)(1)(i) of this section 

shall base calculations in §98.423 of this subpart on the 

installed mass flow or volumetric flow meters.

(iii) Reporters that do not have a mass flow meter or 

volumetric flow meter installed to measure the flow of the CO2

stream that meets the requirements of paragraph (a)(1)(i) of 

this section shall base calculations in §98.423 of this subpart

on the flow of gas transferred off site using a mass flow meter 

or a volumetric flow meter located at the point of off-site 

transfer.

(2) Reporters following the procedures in paragraph (b) of 

§98.423 shall determine quantity in accordance with this 

paragraph.

(i) Reporters that supply CO2 in containers using weigh 

bills, scales, or load cells shall measure the mass of contents 

of each CO2 container to which the CO2 stream is delivered, sum 

the mass of contents supplied in all containers to which the CO2

stream is delivered during each quarter, sample the CO2 stream 
Page 9 of 18

delivering CO2 to containers on a quarterly basis to determine 

the composition of the CO2 stream, and apply Equation PP–1.

(ii) Reporters that supply CO2 in containers using loaded 

container volumes shall measure the volume of contents of each 

CO2 container to which the CO2 stream is delivered, sum the 

volume of contents supplied in all containers to which the CO2

stream is delivered during each quarter, sample the CO2 stream on 

a quarterly basis to determine the composition of the CO2 stream, 

determine the density quarterly, and apply Equation PP–2.

(3) Importers or exporters that import or export CO2 in 

containers shall measure the mass in each CO2 container using 

weigh bills, scales, or load cells and sum the mass in all 

containers imported or exported during the reporting year.

(4) All flow meters, scales, and load cells used to measure 

quantities that are reported in §98.423 of this subpart shall be 

operated and calibrated according to the following procedure:

(i) You shall use an appropriate standard method published 

by a consensus-based standards organization if such a method 

exists. Consensus-based standards organizations include, but are 

not limited to, the following: ASTM International, the American 

National Standards Institute (ANSI), the American Gas 

Association (AGA), the American Society of Mechanical Engineers 

(ASME), the American Petroleum Institute (API), and the North 

American Energy Standards Board (NAESB).
Page 10 of 18

(ii) Where no appropriate standard method developed by a 

consensus-based standards organization exists, you shall follow 

industry standard practices.

(iii) You must ensure that any flow meter calibrations 

performed are NIST traceable.

(5) Reporters using Equation PP–2 of this subpart and 

measuring CO2 concentration as weight % CO2 shall determine the 

density of the CO2 stream on a quarterly basis in order to 

calculate the mass of the CO2 stream according to one of the 

following procedures:

(i) You may use a method published by a consensus-based 

standards organization. Consensus-based standards organizations 

include, but are not limited to, the following: ASTM 

International (100 Barr Harbor Drive, P.O. Box CB700, West 

Conshohocken, Pennsylvania 19428–B2959, (800) 262–1373, 

http://www.astm.org ), the American National Standards Institute 

(ANSI, 1819 L Street, NW., 6th floor, Washington, DC 20036, 

(202) 293–8020, http://www.ansi.org ), the American Gas 

Association (AGA, 400 North Capitol Street, NW., 4th Floor, 

Washington, DC 20001, (202) 824–7000, http://www.aga.org ), the 

American Society of Mechanical Engineers (ASME, Three Park 

Avenue, New York, NY 10016–5990, (800) 843–2763, 

http://www.asme.org ), the American Petroleum Institute (API, 

1220 L Street, NW., Washington, DC 20005–4070, (202) 682–8000, 
Page 11 of 18

http://www.api.org ), and the North American Energy Standards 

Board (NAESB, 801 Travis Street, Suite 1675, Houston, TX 77002, 

(713) 356–0060, http://www.api.org ). The method(s) used shall 

be documented in the Monitoring Plan required under §98.3(g)(5).

(ii) You may follow an industry standard method.

(b) Determination of concentration. (1) Reporters using 

Equation PP–1 or PP–2 of this subpart shall sample the CO2 stream 

on a quarterly basis to determine the composition of the CO2

stream.

