AST Stakeholder Meeting

1. AST Stakeholder Meeting California Air Resources Board Stakeholder Meeting February 17, 2005 1927 13th Street, Room 202 10:00 a.m. - 12:00 p.m.

2. AST Stakeholder Meeting Agenda • Welcome and Introductions • Overview of AP-42 emission estimation approach • Discuss the comments received by stakeholders • Results from small scale studies • Future Plans • Contact Information

3. AST Stakeholder Meeting Welcome and Introductions

4. AST Stakeholder Meeting Overview of AP-42 Emission Estimation Approach

5. AP-42 Emission Estimation Approach • Purpose: • Use AP-42 approach to calculate statewide emission estimate for Aboveground Storage Tanks (ASTs)

6. AP-42 Emission Estimation Approach • Statewide Emission Estimate For ASTs: • Sum of emissions calculated for 16 regions in CA. • Emissions from each region are calculated based on the tank size and configuration. Emissions = Tank Population x Emission Factor

7. AP-42 Emission Estimation Approach • Tank Population: • Number of tanks in a region by size, type, and vapor recovery configuration. • Determined from a statewide survey of fuel haulers.

8. AP-42 Emission Estimation Approach • Survey Status: • Contacted 187 companies • 62 companies responded • Extrapolated results determined the presence of approximately 9,300 tanks statewide • Survey portion is completed

9. AP-42 Emission Estimation Approach • Emission Factor: • It is an estimated amount of hydrocarbon emissions emitted into the atmosphere in a given period of time. • Calculated on a monthly basis.

10. AP-42 Emission Estimation Approach • AP-42 Methodology: • Developed by American Petroleum Institute (API) • Is approved by the U.S. EPA • Widely used by industry • Calculates Total losses/emissions from ASTs Emissions = Standing Storage or Breathing Loss + Working Loss • Applies only to tanks vented through small orifices or pressure relief valves.

11. AP-42 Emission Estimation Approach • Standing Storage or Breathing Loss (Ls) • It is a loss due to evaporation. Heating of the tank by the sun causes the fuel to volatilize and vent to the atmosphere. LS = nVVWVKEKS • Please review pages 2 - 5 of the AP-42 document

12. AP-42 Emission Estimation Approach • Working Loss (Lw) : • This loss occurs when mass of vapors are emitted to the atmosphere during the: • Transfer of gasoline from cargo tank to AST (Deliveries) • Transfer of gasoline from AST to vehicle (Dispenses) Lw = Lw(Deliveries) + Lw(Dispenses) • Please review pages 6 and 7 of the AP-42 document.

13. AP-42 Emission Estimation Approach • Sacramento Case Study • Used AP-42 methodology to calculate emission factors for 751 - 1000 gallon tank with various configurations. • Intend to apply this calculation methodology to different tank sizes and configurations for all 16 regions in California. • Methodology uses reasonable assumptions.

14. AP-42 Emission Estimation Approach • Assumptions Used: • Tank is half full on average. • Fuel surface temperature range is derived from the ambient temperature range. • Phase I or Phase II vapor recovery controls • Tanks with controls have a P/V valve at 2” WC • Tanks without controls have no P/V valve • Working loss emissions assumes 2 deliveries per year and 95% control for both Phase I and Phase II vapor recovery systems.

15. AP-42 Emission Estimation Approach

16. Comments Received • Approach seems reasonable. • Deliveries for some styles of tanks may be greater than two per year. • Assumption of no P/V valves for tanks with no Phase I or Phase II controls needs to be investigated. • Additional comments?

17. Small Scale Studies(AP-42 Bias) • How well does AP-42 predict actual emissions from open tanks? • Web search found two AST studies that measured emissions from open tanks without pressure relief valves. • ARB performed some initial observations on small one gallon tanks with various vent openings.

18. Small Scale Studies(Published Literature) AP-42 Versus Volumetric Loss (Summer Monthly Loss for a 1200 L Tank, No Pressure Relief Valve)

19. Small Scale Study(ARB Initial Observations) AP-42 Versus Gravimetric Measurement (16 Degree F Temperature Increase)

20. Small Scale Study • Conclusions: • AP-42 method significantly under estimates emissions on open systems without pressure relief valves. • Need to refine method to measure emissions from open systems.

21. Future Plans • AP-42 Correlation Study on 50 gallon AST • Control Technology Demonstration Using Two Identical 50 gallon ASTs • One AST will serve as a control. • Second AST will be retrofitted with control technology. • Emission reductions will be incrementally measured with a carbon canister.

22. Need Volunteers • We need volunteers to give us access to their full size AST, so further correlation studies can be done.

23. Contact Information General AST Information • Joe Guerrero (916) 324-9487 - jguerrer@arb.ca.govStephanie Connelly (916) 445-9308 - saconnel@arb.ca.gov Tank Population • Ranjit Bhullar (916) 322-0223 - rbhullar@arb.ca.govLaMar Mitchell (916) 445-9371 - lmitchel@arb.ca.gov Emission Inventory • Jim Watson (916) 327-1282 - jwatson@arb.ca.gov • Pamela Gupta (916) 324-4458 - pgupta@arb.ca.gov

24. Contact Information Need More Information? • ARB Vapor Recovery Website: • www.arb.ca.gov/vapor/vapor.htm • ARB Aboveground Storage Tank Website: • www.arb.ca.gov/vapor/ast/ast.htm