Improved Plant Safety Through Low Hydrogen Inventory Robert Friedland President and Chief Operating Officer April 2008

2 Acknowledgements John Speranza – Vice President of Sales Tom Skoczylas – Director of Applications Engineering Larry Moulthrop – Vice President, Hydrogen Systems

3 Topics of Discussion Why Hydrogen is used at power plants Modes of Hydrogen Supply Energy contained in hydrogen Possible modes of accidental release Example Leak Scenario Siting Considerations Real Incident Summary

4 HOGEN S-Series 0.5 to 1.0 Nm 3 /hr H 2 H 2 Pressure: 13 bar (200 psig) UHP H 2 ; % 97 x 79 x 106 cm; 215 kg Industrial, meteorological, fuel HOGEN H-Series 2-6 Nm 3 /hr H 2 ; 5-12 kg H 2 /day H 2 Pressure: 15 and 30 bar (435 psi) UHP H 2 ; % 200 x 80 x 200 cm; kg Option-rich, flexible design Power plants, heat treating Commercial Products – HOGEN ® H2 Generators HOGEN GC 300 or 600 cc/min Pressure to 13 bar % purity 23 x 37x 52 cm, 23 kg Analytical labs

5 Commercial Hydrogen: Power Plants StableFlow TM StableFlow Hydrogen Control System –Monitors power generator hydrogen: Purity Pressure Dew Point –Optimizes to OEM specifications –One StableFlow system required per power generator

6 Why Hydrogen is used to cool generators A Majority of the Electric Power Generated is with Hydrogen Cooled Generators. –Over 70% of generators >60MW worldwide Hydrogen is a more efficient cooling medium than air in contact with the windings because of its superior thermal conductivity (nearly 7X air) and low density (1/14 air) which reduces windage losses. A Hydrogen Cooled Generator cannot operate without hydrogen supply.

7 Modes of Hydrogen Supply Bulk Delivery –HP Cylinders –HP Tube Trailers –Liquid On Site Hydrogen Generation –Water Electrolysis

8 Siting Considerations NFPA 55 requires bulk storage greater than 15,000 scf to: –Be located outdoors or in a dedicated, ventilated and non combustible detached building. –Be at least 50 feet from public assembly areas, electrical areas and air intakes. –Be designated a classified area, limited in use and requiring special permitting. HOGEN ® Hydrogen generators –Can be installed indoors in non hazardous areas –Require no special permits

9 Chemical Energy Bulk Supply – 2500 psi typical (8.5 scf = 1lb TNT) –Common Tube Trailer = 50,000 scf H2 = 123 gal gasoline = 5585 lbs TNT –Fixed HP Tubes: 5,500 scf/tube = 13.5 gal gasoline = 644 lbs TNT –12 pack of Portable Cylinders = 3,600 scf H2 = 420 lbs TNT On-Site Hydrogen Generator – 200 psi typical –1.5 scf H2 = gal gasoline = 0.17 lbs TNT – ‘Insignificant’ Hydrogen, when ignited, burns 10 times faster than gasoline vapors

10 Possible Modes of Uncontrolled Hydrogen Release or Flow The gas and power industries have handled hydrogen for many years and know how to do so safely but constant hazards are evident –Make and Break Connections: Tube Trailer: Common every weeks Cylinder packs: every 4 -7 days service to one generator Hydrogen Generator: Rarely, –bulk delivery for plant re-gas of equipment maintenance typically once per year or eliminated totally if hydrogen generator is used to refill a tank for purpose of back up and re-gas operations. –Gas handling equipment failure: Pressure Relief Devices Pressure Regulators Excess Flow Check Valves Piping

11 Example: Leak Failure Scenario - Bulk Rapid release of hydrogen due to improper refill connection or equipment failure (or a moderate release if into a sheltered or covered area – inhibiting diffusion) Ignition source present before hydrogen diffuses and dilutes –Auto Ignition – Unlikely, 1085˚F (585˚C) –Ignition Energy only 1.9 x10 -8 BTU (0.02 mJ) Invisible Spark similar to a static discharge from a human body in dry conditions is a sufficient and likely cause for ignition

12 Example: Leak Failure – On-Site Generation Unintentional release due to pipe rupture, connector failure, or operator error Maximum leak rate possible = generation capacity of machine <4 scfm Would take 24 hrs to leak the equivalent of a common storage tube (5500 scf) or 9 days for a tube trailer equivalent (50,000 scf) Combustible mixture localized near the leak Unlikely to have accumulation of bulk storage equivalent unless improperly installed into a non ventilated confined space

13 Hydrogen Incident at Power Plant

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15 Incident Database Power Plant Hydrogen Incidents from –Hydrogen Explosion at Coal-Fired Power Plant (2007)Hydrogen Explosion at Coal-Fired Power Plant –Hydrogen Explosion Due to Inadequate Maintenance (2002)Hydrogen Explosion Due to Inadequate Maintenance –Hydrogen Leak in Auxiliary Building (1987)Hydrogen Leak in Auxiliary Building H2Incidents is intended for public use. It was built and is maintained by Pacific Northwest National Laboratory with funding from the U.S. Department of Energy.Pacific Northwest National LaboratoryU.S. Department of Energy

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17 Summary Bulk Supply: –Delivery – up to weekly –Volume per system: up to 50,000 scf common –Hazard – Significant risk to Life and Property Hydrogen Generator Supply –Connections are fixed –Volume is insignificant –Hazard – Insignificant risk to Life and Property

18 Thank You!