California Code of Regulations
Title 17 - Public Health
Division 3 - Air Resources
Chapter 1 - Air Resources Board
Subchapter 10 - Climate Change
Article 2 - Mandatory Greenhouse Gas Emissions Reporting
Subarticle 5 - Reporting Requirements and Calculation Methods for Petroleum and Natural Gas Systems
Appendix A - to the Regulation for the Mandatory Reporting of Greenhouse Gas Emissions

Universal Citation: 17 CA Code of Regs A

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

Emission Factors and Calculation Data for Petroleum and Natural Gas Systems Reporting

Table 1A

Default Whole Gas Emission Factors for Onshore Petroleum and Natural Gas Production

*Onshore petroleum and natural gas production*		*Emission factor (scf/hour/ component)*
Western U.S.
Population Emission Factors All components, Gas Service:1
	Valve	0.121
	Connector	0.017
	Open-ended line	0.031
	Pressure relief valve	0.193
	Low Continuous Bleed Pneumatic Device Vents2	1.39
	High Continuous Bleed Pneumatic Device Vents2	37.3
	Intermittent Bleed Pneumatic Device Vents2	13.5
	Pneumatic Pumps3	13.3

Population Emission Factors -- All Components, Light Crude Service:4
	Valve	0.05
	Flange	0.003
	Connector	0.007
	Open-ended Line	0.05
	Pump	0.01
	Other5	0.30

Population Emission Factors -- All Components, Heavy Crude Service:6
	Valve	0.0005
	Flange	0.0009
	Connector (other)	0.0003
	Open-ended Line	0.006
	Other5	0.003

1 For multi-phase flow that includes gas, use the gas service emissions factors.

2 Emissions factor is in units of "scf/hour/device."

3 Emission Factor is in units of "scf/hour/pump."

4 Hydrocarbon liquids greater than or equal to 20°API are considered "light crude."

5 "Other" category includes instruments, loading arms, pressure relief valves, stuffing boxes, compressor seals, dump lever arms, and vents.

6 Hydrocarbon liquids less than 20°API are considered "heavy crude."

Table 1B

Default Average Component Counts for Major Onshore Natural Gas Production Equipment

*Major equipment*	*Valves*	*Connectors*	*Open-ended lines*	*Pressure relief valves*

Western U.S.
Wellheads	11	36	1	0
Separators	34	106	6	2
Meters/piping	14	51	1	1
Compressors	73	179	3	4
In-line heaters	14	65	2	1
Dehydrators	24	90	2	2

Table 1C

Default Average Component Counts for Major Crude Oil Production Equipment

*Major equipment*	*Valves*	*Flanges*	*Connectors*	*Open-ended lines*	*Other components*

Western U.S.
Wellhead	5	10	4	0	1
Separator	6	12	10	0	0
Heater-treater	8	12	20	0	0
Header	5	10	4	0	0

Table 2

Default Total Hydrocarbon Emission Factors for Onshore Natural Gas Processing

	Onshore natural gas processing	Emission factor (scf/hour/component)
Leaker Emission Factors -- Compressor Components, Gas Service
	Valve1	14.84
	Connector	5.59
	Open-Ended Line	17.27
	Pressure Relief Valve	39.66
	Meter	19.33

Leaker Emission Factors -- Non-Compressor Components, Gas Service
	Valve1	6.42
	Connector	5.71
	Open-Ended Line	11.27
	Pressure Relief Valve	2.01
	Meter	2.93

1 Valves include control valves, block valves and regulator valves.

Table 3

Default Total Hydrocarbon Emission factors for Onshore Natural Gas Transmission Compression

Onshore Natural Gas Transmission compression		Emission factor (scf/hour/component)
Leaker Emission Factors -- Compressor Components, Gas Service
	Valve1	14.84
	Connector	5.59
	Open-Ended Line	17.27
	Pressure Relief Valve	39.66
	Meter	19.33

Leaker Emission Factors -- Non-Compressor Components, Gas Service
	Valve1	6.42
	Connector	5.71
	Open-Ended Line	11.27
	Pressure Relief Valve	2.01
	Meter	2.93

Population Emission Factors -- Gas Service
	Low Continuous Bleed Pneumatic Device Vents2	1.37
	High Continuous Bleed Pneumatic Device Vents2	18.20
	Intermittent Bleed Pneumatic Device Vents2	2.35

