Proposal by the Southwest Clean Air Agency (SWCAA) for SIP Update of SWCAA 491

Background
The version of SWCAA 491 that is incorporated into the Washington SIP (dated November 21, 1996) requires Stage II vapor recovery as follows:

   SWCAA 491-040(5)(a) " This section shall apply to the refueling of motor vehicles for the general public from stationary tanks at all gasoline dispensing facilities located in Cowlitz, Lewis, and Wahkiakum Counties with an annual gasoline throughput greater than one million two hundred thousand gallons (1,200,000). For Clark County, this section shall apply to gasoline dispensing facilities with an annual gasoline throughput greater than six hundred thousand gallons (600,000); these facilities shall install Stage II controls by December 31, 1998 or at the time of a facility upgrade (see definition). Skamania County is exempt from Stage II requirements as provided in RCW 70.94.165.

The current version of SWCAA 491-040 (effective February 7, 2020) differs in a number of important ways:
 Stage II vapor recovery is not required for new installations.
 For stations with Stage II vapor recovery systems that are not compatible with onboard refueling vapor recovery (ORVR), the Stage II systems must either be removed or upgraded to be ORVR-compatible by January 1, 2023.
 All Stage I nozzles must be enhanced conventional nozzles no later than January 1, 2023.
 All gasoline dispensing hoses that carry liquid fuel against the outermost hose wall at a gasoline dispensing facility with greater than 1,400,000 gallons annual gasoline throughput on a calendar year basis shall permeate no more than 10.0 grams per square meter per day, as determined by Underwriters Laboratories' Standard 330, by no later than January 1, 2023.
 All stations with a gasoline throughput of more than 200,000 gallons per year in Clark County, or 360,000 gallons per year in Cowlitz, Lewis, Skamania or Wahkiakum Counties must conduct the following testing:
Test
Frequency
CARB Test Procedure 201.3 (TP-201.3) "Determination of 2 Inch w.c. Static Pressure Performance of Vapor Recovery Systems of Dispensing Facilities"
Annually
CARB Test Procedure 201.1B (TP-201.1B) "Static Torque of Rotatable Phase I Adaptors"
Annually
Depending on the system configuration, either Test Procedure 201.1C (TP-201.1C) "Leak Rate of Drop Tube/Drain Valve Assembly" or Test Procedure 201.1D (TP-201.1D) "Leak Rate of Drop Tube Overfill Prevention Devices and Spill Container Drain Valves."
Annually
CARB Test Procedure 201.1E (TP-201.1E) "Leak Rate and Cracking Pressure of Pressure/Vacuum Vent Valves" adopted October 8, 2003
Every 3 calendar years
      Previously, these tests were only required when incorporated into the facility's Air Discharge Permit.  Some grandfathered facilities were not subject to any testing.
      
With the increasing penetration of onboard refueling vapor recovery (ORVR) in the motor vehicle fleet, the control of refueling emissions by Stage II vapor recovery systems at the refueling facilities is becoming unnecessary for ORVR-compatible systems, and counter-productive for incompatible vacuum-style systems.  Leaving Stage II vapor recovery systems in place that are not compatible with vehicles equipped with ORVR will result in increased emissions ("incompatibility excess emissions") from those facilities.  These increases would eventually exceed the benefit of the Stage II vapor recovery program overall.  Balance-style Stage II vapor recovery systems and ORVR-compatible vacuum-assist Stage II vapor recovery systems, if operating properly, would provide a diminishing benefit as the ORVR fleet penetration increases.

Calculating Methodology
SWCAA calculated the impact of the removing Stage II vapor requirements consistent with EPA's August 7, 2012, guidance labeled "Guidance on Removing Stage II Gasoline Vapor Control Programs from State Implementation Plans and Assessing Comparable Measures."  

