UNITED S T ATES ENVIRONMENTAL PROTECTION AGEN C Y

NATIONAL VE H I C L E AND F UEL E M I SSIONS LABORATORY

2565 P LYM O U T H ROAD

ANN ARBO R

, MICHIGAN 48105

- 2498



### MEMORANDUM Sep t em b er 24, 2012 O F F I CE

OF

A IR A ND

RADIATION

SUBJECT: Calculation of Emiss i ons from GDFs

FROM: Glen n W

. Passavan t

, Office of Trans p ort a tio n an d Ai r Quality



### TO: Public Docket EP A

- H Q

- OA R

- 2 0 1 1

- 0151

A. Introduction:

T h i s memo addresses technical a n d e m iss i on aspects of how the emission and

throughput va l ues in Table 3 o f the proposed rule (Ge n eral P e r mi ts and Permits

by R u l e f o r the Trib a l Minor N e w Source Review Program) were calculated. The

ta b le i s c o p ied bel ow for ease o f r eference:

Table 3

. Emissions from Gasol i ne Dispensing Facilities with ORVR Consideration

NSR

CATEGORY End of

Calendar

Year %

ORVR Di s p

.

l b / 1 000

g a l Breathing

Losses

lb/1000

gal Stage I

lb/1000

. gal Total

lb/1000

gal Gallons per

year (gpy)

Equivalent Gallons

per month

( gpm )

Equivalent

1a 2

tpy Ozone

NA 2011 72% 2

. 1 0.25 0.3 2

. 65 1,509,434 125,786

1b 2

tpy Ozone

NA 2014 82% 1. 3 5 0.25 0

. 3 1.9 2,10 5

, 263 175,439

1c 2

tpy Ozone

NA 2020 92% 0. 6 0 0.25 0.3 1

. 1 5 3,478,261 289,855

1d 2

tpy Ozone

NA 2025 96% 0.3 0.25 0.3 0

. 85 4,705,882 392,157

2a 5

tpy Ozone

attain 2011 72% 3

. 02 0.25 0.3 3.57 2,801,112 233,427

2b 5

tpy Ozone

attain 2014 82% 1. 9 4 0.25 0.3 2.49 4

. 0 1 6,064 334,673

2c 5

tpy Ozone

attain 2020 92% 0. 86 0.25 0.3 1.41 7,142,857 595,238

2d 5

tpy Ozone

attain 2025 96% 0. 4 3 0.25 0.3 0

. 98 10,20 4

, 082 850,340Gasoline vapor emissions from op e r ations at GDFs aris e from four major categories no rm ally

identified as occurring either i n Stage I or Stage II operations at the GDF. Stage I involves

transfer of gasoline from t h e tanker tr uck to the storage tank while Stage II involves transfer

of gasoline from the stora g e tank to the vehicle/equipment. EPA's emission factors document

AP

- 42 contains background information on these sources and some info rm ation on

emission rates

. 1

B. Discussion

Stage I GDF emissions are those v e n ted from the storage tank when gasoline is off

- loaded

from the tanker truck. As indicat e d in A P

- 42, if uncontrolled these emissions can be quite

large (1 1

. 5 lb/ 1 000 gal). However, v apor balance submerged filling technology reduces these

e m i ssions by over 95 percent and t h i s control technology is commonly required. The 0.3

lb/1000 gal emission rate listed ab o v e includes implementation of vapor balance submerged

filling technology.

Stage II refueling emissions from GDFs are comprised of three different segments including

vapor displacement from the vehic l e gasoline tank, gasoline spillage during refueling related to

sy s t em design and by the person h a n dling the nozzle, and breathing losses related to the

storage tank drawing in fresh air after refueling events and as a result of diurnal changes in

atmospheric pressure and temperat u r e

. Most breathing loss emissions occur during extended

periods of very low or no dispenser activity such as in the late evening and overnight hour s

.

Displacement emissions are a fun c t i on of the gasoline Reid vapor pressure (RVP), the

temperature of the dispensed gasol i n e, and the temperature of the fuel in the vehicle's gasoline

tank. A P

- 42 estimates a national a v erage annual value of about 11 lbs VOC/ per 1000 gallons

of gasoline dispensed, but t h i s value is substantially lower in states with vapor pressure control.