1 Valves include control valves, block valves, and regulator valves.

2 Emission Factor is in units of "scf/hour/component."

Table 4

Default Total Hydrocarbon Emission Factors for Underground Natural Gas Storage

*Underground natural gas storage*		*Emission factor (scf/hour/component)*
Leaker Emission Factors -- Storage Station, Gas Service
	Valve1	14.84
	Connector	5.659
	Open-Ended Line	17.27
	Pressure Relief valve	39.66
	Meter	19.33

Population Emission Factors -- Storage Wellheads, Gas Service
	Connector	0.01
	Valve1	0.1
	Pressure Relief Valve	0.17
	Open Ended Line	0.03

Population Emission Factor -- Other Components, Gas Service
	Low Continuous Bleed Pneumatic Device Vents2	1.37
	High Continuous Bleed Pneumatic Device Vents2	18.20
	Intermittent Bleed Pneumatic Device Vents2	2.35

1 Valves include control valves, block valves and regulator valves.

2 Emission Factor is in units of "scf/hour/device.

Table 5

Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage

*LNG Storage*		*Emission factor (scf/hour/component)*

Leaker Emission Factors -- LNG storage Components, Gas and Liquids Service
	Valve	1.19
	Pump Seal	4.00
	Connector	0.34
	Other1	1.77

Population Emission Factors -- LNG Storage Compressor, Gas Service
	Vapor Recovery Compressor2	4.17

1 "other" equipment type should be applied for any equipment type other than connectors, pumps, or valves.

2 Emission Factor is in units of "scf/hour/compressor."

Table 6

Default Methane Emission Factors for LNG Import and Export Equipment

*LNG import and export equipment*		*Emission factor (scf/hour/component)*

Leaker Emission Factors -- LNG Terminals Components, Gas and Liquid Service
	Valve	1.19
	Pump Seal	4.00
	Connector	0.34
	Other1	1.77

Population Emission Factors -- LNG Terminal Compressor, Gas Service
	Vapor Recovery Compressor2	4.17

1 "other" equipment type should be applied for any equipment type other than connectors, pumps, or valves.

2 Emission Factor is in units of "scf/hour/compressor."

Table 7

Default Methane Emission Factors for Natural Gas Distribution

Natural gas distribution		Emission factor (scf/hour/component)

Leaker Emission Factors -- Above Grade M&R at City Gate Stations1 Components
	Connector	1.69
	Block Valve	0.557
	Control Valve	9.34
	Pressure Relief Valve	0.27
	Orifice Meter	0.212
	Regulator	0.772
	Open-ended Line	26.131

Population Emission Factors -- Below Grade M&R2 Components, Gas Service3
	Below Grade M&R Station, Inlet Pressure >300 psig	1.30
	Below Grade M&R Station, Inlet Pressure 100 to 300 psig	0.20
	Below Grade M&R Station, Inlet Pressure <100 psig	0.10

Natural gas distribution		Emission factor (scf/meter-hour)

Population Emission Factors -- Customer Meters
	Residential	0.01582
	Commercial	0.00547
	Industrial	0.00547

Natural gas distribution		Emission factor (scf/hour/component)

Population emission Factors -- Distribution Mains, Gas Service4
	Unprotected steel	12.58
	Protected Steel	0.35
	Plastic	1.13
	Cast Iron	27.25

Population Emission Factors -- Distribution Services, Gas Service5
	Unprotected Steel	0.19
	Protected Steel	0.02
	Plastic	0.001
	Copper	0.03

1 City gate stations at custody transfer and excluding customer meters.

2 Excluding customer meters.

3 Emission Factor is in units of "scf/hour/station."

4 Emission Factor is in units of "scf/hour/mile."

5 Emission factor is in units of "scf/hour/number of services."

1. New Appendix A filed 12-19-2012; operative 1-1-2013 pursuant to Government Code section 11343.4 (Register 2012, No. 51). For prior history of Appendix A, see Register 2011, No. 50.
2. Amendment of Appendix A, Table 7 filed 12-31-2014; operative 1-1-2015 pursuant to Government Code section 11343.4(b)(3) (Register 2015, No. 1).
3. Amendment of table 7 adding footnote reference filed 9-1-2017; operative 1-1-2018 (Register 2017, No. 35).

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