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Subpart UU—Injection of Carbon Dioxide

§ 98.470 Definition of the source category.

(a) The injection of carbon dioxide (CO2) source category 

comprises any well or group of wells that inject a CO2 stream 

into the subsurface.

(b) If you report under subpart RR of this part for a well 

or group of wells, you are not required to report under this 

subpart for that well or group of wells.

(c) A facility that is subject to this part only because it 

is subject to subpart UU of this part is not required to report 

emissions under subpart C of this part or any other subpart 

listed in §98.2(a)(1) or (a)(2).

§ 98.471 Reporting threshold.

(a) You must report under this subpart if your facility 

injects any amount of CO2 into the subsurface.

(b) For purposes of this subpart, any reference to CO2

emissions in §98.2(i) shall mean CO2 received.

§ 98.472 GHGs to report.

You must report the mass of CO2 received.

§ 98.473 Calculating CO2 received.

(a) You must calculate and report the annual mass of CO2

received by pipeline using the procedures in paragraphs (a)(1) 

or (a)(2) of this section and the procedures in paragraph (a)(3) 

of this section, if applicable.
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(1) For a mass flow meter, you must calculate the total 

annual mass of CO2 in a CO2 stream received in metric tons by 

multiplying the mass flow by the CO2 concentration in the flow, 

according to Equation UU–1 of this section. You must collect 

these data quarterly. Mass flow and concentration data 

measurements must be made in accordance with §98.474.

Where:

CO2 T,r = Net annual mass of CO2 received through flow 

meter r (metric tons).

Qr,p = Quarterly mass flow through a receiving flow 

meter r in quarter p (metric tons).

Sr,p = Quarterly mass flow through a receiving flow 

meter r that is redelivered to another 

facility without being injected into your well 

in quarter p (metric tons).

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

for flow meter r in quarter p (wt. percent CO2,

expressed as a decimal fraction).

p = Quarter of the year.

r = Receiving flow meter.

(2) For a volumetric flow meter, you must calculate the 

total annual mass of CO2 in a CO2 stream received in metric tons 

by multiplying the volumetric flow at standard conditions by the 

CO2 concentration in the flow and the density of CO2 at standard 

conditions, according to Equation UU–2 of this section. You must 

collect these data quarterly. Volumetric flow and concentration 

data measurements must be made in accordance with §98.474.
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Where:

CO2 T,r = Net annual mass of CO2 received through flow 

meter r (metric tons).

Qr,p = Quarterly volumetric flow through a receiving 

flow meter r in quarter p at standard 

conditions (standard cubic meters).

Sr,p = Quarterly volumetric flow through a receiving 

flow meter r that is redelivered to another 

facility without being injected into your well 

in quarter p (standard cubic meters).

D = Density of CO2 at standard conditions (metric 

tons per standard cubic meter): 0.0018682.

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

for flow meter r in quarter p (vol. percent 

CO2, expressed as a decimal fraction).

p = Quarter of the year.

r = Receiving flow meter.

(3) If you receive CO2 through more than one flow meter, you 

must sum the mass of all CO2 received in accordance with the 

procedure specified in Equation UU–3 of this section.

Where:

CO2 = Total net annual mass of CO2 received (metric 

tons).

CO2 T,r = Net annual mass of CO2 received (metric tons) 

as calculated in Equation UU–1 or UU–2 for 

flow meter r.

r = Receiving flow meter.
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(b) You must calculate and report the annual mass of CO2

received in containers using the procedures specified in either 

paragraph (b)(1) or (b)(2) of this section.

(1) If you are measuring the mass of contents in a 

container under the provisions of §98.474(a)(2)(i), you must 

calculate the CO2 received in containers using Equation UU–1 of 

this section.

Where:

CO2 T,r = Annual mass of CO2 received in containers r 

(metric tons).

CCO2,p,r = Quarterly CO2 concentration measurement of 

contents in containers r in quarter p (wt. 

percent CO2, expressed as a decimal fraction).

Qr,p = Quarterly mass of contents in containers r in 

quarter p (metric tons).

Sr,p = Quarterly mass of contents in containers r 

that is redelivered to another facility 

without being injected into your well in 

quarter p (standard cubic meters).

p = Quarter of the year.

r = Containers.

(2) If you are measuring the volume of contents in a 

container under the provisions of §98.474(a)(2)(ii), you must 

calculate the CO2 received in containers using Equation UU–2 of 

this section.

Where:

CO2 T,r = Annual mass of CO2 received in containers r 

(metric tons).
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CCO2,p,r = Quarterly CO2 concentration measurement of 

contents in containers r in quarter p (vol. 

percent CO2, expressed as a decimal fraction).

Sr,p = Quarterly volume of contents in containers r 

that is redelivered to another facility 

without being injected into your well in 

quarter p (standard cubic meters).

Qr,p = Quarterly volume of contents in containers r 

in quarter p (standard cubic meters).

D = Density of the CO2 received in containers at 

standard conditions (metric tons per standard 

cubic meter): 0.0018682.

p = Quarter of the year.

r = Containers.