SWCAA calculated the impact of the new requirement to install enhanced conventional nozzles as follows:
 For each facility without Stage II vapor recovery, the total gasoline throughput in 2019 was multiplied by the difference in emission factors for conventional and enhanced conventional nozzles.  SWCAA used the following emission factors:
 A factor of 0.61 lb/1,000 gallons dispensed for conventional nozzles; and
 A factor of 0.24 lb/1,000 gallons dispensed for enhanced conventional nozzles.
 For each facility with Stage II vapor recovery, the total gasoline throughput in 2019 was multiplied by the difference in emission factors for Stage II and enhanced conventional nozzles.  SWCAA used the following emission factors:
 A factor of 0.42 lb/1,000 gallons dispensed for Stage II nozzles; and
 A factor of 0.24 lb/1,000 gallons dispensed for enhanced conventional nozzles.
      For any facility that choses to retain, or upgrade to, ORVR-compatible Stage II vapor recovery, the impact of the additional Stage II controls more than offsets the difference in the nozzle emission factors until more than 98.5% of the fuel is dispensed to ORVR vehicles.

SWCAA calculated the impact of the new requirement to install low permeation hoses as follows:
 For each facility without balance-style Stage II vapor recovery and a throughput of over 1,400,000 gallons or more per year, the total gasoline throughput in 2019 was multiplied by the difference in emission factors for normal and low permeation hoses.  SWCAA used the following emission factors:
 A factor of 0.062 lb/1,000 gallons dispensed for normal hoses; and
 A factor of 0.009 lb/1,000 gallons dispensed for low permeation hoses.
      Hose permeation from balance-style hoses is relatively small because these hoses do not carry fuel (only vapor) against the outermost hose.

The nozzle and hose emission factors cited above originate from a California Air Resources (CARB) document titled "Revised Emission Factors for Gasoline Marketing Operations at California Gasoline Dispensing Facilities" dated December 23, 2013.

Calculation of ORVR Fleet Penetration
The ORVR fleet penetration was estimated conservatively from 2020 Washington Department of Licensing data.  Because this data did not identify vehicles using the same "bins" as the ORVR phase-in schedule (e.g., LDVs, LLDTs, HLDTs, HDGVs, etc.), SWCAA made the following conservative assumptions:
 Only vehicles with a vehicle use classification of "PAS" or "CAB" were classified as passenger vehicles.  "PAS" refers to a passenger vehicle.  "CAB" refers to a taxi cab.
 If the vehicle use classification was not "PAS" or "CAB" and the vehicle weight was not provided, it was conservatively classified as a heavy truck.
 If the vehicle use classification was not "PAS" or "CAB" and the vehicle weight was equal to or greater than 5,750 lbs, the vehicle was classified as a heavy truck.
 If the vehicle use classifications was not "PAS" or "CAB" and the vehicle weight was less than 5,750 lbs, the vehicle was classified as a light truck.
 Vehicles did not contain ORVR systems until the model year required by the federal regulations.
The ORVR fleet penetration values resulting from this analysis were approximately four to eight years behind the estimated national average provided by EPA's National Canister Penetration Forecast based on MOVES 2010(a) for the counties impacted by the rule change.  If the actual penetration in these counties is closer to the national average, then the changes proposed to SWCAA 491 will provide an emissions benefit that much earlier than calculated.

Results
The results of the SWCAA's impact analysis are presented in the following table.  SWCAA's analysis demonstrates that the rule provides a benefit to air quality in all counties when fully implemented in 2023.

Rule Impact Summary  -  Impact in 2023
                                    County
                                 Incrementi[1]
           Annual Emissions Impact of Removing Stage II Requirements
                            (Increment) (Tonsi)[1]
                Impact of Low Permeation Hoses and ECO Nozzles 
                                    (Tons)
                           Total Rule Impact (Tons)
                                     Clark
                                     1.1%
                                     8.91
                                    -18.99
                                    -10.08
                                    Cowlitz
                                     2.1%
                                     5.63
                                     -7.48
                                     -1.85
                                     Lewis
                                     1.4%
                                     3.77
                                     -7.23
                                     -3.46
                                   Wahkiakum
                                     0.0%
                                     0.00
                                     -0.14
                                     -0.14
                                   Skamania
                                    N/A[2]
                                    N/A[2]
                                     -0.47
                                     -0.47
                                      All
                                       
                                     18.31
                                    -33.84
                                    -15.99
1 This is the amount by which the combination of the existing Stage II program combined with ORVR-equipped vehicles reduces VOC emissions when compared to the ORVR system alone.
[2] Stage II vapor recovery was not required in Skamania County and no gas stations currently utilize Stage II vapor recovery in Skamania County.