In this analysis, displacement losses are being modeled using 7 RVP for ozone no n

- attainment

areas with dispensed a n d tank fuel temperatures representative of the summer time western US

and 10 RVP gasoline f o r ozone attainment areas with dispensed and tank fuel

temperatures representative of the s u mmertime US national average

. 3 The emission rate was then reduced

by applying the onboard refueling vapor recovery (ORVR) control technology required by section

202(a)(6) of the Clean Air Act. Other analyses conducted by EPA show that ORVR is 98 percent

effi c ient a n d that the percentage of gasoline dispensed to ORVR equipped vehicles will increase ov e r time

as ORV R

- equipped vehicles replace those without ORV R

. 4

' 5

AP

- 42 estimates breathing losses to average about 1 lb VOC /1000 gallons of fuel dispense d

. Under the requirements of 40CFR 6 3 CCCCCC, most GDFs have installed pressure/vacuum

valves on storage tank vent pipes w h ich suppress air inflow and vapor outflow. Test data

available to EPA indicates that the s e p/v valves are at 50

- 7 5 percent efficient. The

uncontrolled emission r ate measur e d in the referenced study was less than ten percent of the

value cited in AP

- 42, so the higher e nd of the efficiency range was used here, yielding an

emission rate of about 0.25 lb VOC /1000 gallon dispensed

. 6

1 US EP A

, A P

- 4 2

, C ompi lation of Air Pollutant Emiss i o n Factors, Volume I

, Fifth Edition, Chapter S.

2 The equation for calculating the em i s s i on rate was tak e n from the 1988 CRC report prepared by ATL entitle d

, A Study of U n c ontrolled

Automotive Refueling Emissions. This report is availa ble e in public docket A

- 87

- 1 1

. The emission rate in g/gal

= exp [

- 1.2798

-

.0049(L'

- T)+.0203(Td)+0.1315(RVP) ]

.

3 See EPA report, Refueling Emissions from Uncontrolled V ehicles, EPA

- AA

- SDS B

- 85

- 6, 1985. This report is av a i l able in public docket A

- 8 7

- 11.

4 See EPA Memorandum, Updated OR V R I n

- Use Effi c i e n c y

, Glenn W. Passavant, EPA Office of Transportation and Air Quality, February 7

, 2012.

This is available at EPA public docket EPA

- HQ

- OA R

- 20 1 0

- 1076.

5 See EPA Memorandum, Updated ORVR Widespread Use Assessment, Glenn W

. Passavant, EPA Office of Transportation and Air Qualit y

, February

29 , 2012

. This is available at EPA public docket EPA

- H Q

- OAR

- 2010

- 1076.

6 Und e r ground Storage Tank Vent Line Emissions from R e t ail Gasoline Outlets, Western States Petroleum Association

, project FR

- 92

- 01

- 204R2, May,

I 994. This is available at EPA public docket EPA

- H Q

- OAR

- 2 0 10

- 1076. 

### 2The three emission rates in lb VO C / 1 000 gallons dispensed are then su m med to get a total

r a t e for the GDF. These were then c o nverted to tons VOC/ 1 000 gal and divided into the 2 ton/

year and 5 ton/year threshold values t o get the annual v a l ue or further divided by 12 to get the

monthly values as shown above

Gasoline spillage is a source of e m i ssions in the refueling event, but could be considered a

fugitive emission for NSR purposes under cu rr ent EPA regulations and thus would not be part of

the overall inventory calculatio n

. Early studies of gasoline spillage during refueling indicate d

that spillage was about 0

. 7lb VOC/1000 gallons of fuel dispensed. Of this amount, about on e

half was related to either i ncompatibility between the vehicle fill pipe design and the dispensing

rate and the other half was related to the design of the nozzle and the effects of handling of the

nozzle as it was re m o ved from and replaced in the dispenser

. 7 EPA regulatory actions in the

1990's reduced spillage i n

- use through emission standards and test procedures which encouraged

compatibility b e t w een fill pipe designs, nozzle geometries, and dispensing rates and EPA also

limited dispen s i ng rates in

- use

. 8 EPA estimates that these actions have reduced spillage

emission rates by a b out 50 percent relative to the values in AP

- 42 or about 0.35 lb/1000 gal. 9 If

spillage was i ncluded, the gpy and gpm v a l ues would be proportionally lower. For example, in

2014 the oz o n e nonattainment values would be calculated by dividing the 2 tons/yr (4000 lb/yr)

value by 2

. 25 lb/ 1 000 gal instead of the value shown in Table 5, column 9 ( 1

. 9 lb/ 1 000 gal).

7 In v e s t i gatio n of Passenger C a r Refueling L o s se s : Malc o lm m Smit h

, S cott Research Laborator i e s

, Society of Automotive Engineers, Paper

720931

. T his is available at EPA public docket EPA

- HQ

- O A R

- 2010

- 1076.

8 See EPA regulatory requirements for in

- use dispensing rate limits (61 FR 33034, June 26, 1996) and the fuel dispensing spit back standard (58 FR

16021, March 24

, 1993) and ORVR test procedures which require that any fuel spilled in the SHED be counted in the 0.20 g/gal amount allowed for by

the emission standard under 40 CFR 86 Subpart B.

9 US EPA report: Development of Evaporative Emissions C a lculations for the Motor Vehicle Emissions Simulator MOVES 20 I 0, EP A

- 42 0

- R

- 12

- 027,

September 2012. 

### 3