§ 98.474 Monitoring and QA/QC requirements.

(a) CO2 received.

(1) You must determine the quarterly flow rate of CO2

received by pipeline by following the most appropriate of the 

following procedures:

(i) You may measure flow rate at the receiving custody 

transfer meter prior to any subsequent processing operations at 

the facility and collect the flow rate quarterly.

(ii) If you took ownership of the CO2 in a commercial 

transaction, you may use the quarterly flow rate data from the 

sales contract if it is a one-time transaction or from invoices 

or manifests if it is an ongoing commercial transaction with 

discrete shipments.

(iii) If you inject CO2 from a production process unit that 

is part of your facility, you may use the quarterly CO2 flow rate 
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that was measured at the equivalent of a custody transfer meter 

following procedures provided in subpart PP of this part. To be 

the equivalent of a custody transfer meter, a meter must measure 

the flow of CO2 being transported to an injection well to the 

same degree of accuracy as a meter used for commercial 

transactions.

(2) You must determine the quarterly mass or volume of 

contents in all containers if you receive CO2 in containers by 

the most appropriate of the following procedures:

(i) You may measure the mass of contents of containers 

summed quarterly using weigh bills, scales, or load cells.

(ii) You may determine the volume of the contents of 

containers summed quarterly.

(iii) If you took ownership of the CO2 in a commercial 

transaction, you may use the quarterly mass or volume of 

contents from the sales contract if it is a one-time transaction 

or from invoices or manifests if it is an ongoing commercial 

transaction with discrete shipments.

(3) You must determine a quarterly concentration of the CO2

received that is representative of all CO2 received in that 

quarter by following the most appropriate of the following 

procedures:

(i) You may sample the CO2 stream at least once per quarter 

at the point of receipt and measure its CO2 concentration.
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(ii) If you took ownership of the CO2 in a commercial 

transaction for which the sales contract was contingent on CO2

concentration, and if the supplier of the CO2 sampled the CO2

stream in a quarter and measured its concentration per the sales 

contract terms, you may use the CO2 concentration data from the 

sales contract for that quarter.

(iii) If you inject CO2 from a production process unit that 

is part of your facility, you may report the quarterly CO2

concentration of the CO2 stream supplied that was measured 

following procedures provided in subpart PP of this part as the 

quarterly CO2 concentration of the CO2 stream received.

(4) You must assume that the CO2 you receive meets the 

definition of a CO2 stream unless you can trace it through 

written records to a source other than a CO2 stream.

(b) Measurement devices. 

(1) All flow meters must be operated continuously except as 

necessary for maintenance and calibration.

(2) You must calibrate all flow meters used to measure 

quantities reported in §98.476 according to the calibration and 

accuracy requirements in §98.3(i).

(3) You must operate all measurement devices according to 

one of the following. You may use an appropriate standard method 

published by a consensus-based standards organization if such a 

method exists or an industry standard practice. Consensus-based 
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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).

(4) You must ensure that any flow meter calibrations 

performed are National Institute of Standards and Technology 

(NIST) traceable.

(c) General. 

(1) If you measure the concentration of any CO2 quantity for 

reporting, you must measure according to one of the following. 

You may use an appropriate standard method published by a 

consensus-based standards organization if such a method exists 

or an industry standard practice.

(2) You must convert all measured volumes of CO2 to the 

following standard industry temperature and pressure conditions 

for use in Equations UU–2 of this subpart: standard cubic meters 

at a temperature of 60 degrees Fahrenheit and at an absolute 

pressure of 1 atmosphere.

(3) For 2011, you may follow the provisions of §98.3(d)(1) 

through (2) for best available monitoring methods rather than

follow the monitoring requirements of this section. For purposes 
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of this subpart, any reference to the year 2010 in §98.3(d)(1) 

through (2) shall mean 2011.

§ 98.475 Procedures for estimating missing data.

A complete record of all measured parameters used in the 

GHG quantities calculations is required.

(a) Whenever the monitoring procedures for all facilities 

that used flow meters covered under this subpart cannot be 

followed to measure flow, the following missing data procedures 

must be followed:

(1) Another calculation methodology listed in §98.474(a)(1) 

must be used if possible.

(2) If another method listed in §98.474(a)(1) cannot be 

used, a quarterly flow rate value that is missing must be 

estimated using a representative flow rate value from the 

nearest previous time period.

(b) Whenever the monitoring procedures of this subpart 

cannot be followed to measure quarterly quantity of CO2 received 

in containers, the most appropriate of the following missing 

data procedures must be followed:

(1) Another calculation methodology listed in §98.474(a)(2) 

must be used if possible.

(2) If another method listed in §98.474(a)(2) cannot be 

used, a quarterly mass or volume that is missing must be 
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estimated using a representative mass or volume from the nearest 

previous time period.

(c) Whenever the monitoring procedures cannot be followed 

to measure CO2 concentration, the following missing data 

procedures must be followed:

(1) Another calculation methodology listed in §98.474(a)(3) 

must be used if possible.