This analysis indicates that the rule change will reduce gasoline vapor emissions by 15.99 tons in 2023.  This emissions benefit will continue to increase in later years because, without the rule change, "incompatibility excess emissions" would have continued to increase as the percentage of ORVR-equipped vehicles increased.

Conclusions
The proposed changes to SWCAA 491 will provide a benefit to air quality when fully implement in 2023 and therefore will not interfere with maintenance of the National Ambient Air Quality Standards for ozone.

Calculation Details
The default values presented in "Guidance on Removing Stage II Gasoline Vapor Control Programs from State Implementation Plans and Assessing Comparable Measures" EPA-457/B-12-001 (August 7, 2012) were used except as indicated below:
 ηiuSII (Stage II vapor recovery system in-use control efficiency) = 62%.  SWCAA conducts inspections of gasoline stations on a 5-year schedule.  EPA's "Technical Guidance -- Stage II Vapor Recovery Systems for Control of Vehicle Refueling at Gasoline Dispensing Facilities Volume I: Chapters," (EPA - 450/3 - 91 - 022a, November 1991) indicates an in-use effectiveness of 62% for an inspection frequency that is less than annual.
 QSII (Fraction of highway gasoline throughput dispensed by Stage II vapor recovery systems).  SWCAA inventories the gasoline throughput of each dispensing facility each year and tracks what type of vapor recovery system (if any) is in use at each facility.  This value is from year-end 2019 data.  It was assumed that this value would also be representative of future years without a rule change.
 QSIIva (fraction of highway gasoline throughput dispensed through ORVR-incompatible Stage II vapor recovery systems).  SWCAA inventories the gasoline throughput of each dispensing facility each year and tracks what type of vapor recovery system (if any) is in use at each facility.  This value is from 2019 data and assumes that all vacuum-assist systems utilizing the Healy 800 or 900 nozzles are ORVR compatible.  For calculation purposes it was assumed that the 2019 ratio would also be representative of future years without a rule change.
 The ORVR vehicle population percentage for Clark and Cowlitz counties was determined for the end of 2020 from Washington Department of Motor Vehicles vehicle registration data.   This value was correlated to the national fleet values from Table A-1 to determine the correlating "VMT Percentage" and "Gasoline Dispensed Percentage."  The data as conservatively processed, indicates that the vehicle fleets in SWCAA's jurisdiction are older than the national average indicated in Table A-1 with respect to canister penetration.   The "Gasoline Dispensed Percentage" for each year in each county was calculated by interpolating from Table A-1 using the year matching the fleet canister penetration percentage.  For example, the "VMT Percentage" for 2020 in Clark County was determined by interpolating between the 2015 and 2016 values in Table A-1.

Attachments

 "Vancouver Portion of the Portland-Vancouver AQMA Ozone Maintenance Plan" November 2, 2006
 "Guidance on Removing Stage II Gasoline Vapor Control Programs from State Implementation Plans and Assessing Comparable Measures" EPA-457/B-12-001.  August 7, 2012
 SWCAA 491 "Emission Standards and Controls for Sources Emitting Gasoline Vapors" (local only version) February 27, 2021.
 SWCAA 491 "Emission Standards and Controls for Sources Emitting Gasoline Vapors" (SIP Approved Version) November 21, 1996.
 CARB "Revised Emission Factors for Gasoline Marketing Operations at California Gasoline Dispensing Facilities" December 23, 2013.
   
				
