NATIONAL INSTITUTE OF AEROSPACE TECHNOLOGY

1. NATIONAL INSTITUTE OF AEROSPACE TECHNOLOGY OPTIMIZATION OF A SOLAR HYDROGEN STORAGE SYSTEM: SAFETY CONSIDERATIONS Rosa Mª Rengel Gálvez Marina B. Gutiérrez García-Arias 11/09/2007

2. NATIONAL INSTITUTE OF AEROSPACE TECHNOLOGY • Public organization for aerospace technology research and development. • Since the early seventies, renewable and alternative energies have been one of the R&D areas in which INTA has dedicated a continuous effort. • In 1989, INTA started a program focussed on the use of hydrogen as a storage medium for solar electricity. • Since 1990, interest in terrestrial use of fuel cells and hydrogen technologies. • Facilities in Torrejón de Ardoz (Madrid) and “El Arenosillo” (Huelva).

3. Development of Metal Hydride H2 Storage Systems Fuel Cell vehicle 12 kW PEMFC Test Bench AREAS OF INTEREST Hydrogen production from renewable energy, mainly solar and wind.- Development of new hydrogen storage systems.- PEMFC testing. - Integration of PEMFC in transport applications.- Development of hydrogen production systems from fossil or renewable fuels.- Simulation of hydrogen systems (energy and CFD aspects) .- Safety.

4. INTA SOLAR HYDROGENSTORAGE FACILITY • Built up in the period 1992-1996. • Original design: passive and active safety measures → legislation and good engineering practices , but not a specific risk assessment was done: • ATEX • Pressure vessel regulations. • Operational period: additional safety recommendations from international standards → • ISO/TR 15916 Basic consideration for the safety of hydrogen system

6. STORAGE FACILITY CHARACTERISTICS • Hydrogen production rate: 1.2 Nm3/h • Hydrogen storage capacity: enough for an operation week (25-30 Nm3) • Operation during 48 weeks per year • Charging cycles number higher than discharging cycles number • Availability and reasonable cost for small facilities • Other requirements: availability, auxiliary systems, etc.

7. H2 production from renewable energy needs H2 storage systems Safety requirements RISK ASSESSMENT A risk can be defined as “a measure of a significance of hazard involving simultaneous examination of its consequences and probability of occurrence for the scenario”. RISK ASSESSMENT

8. Hazard identification is the most important step in risk analysis QUANTITATIVE RISK ASSESSMENT (QRA)

9. HAZARD IDENTIFICATION The objective is to determine a list of potential incidents might be occurred to the accidents. WHAT CAN GO WRONG? • METHODS: • FMEA • HAZOP • What-if analysis • Check list analysis • Fault tree analysis • Event tree analysis BEFORE THE PROJECT IS FULLY IMPLEMENTED OR A REDESIGN OF A PLANT

10. FMEA • Qualitative method. • FMEA: systematic methodology to identify product and process problems, assessing their significance, and identifying potential solutions that reduce their significance. • Each failure mode has a cause and a potential effect. • Can be performed by two different approaches: bottoms-up / top down.

11. METHODOLOGY • FMEA to the three different solar hydrogen storage systems => failure modes, causes and effects. • FMEA is an ongoing process and must be updated every time design or process changes are made => Top-down approach. • For a good quality hazard identification, complete information about the system must be compiled. • The data was provided to a team with expertise on various aspects of hydrogen.

12. FMEA Results for each hydrogen storage section

15. CONCLUSIONS • Main potential failure modes: • container or cylinders failure, • piping leaks and valves fails, originated by mechanical or material failure, corrosion or hydrogen embrittlement, • human error. • The results of the study have helped to identify a design inherent safety for the new facility, and identify potential prevention and/or mitigation corrective actions. • Suitable choice of materials and the need of training of personnel are essential for safety purposes.

16. Thanks for your attention. rengelgrm@inta.es gutierrezgamb@inta.es