(2) If another method listed in §98.474(a)(3) cannot be 

used, a quarterly concentration value that is missing must be 

estimated using a representative concentration value from the 

nearest previous time period.

§ 98.476 Data reporting requirements.

If you are subject to this part and report under this 

subpart, you are not required to report the information in 

§98.3(c)(4) for this subpart. In addition to the information 

required by §98.3(c)(1) through §98.3(c)(3) and by §98.3(c)(5) 

through §98.3(c)(9), you must report the information listed in 

this section.

(a) If you receive CO2 by pipeline, report the following for 

each receiving flow meter:

(1) The total net mass of CO2 received (metric tons) 

annually.

(2) If a volumetric flow meter is used to receive CO2 :
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(i) The volumetric flow through a receiving flow meter at 

standard conditions (in standard cubic meters) in each quarter.

(ii) The volumetric flow through a receiving flow meter 

that is redelivered to another facility without being injected 

into your well (in standard cubic meters) in each quarter.

(iii) The CO2 concentration in the flow (volume percent CO2

expressed as a decimal fraction) in each quarter.

(3) If a mass flow meter is used to receive CO2 :

(i) The mass flow through a receiving flow meter (in metric 

tons) in each quarter.

(ii) The mass flow through a receiving flow meter that is 

redelivered to another facility without being injected into your 

well (in metric tons) in each quarter.

(iii) The CO2 concentration in the flow (weight percent CO2

expressed as a decimal fraction) in each quarter.

(4) The standard or method used to calculate each value in 

paragraphs (a)(2) through (a)(3) of this section.

(5) The number of times in the reporting year for which 

substitute data procedures were used to calculate values 

reported in paragraphs (a)(2) through (a)(3) of this section.

(6) Whether the flow meter is mass or volumetric.

(b) If you receive CO2 in containers, report:
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(1) The mass (in metric tons) or volume at standard 

conditions (in standard cubic meters) of contents in containers 

in each quarter.

(2) The concentration of CO2 of contents in containers 

(volume or weight percent CO2 expressed as a decimal fraction) in 

each quarter.

(3) The mass (in metric tons) or volume (in standard cubic 

meters) of contents in containers that is redelivered to another 

facility without being injected into your well in each quarter.

(4) The net total mass of CO2 received (in metric tons) 

annually.

(5) The standard or method used to calculate each value in 

paragraphs (b)(1), (b)(2), and (b)(3) of this section.

(6) The number of times in the reporting year for which 

substitute data procedures were used to calculate values 

reported in paragraphs (b)(1) and (b)(2) of this section.

(c) If you use more than one receiving flow meter, report 

the net total mass of CO2 received (metric tons) through all flow 

meters annually.

(d) The source of the CO2 received according to the 

following categories:

(1) CO2 production wells.

(2) Electric generating unit.

(3) Ethanol plant.
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(4) Pulp and paper mill.

(5) Natural gas processing.

(6) Gasification operations.

(7) Other anthropogenic source.

(8) Discontinued enhanced oil and gas recovery project.

(9) Unknown.

(e) Report the following:

(1) Whether the facility received a Research and 

Development project exemption from reporting under 40 CFR part 

98, subpart RR, for this reporting year. If you received an 

exemption, report the start and end dates of the exemption 

approved by EPA;

(2) Whether the facility includes a well or group of wells 

where a CO2 stream was injected into subsurface geologic 

formations to enhance the recovery of oil during this reporting 

year;

(3) Whether the facility includes a well or group of wells 

where a CO2 stream was injected into subsurface geologic 

formations to enhance the recovery of natural gas during this 

reporting year;

(4) Whether the facility includes a well or group of wells 

where a CO2 stream was injected into subsurface geologic 

formations for acid gas disposal during this reporting year;
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(5) Whether the facility includes a well or group of wells 

where a CO2 stream was injected for a purpose other than those 

listed in paragraphs (e)(1) through (4) of this section. If you 

injected CO2 for another purpose, report the purpose of the 

injection.

§ 98.477 Records that must be retained.

(a) You must follow the record retention requirements 

specified by §98.3(g). In addition to the records required by 

§98.3(g), you must retain quarterly records of CO2 received, 

including mass flow rate or contents of containers (mass or 

volumetric) at standard conditions and operating conditions, 

operating temperature and pressure, and concentration of these 

streams. You must retain all required records for at least 3 

years.

(b) You must complete your monitoring plans, as described 

in §98.3(g)(5), by April 1 of the year you begin collecting 

data.

§ 98.478 Definitions.

Except as provided below, all terms used in this subpart 

have the same meaning given in the Clean Air Act and subpart A 

of this part.

CO2 received means the CO2 stream that you receive to be 

injected for the first time into a well on your facility that is 

covered by this subpart. CO2 received includes, but is not 
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limited to, a CO2 stream from a production process unit inside 

your facility and a CO2 stream that was injected into a well on 

another facility, removed from a discontinued enhanced oil or 

natural gas or other production well, and transferred to your 

facility.