(2) Methods to measure the composition of the CO2 stream 

must conform to applicable chemical analytical standards. 

Acceptable methods include, but are not limited to, the U.S. 

Food and Drug Administration food-grade specifications for CO2

(see 21 CFR 184.1240) and ASTM standard E1747–95 (Reapproved 

2005) Standard Guide for Purity of Carbon Dioxide Used in 

Supercritical Fluid Applications (ASTM International, 100 Barr 

Harbor Drive, P.O. Box CB700, West Conshohocken, Pennsylvania 

19428–B2959, (800) 262–1373, http://www.astm.org ).

(c) You shall convert the density of the CO2 stream(s) and 

all measured volumes of carbon dioxide to the following standard 

industry temperature and pressure conditions: Standard cubic 

meters at a temperature of 60 degrees Fahrenheit and at an 

absolute pressure of 1 atmosphere. If you apply the density 
Page 12 of 18

value for CO2 at standard conditions, you must use 0.001868 

metric tons per standard cubic meter.

§ 98.425 Procedures for estimating missing data.

(a) Whenever the quality assurance procedures in 

§98.424(a)(1) of this subpart cannot be followed to measure 

quarterly mass flow or volumetric flow of CO2, the most 

appropriate of the following missing data procedures shall be 

followed:

(1) A quarterly CO2 mass flow or volumetric flow value that 

is missing may be substituted with a quarterly value measured 

during another quarter of the current reporting year.

(2) A quarterly CO2 mass flow or volumetric flow value that 

is missing may be substituted with a quarterly value measured 

during the same quarter from the past reporting year.

(3) If a mass or volumetric flow meter is installed to 

measure the CO2 stream, you may substitute data from a mass or 

volumetric flow meter measuring the CO2 stream transferred for 

any period during which the installed meter is inoperable.

(4) The mass or volumetric flow used for purposes of 

product tracking and billing according to the reporter's 

established procedures may be substituted for any period during 

which measurement equipment is inoperable.

(b) Whenever the quality assurance procedures in §98.424(b) 

of this subpart cannot be followed to determine concentration of 
Page 13 of 18

the CO2 stream, the most appropriate of the following missing 

data procudures shall be followed:

(1) A quarterly concentration value that is missing may be 

substituted with a quarterly value measured during another 

quarter of the current reporting year.

(2) A quarterly concentration value that is missing may be 

substituted with a quarterly value measured during the same 

quarter from the previous reporting year.

(3) The concentration used for purposes of product tracking 

and billing according to the reporter's established procedures 

may be substituted for any quarterly value.

(c) Missing data on density of the CO2 stream shall be 

substituted with quarterly or annual average values from the 

previous calendar year.

(d) Whenever the quality assurance procedures in 

§98.424(a)(2) of this subpart cannot be followed to measure 

quarterly quantity of CO2 in containers, the most appropriate of 

the following missing data procedures shall be followed:

(1) A quarterly quantity of CO2 in containers that is 

missing may be substituted with a quarterly value measured 

during another representative quarter of the current reporting 

year.
Page 14 of 18

(2) A quarterly quantity of CO2 in containers that is 

missing may be substituted with a quarterly value measured 

during the same quarter from the past reporting year.

(3) The quarterly quantity of CO2 in containers recorded for 

purposes of product tracking and billing according to the 

reporter's established procedures may be substituted for any 

period during which measurement equipment is inoperable.

§ 98.426 Data reporting requirements.

In addition to the information required by §98.3(c) of 

subpart A of this part, the annual report shall contain the 

following information, as applicable:

(a) If you use Equation PP–1 of this subpart, report the 

following information for each mass flow meter or CO2 stream that 

delivers CO2 to containers:

(1) Annual mass in metric tons of CO2.

(2) Quarterly mass in metric tons of CO2.

(3) Quarterly concentration of the CO2 stream.

(4) The standard used to measure CO2 concentration.

(5) The location of the flow meter in your process chain in 

relation to the points of CO2 stream capture, dehydration, 

compression, and other processing.

