Subpart W Flares and Flare Stacks

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This page provides an overview of the reporting requirements for the flare stacks source type for Subpart W. 

Please see Please see Reporting Form Instructions instructions on  on downloading the blank reporting form and uploading the completed reporting form.
You may also refer to to Optional Calculation Spreadsheet Instructions to  to download the Subpart W calculation spreadsheet.

This page provides an overview of the Subpart W e-GGRT reporting requirements for the flare stacks source category and emissions from flares.

The flare stack emissions category source type is applicable to Onshore Petroleum and Natural Gas Production and Onshore Natural Gas Processing segmentspetroleum and natural gas production (98.236(a)(2)), Onshore natural gas processing (98.236(a)(3)), Onshore natural gas transmission compression (98.236(a)(4)), Underground natural gas storage (98.236(a)(5)), Liquefied Natural Gas storage (98.236(a)(6)), LNG import and export equipment (98.236(a)(7)), and Onshore petroleum and natural gas gathering and boosting (98.236(a)(9)) facilities.

Emissions from flares at subpart W facilities are reportable under one of three authorities within part 98, including:

  • Flare stack emissions, as calculated under §9898.233(n), are a reportable source for Onshore Petroleum and Natural Gas Production facilities and Natural Gas Processing facilities, per §98.232(c)(9) and §98.232(d)(6), respectivelyOnshore petroleum and natural gas production (per 98.232(c)(9)) facilities, Onshore natural gas processing facilities (per 98.232(d)(6)), Onshore natural gas transmission compression (per 98.232(e)(6)), Underground natural gas storage (per 98.232(f)(4)), LNG storage (per 98.232(g)(4)), LNG import and export equipment (per 98.232(h)(5)), and Onshore petroleum and natural gas gathering and boosting (per 98.232(j)(7)) facilities.
  • Source-specific flared Source-specific “vented to flare” emissions reporting; as specified in §9898.236 for dehydrators (98.236(e)), well completions and workovers with hydraulic fracturing (98.236(g)), gas well completions and workovers , gas from produced oil without hydraulic fracturing (98.236(h)), hydrocarbon liquids sent to atmospheric tanks (98.236(j)), transmission tanks (98.236(k)), well testing (98.236(l)), and associated gas venting and flaring , centrifugal compressors, and reciprocating compressors(98.236(m)); and
  • For Offshore Petroleum and Natural Gas Production facilities, per §9898.236232(b), emissions from flares are reported separately on the Offshore Emission Source tab.

Because flare stack emission emissions at Subpart W facilities are potentially reported in a number of places, the EPA has offered the following simple hierarchy among the reporting categories to ensure that emissions from flares are not double counted per 98.233(n)(109):

  1. If emissions are reported under a source-specific “vented to flare” flared reporting categorytype, as list listed above, those specific emissions should be reported under that source and not reported elsewhere under the flare stacks emission source per 98.233(n) in the facility’s annual GHG reportingreport.

  2. Flare  Flare stack emission at Onshore Petroleum and Natural Gas Production facilities and Natural Gas Processing facilities that Onshore petroleum and natural gas production, Onshore natural gas processing, Onshore natural gas transmission compression, Underground natural gas storage, LNG storage, LNG import and export equipment, and Onshore petroleum and natural gas gathering and boosting facilities that are not captured under item (1) should be reported under the flare stack emission per §9898.233(n). To the extent that monitoring information includes amounts associated with reported emission under (1), those emissions should be deducted from the total emissions reported according to the methods in §9898.233(n). If all emissions are deducted, then report 0 for the emissions and report all of the other required data elements. 
Note

Flares that are not associated with onshore petroleum and natural gas production, onshore natural gas processing, onshore natural gas transmission compression, underground natural gas storage, LNG storage, LNG import and export equipment, onshore petroleum and natural gas gathering and boosting, or offshore petroleum and natural gas production facilities and not associated specific source types are exempt under Subpart C (§9898.30(a)(4)) and not required to be reported.

Please refer to to FAQ 667 for  for further information on the applicability of combustion emissions at Subpart W facilities.The reporting of flare stack emissions on the Flare Stacks tab in the Subpart W Reporting Form is composed of several elements as follows:

Indicate if the facility has the source type via the radio buttons.

If the source type is present you must report required

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elements

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If the facility has the source type,

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then indicate whether missing data procedures were used.

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Reporting Requirements

Table N.1  Flare Stacks required data elements include:

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For each flare, the facility is required to report:

  • Unique name or ID number for the flare stack (98.236(c)(12)(x)) - this data element is only required for Onshore Natural Gas Processing facilitiesn)(1))
  • Were CEMS used to measure CO2 emissions for the flare stack? (98.236(n)(8) and (12))
    • If Yes, report CO2 emissions (mt CO2) (98.236(n)(9))
      • Do not report data for the remaining emissions and activity data fields
    • If No, report:
      • Does the flare have a continuous flow monitor?
    (Yes or No)
      • (98.236(n)(2))
      • Does the flare have a continuous gas analyzer? (98.236(
    c)(12)(i
      • n)(3))
      • Volume of gas sent to flare (standard cubic feet) (98.236(n)(4))
    Percent
      • Fraction of feed gas sent to un-lit flare
    determine by engineering estimate and process knowledge based on best available data and operating records
      • (98.236
    (c)(12)(iii))Does the flare have a continuous gas analyzer? (Yes or No) (
      • (n)(5))
      • Flare combustion efficiency (decimal value) (98.236(n)(6))
      • Mole fraction of CH4 in flare feed gas (98.236(
    c
      • n)(
    12
      • 7)
    (iv
      • )
    )Were CEMS used to measure CO2 emissions for the flare stack? (Yes or No) (
      • Mole fraction of CO2 in flare feed gas (98.236(
    c
      • n)(
    12)(xi))
      • 8))
      • CO2 emissions (mt CO2
    • If Yes, the facility must report:
      • If CEMS were used, combusted and uncombusted CO2 (98.236(cn)(12)(iii))
      • Do not report data for the remaining fields
      If No, the facility must report:
      • 9))
      • CH4 emissions (mt CH4
      • Uncombusted CO2 emissions (98.236(cn)(12)(vii10))Uncombusted CH4 emissions
      • N2O emissions (mt N2O) (98.236(cn)(12)(vi))
      • Combusted CO2 emissions (98.236(c)(12)(viii))
      • N2O emissions (98.236(c)(12)(ix))
      • Do not report data for "If CEMS were used, combusted and uncombusted CO2"

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      • 11))

Note that reported CO2, CH4, and N2O emissions should reflect the total emissions after subtracting the amounts reported as flared emissions for other emission source types.

 

Table N.1  Flare Stacks

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Enlarge View of Table N.1  Flare Stacks

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Enlarge View of Table N.1  Flare Stacks (continued)

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Table N.2 Missing data procedures used for Flare Stacks emission calculations is required if your facility relied on missing data procedures to develop data elements used in calculating emissions for flare stacks:

  • Unique name or ID number for the flare stack
  • Parameters 

  • Measurement Frequency
  • Number of quarters missing data procedures were used [98.236(bb)(1)] (required only if the measurement frequency was quarterly)

  • Total number of hours in the year missing data procedure was used [98.3(c)(8)], [98.236(bb)(2)] (required unless the measurement frequency was quarterly, annually, biannually, or N/A)

  • Procedures used for missing data [98.235(h)]

Table N.2 Missing data procedures used for Flare Stacks emission calculations

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Total Emissions

The total emissions roll-up at the top of the sheet reflects the sum of each gas emission reported for the source type. These summations are calculated automatically by the Smart Form and tabulated on the Introduction tab.

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