Prior Year - Centrifugal Compressors

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

This page provides an overview of the Subpart W centrifugal compressor source category e-GGRT reporting requirements.

The centrifugal compressor source category is applicable to Onshore Petroleum Natural Gas Production, Onshore Natural Gas Processing, Onshore Natural Gas Transmission Compression, Underground Natural Gas Storage, Liquefied Natural Gas (LNG) Storage, and LNG Import and Export Equipment.

Indicate if the facility has the source type via the radio buttons.
  • If the source type is present you must report required elements.
If the facility has the source type, the Best Available Monitoring Methods and Missing Data table must be completed.
Centrifugal Compressor Reporting (Onshore Petroleum and Natural Gas Production)

The reporting requirements for Onshore Petroleum and Natural Gas Production differ from the rest of the industry segments for this subpart. For Onshore Petroleum and Natural Gas Production, only the following data elements are required to be reported:

  • The total annual CO2 emissions from all compressors combined, in metric tons CO2 [98.236(c)(13)(v)(B)]
  • The total annual CH4 emissions from all compressors combined, in metric tons CO2e [98.236(c)(13)(v)(B)]
  • Count of compressors (98.236(c)(13)(v)(A))

Centrifugal Compressor Reporting (Onshore Natural Gas Processing, Onshore Natural Gas Transmission Compression, Underground Natural Gas Storage, Liquefied Natural Gas (LNG) Storage, and LNG Import and Export Equipment)

All applicable industry segments other than Onshore Petroleum and Natural Gas Production must report emissions individually for each centrifugal compressor.

For each compressor, emissions will be reported by mode of operation and by specific source type. Two modes of operation that require emission monitoring are the operating mode, and the not operating, depressurized mode. Compressors that were in operating mode and have wet seal vents must report emissions from the wet seal vents. Compressors that were in operating mode with wet or dry seal vents must report emissions from blowdown vents. Compressors with wet or dry seal vents that were in the not operating, depressurized mode must report emissions from unit isolation valve leakage. Emissions from each mode of operation must be reported if the compressor was ever in that mode at any time during the year.

For each emission source, there are separate reporting fields for if the emission source was measured during the year (Equation W-22) or if the emission source was not measured and a default emission factor was applied (Equations W-23 and W-24). If one or more sources for a compressor were measured during the year, the emissions should be filled in for the respective measured fields. For any sources that emissions were not directly measured, the not measured field should be reported in place of the measured fields. If BAMM was used and no emission sources were measured, the compressor specific BAMM field should be reported as “yes”, and only the not measured emission fields should be reported. If BAMM was not used in place of direct measurement of at least one mode, then “no” should be entered for the BAMM field. The measured and not measured fields should never both be populated for a given compressor and source type.

The exact reporting requirements are described below:

Operating Mode
(required if compressor was ever in that operating
mode at any time during the year)


Required Data Elements

All Compressors

  • Compressor ID
  • Were BAMM Used for This Compressor? (Yes or No)
  • Seal Type (wet or dry)
  • Total annual CO2 emissions from all modes of operation combined in metric tons CO2 (98.236(c)(13)(iv))
  • Total annual CH4 emissions from all modes of operation combined in metric tons CO2e (98.236(c)(13)(iv))
  • Total annual N2O emissions from all modes of operation combined (mt CO2e) (98.236(c))

Operating Mode with Wet Seals



  • Annual throughput using an engineering calculation based on best available data (MMscf)(98.236(c)(13)(i)(C))
  • Number of wet seals connected to the degassing vent (98.236(c)(13)(i)(A))
  • Type of meter used for making measurements (98.236(c)(13)(i)(D))
  • Fraction of vent gas recovered for fuel (98.236(c)(13)(i)(B))
  • Fraction of vent gas recovered for sales (98.236(c)(13)(i)(B))
  • Fraction of vent gas recovered and flared (98.236(c)(13)(i)(B))   
  • Measured OR Not Measured seal vent CO2 emissions in metric tons CO2 (98.236(c)(13)(i)(G))
  • Measured OR Not Measured seal vent CH4 emissions in metric tons CO2e (98.236(c)(13)(i)(G))
  • Measured  OR Not Measured blowdown vent CO2 emissions in metric tons CO2 (98.236(c)(13)(ii)(C))
  • Measured OR Not Measured blowdown vent CH4 emissions in metric tons CO2e (98.236(c)(13)(ii)(C))

Operating Mode with Dry Seals

  • Measured  OR Not Measured blowdown vent CO2 emissions in metric tons CO2 (98.236(c)(13)(ii)(C))
  • Measured OR Not Measured blowdown vent CH4 emissions in metric tons CO2e (98.236(c)(13)(ii)(C))

Not Operating, Depressurized Mode with Wet or Dry Seals

  • Measured OR  Not Measured isolation valve leakage CO2 emissions in metric tons CO2 (98.236(c)(13)(ii)(C))
  • Measured OR Not Measured isolation valve leakage CH4 emissions in metric tons CO2e (98.236(c)(13)(ii)(C))

For Centrifugal Compressors Venting Emissions to FLARES

  • Did this compressor vent emissions to a flare? (98.236(c))
  • Total annual CO2 emissions from flaring for all modes of operation combined (mt CO2) (98.236(c))
  • Total annual CH4 emissions from flaring for all modes of operation combined
    (mt CO2e) (98.236(c))
  • Total annual N2O emissions from flaring for all modes of operation combined(mt CO2e) (98.236(c))

 

 For Centrifugal Compressors in OPERATING MODE

  • Total time in operating mode (hours) (98.236(c)(13)(i )(F)) (98.236(c)(13)(ii)(A))
  • Reporter emission factor for wet seal oil degassing vents (standard cubic feet per hour) (98.236(c)(13)(i )(E))
  • Reporter emission factor for blowdown vents (standard cubic feet per hour) (98.236(c)(13)(ii)(B))

 For Centrifugal Compressors in SHUTDOWN, DEPRESSURIZED MODE

  • Total time in shutdown, depressurized mode (hours) (98.236(c)(iii)(A))
  • Reporter emission factor for isolation valve emissions (standard cubic feet per hour) (98.236(c)(13)(iii)(B))

Total Emissions

The total emissions roll-up at the top of the sheet reflects the sum of the CO2 equivalents of each gas emission reported for the source type.  These summations are reflected and aggregated on the Introduction tab.

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