Risk-Informed Process and Tools for Permitting Hydrogen Fueling Stations

1. Risk-Informed Process and Tools for Permitting Hydrogen Fueling Stations Jeffrey LaChance1, Andrei Tchouvelev2, and Jim Ohi3 1Sandia National Laboratories 2AVT & Associates 3National Renewable Energy Laboratory Presented at the 2nd International Conference on Hydrogen Safety San Sebastian, Spain 13 September 2007

2. This presentation describes an approach for risk-informing the permitting process for hydrogen fuelling stations that relies primarily on the establishment of risk-informed codes and standards. Risk-informed permitting processes exist in some countries and are being developed in others. To facilitate consistent risk-informed approaches, the participants in the International Energy Agency (IEA) Task 19 on hydrogen safety are working to identify acceptable risk criteria, QRA models, and supporting data. IEA Task 19 - Hydrogen Safety, is a collaboration of experts from eight countries, under the Hydrogen Implementing Agreement of the International Energy Agency (IEA) which operates under an international agreement of more than 26 countries. The overall goal of the IEA Task 19 is to develop data and other information that will facilitate the accelerated adoption of hydrogen systems and supports the accomplishment of the Hydrogen Implementing Agreement’s stated mission: “…to accelerate hydrogen implementation and widespread utilization.” Because of the nature of the International Energy Agency as an international agreement between governments, it is hoped that such collaboration will complement other efforts to build the technology base around which codes and standards can be developed. Preamble

3. Permitting Process Risk-Informed Framework for Permitting Risk Acceptance Criteria Risk-Informed Hydrogen Codes and Standards Risk Assessment Tools to Support Process Summary Outline

4. Purpose is to demonstrate that facility meets established safety requirements Many permitting authorities rely on compliance with codes and standards Current codes and standards specify safety features, material requirements, separation distances, operational requirements, risk management plans, etc. Compliance with codes and standards is accepted as evidence of a safe design Permitting Process

5. Challenge is to have a permitting process that is relatively simple and cost-effective but ensures a safe design Deterministic approach can introduce unnecessary conservatism Higher cost and restrictive siting Risk-based approach involves uncertainty that must be addressed Lack of data, model limitations, and unknown phenomena A risk-informed process combines risk information, deterministic analyses, and other considerations to make decisions Can include defense-in-depth and safety margins in design to address uncertainties Risk-Informed Approach for Permitting Hydrogen Facilities

6. Risk-Informed Framework for Permitting Hydrogen Facilities Design meets codes & standards? Develop risk-informed codes and standards Facility accepted by authorities Design hydrogen facility Yes No Perform risk-informed exemption evaluation Modify facility design QRA methods, data, & risk criteria Risk acceptable? Yes No

7. Risk Acceptance Criteria • Types • Individual risk – probability that an average unprotected person, permanently located at a certain location, is harmed due to an accident • Societal risk – probability that multiple people within an area are harmed due to an accident (typically represented on an FN curve) • Risk criteria can be specified for: • People living and working nearby • Users of the facility • Workers

8. Options for selecting risk criteria: Based on statistics from existing stations (gasoline and CNG) limited data available NFPA data for gasoline stations in U.S. suggests frequency of deaths and injuries per station are ~1x10-5/yr and ~3x10-4/yr, respectively Based on estimated risk for existing stations limited analyses are available differences in facilities and behavior affects comparison of data Comparing with general risk in society – hydrogen should not increase the general risk level in society Risk of fatality ~ 1 to 4x10-4/yr Risk Acceptance Criteria

9. Codes and standards applicable to hydrogen facilities are developed by a variety of code and standard development organizations (CDOs & SDOs) Basis for some current codes and standards are not well documented but generally utilized expert judgment, good engineering practices, and historical precedents Several CDOs are working to modify hydrogen codes Includes reestablishing the bases for code requirements including separation distances Several groups have been established to coordinate the development and implementation of a consistent set of hydrogen-related codes and standards Common theme of CDOs, SDOs, and industry groups is establishment of science-based requirements that will ensure a minimum level of safety Hydrogen Codes and Standards

10. Use of risk-informed process is one way to establish the requirements necessary to ensure a minimum level of safety Comprehensive QRA used to identify and quantify scenarios leading to hydrogen release and ignition or detonation Possible prevention and mitigation features and separation distances identified based on QRA Results combined with other considerations to establish minimum code and standard requirements needed for an established risk level Prevention and mitigation features and separation distances can be specified as a function of important facility parameters: Hydrogen generation method Volume and pressure of hydrogen Location of components (e.g., inside versus outside) Risk-Informed Codes and Standards

11. Several groups are developing tool kits to facilitate the permitting of hydrogen fueling stations: U.S. Department of Energy – addressed in previous paper Canadian Hydrogen Safety Program – paper 1.5.100 (includes QRA tool) HySafe initiatives including Hydrogen Incident Accident Database (HIAD) and HyQRA Tools for Supporting the Permitting Process

12. Development of comprehensive QRA models are required to support development of codes and standards QRA toolkit can also be used to: Help facility designers in complying with codes and standards, developing mitigation strategies, provide a basis for exemptions to requirements Educate authorities on possible hydrogen accidents and consequences Important features of QRA toolkit include: Simple but realistic consequence models for all possible accidents Accident sequence event trees Fault trees for accident initiators and mitigation system failure events Accepted data values for frequency of accidents, failure of mitigating equipment, and phenomenological events Propagation of parameter uncertainty and performance of sensitivity studies to address assumptions and model uncertainty Choice of risk criteria for establishing adequacy of a design Risk Assessment Tools for Supporting the Permitting Process

13. Risk-informed methods can be used to provide the basis for identifying minimum hydrogen code and standard requirements Requires establishing risk criteria for determining minimum code and standard requirements Compliance with the resulting codes and standards ensures a minimum level of safety When compliance is not possible, QRA can help provide a basis for an exemption Identification of acceptable QRA tool data and models is needed to support these efforts IEA Task 19 Hydrogen Safety group is striving to establish acceptable QRA models and data and the risk acceptance criteria Summary

14. The authors would like to thank: The U.S. Department of Energy and Natural Resources Canada for their contributions to funding this work Bill Hoagland, the Operating Agent of IEA Task 19 Hydrogen Safety for his contribution to this paper Acknowledgements