(b) If you use Equation PP–2 of this subpart, report the 

following information for each volumetric flow meter or CO2

stream that delivers CO2 to containers:
Page 15 of 18

(1) Annual mass in metric tons of CO2.

(2) Quarterly volume in standard cubic meters of CO2.

(3) Quarterly concentration of the CO2 stream in volume or 

weight percent.

(4) Report density as follows:

(i) Quarterly density of the CO2 stream in metric tons per 

standard cubic meter if you report the concentration of the CO2

stream in paragraph (b)(3) of this section in weight percent.

(ii) Quarterly density of CO2 in metric tons per standard 

cubic meter if you report the concentration of the CO2 stream in 

paragraph (b)(3) of this section in volume percent.

(5) The method used to measure density.

(6) The standard used to measure CO2 concentration.

(7) The location of the flow meter in your process chain in 

relation to the points of CO2 stream capture, dehydration, 

compression, and other processing.

(c) For the aggregated annual mass of CO2 emissions 

calculated using Equation PP–3a or PP–3b, report the following:

(1) If you use Equation PP–3a of this subpart, report the 

annual CO2 mass in metric tons from all flow meters and CO2

streams that deliver CO2 to containers.

(2) If you use Equation PP–3b of this subpart, report:

(i) The total annual CO2 mass through main flow meter(s) in 

metric tons.
Page 16 of 18

(ii) The total annual CO2 mass through subsequent flow 

meter(s) in metric tons.

(iii) The total annual CO2 mass supplied in metric tons.

(iv) The location of each flow meter in relation to the 

point of segregation.

(d) If you use Equation PP–4 of this subpart, report at the 

corporate level the annual mass of CO2 in metric tons in all CO2

containers that are imported or exported.

(e) Each reporter shall report the following information:

(1) The type of equipment used to measure the total flow of 

the CO2 stream or the total mass or volume in CO2 containers.

(2) The standard used to operate and calibrate the 

equipment reported in (e)(1) of this section.

(3) The number of days in the reporting year for which 

substitute data procedures were used for the following purpose:

(i) To measure quantity.

(ii) To measure concentration.

(iii) To measure density.

(f) Report the aggregated annual quantity of CO2 in metric 

tons that is transferred to each of the following end use 

applications, if known:

(1) Food and beverage.

(2) Industrial and municipal water/wastewater treatment.

(3) Metal fabrication, including welding and cutting.
Page 17 of 18

(4) Greenhouse uses for plant growth.

(5) Fumigants (e.g., grain storage) and herbicides.

(6) Pulp and paper.

(7) Cleaning and solvent use.

(8) Fire fighting.

(9) Transportation and storage of explosives.

(10) Injection of carbon dioxide for enhanced oil and 

natural gas recovery that is covered by subpart UU of this part.

(11)Geologic sequestration of carbon dioxide that is 

covered by subpart RR of this part.

(12) Research and development.

(13) Other.

(g) Each production process unit that captures a CO2 stream 

for purposes of supplying CO2 for commercial applications or in 

order to sequester or otherwise inject it underground when 

custody of the CO2 is maintained shall report the percentage of 

that stream, if any, that is biomass-based during the reporting 

year.

§ 98.427 Records that must be retained.

In addition to the records required by §98.3(g) of subpart 

A of this part, you must retain the records specified in 

paragraphs (a) through (c) of this section, as applicable.
Page 18 of 18

(a) The owner or operator of a facility containing 

production process units must retain quarterly records of 

captured or transferred CO2 streams and composition.

(b) The owner or operator of a CO2 production well facility 

must maintain quarterly records of the mass flow or volumetric 

flow of the extracted or transferred CO2 stream and concentration 

and density if volumetric flow meters are used.

(c) Importers or exporters of CO2 must retain annual records 

of the mass flow, volumetric flow, and mass of CO2 imported or 

exported.

§ 98.428 Definitions.

All terms used in this subpart have the same meaning given 

in the Clean Air Act and subpart A of this part.