1. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Round Robin Testing of Commercial Hydrogen Sensor Performance – Observations and Results NHA Hydrogen Conference & Expo Long Beach CA W. Buttner, R. Burgess, C. Rivkin, M. Post, L. Brett, G. Black, F. Harskamp, P. Moretti May 3 rd – 6 th, 2010 Innovation for Our Energy Future

2. Sensors Uses are Well Established –Used Every Day –Safety Alerting –Equipment Maintenance –Seamless and Unnoticed –Integral part of modern life Common Uses: –Smoke/CO Detectors –Oxygen Sensors (cars) –Impact Sensors (airbags) –Infrared (remote control) –Motion (stoplights) 2

3. Innovation for Our Energy Future Sensors for the Safe Use of Hydrogen Hydrogen chemical safety sensors will be a critical aspect to safe hydrogen use in the future: –Sensors will alarm when unsafe conditions are present –Automatic shutdown can be initiated by sensors –Hydrogen Codes & Standards will require the use of sensors NFPA 52 – Vehicular Gaseous Fuel Systems Code (9.2.3.1) NFPA 55 – Compressed Gases and Cryogenic Fluids Code (7.9.3.2.1) 3

4. Innovation for Our Energy Future Sensors - Sensing Element vs. Detectors Sensing Element: A small device that as the result of a chemical interaction or process between the analyte gas and the sensor device transforms chemical or biochemical information of a quantitative or qualitative type into an analytically useful (electronic) signal. Detector: Comprised of sensing element and control electronics to generate a response (signal) that is directly related to concentration of the target analyte. From ISO 26142: Assembly with an integrated or a remote hydrogen sensor that is intended to detect and measure the hydrogen volume fraction over a declared measuring range. 4

5. Innovation for Our Energy Future Hydrogen Sensors Hydrogen Sensor Types (Sensing elements) Catalytic Bead (Pellistor) Electrochemical Metal Oxide (MOX) Metal Semiconductor (MOSFET) Optical Palladium Thin Film Surface Acoustic Wave (SAW) Thermal Conductivity Signal can be impacted (sensing element and detector) Hydrogen Environmental effects (T, P, RH) Chemical effects (interferences, poisons) Physical Parameters (age, mechanical stresses) Human factors (deployment parameters) 5

6. Innovation for Our Energy Future Sensor Performance Specifications 6 DOE Hydrogen Sensor Targets –Multi-Year Research, Development & Demonstration Plan –Measurement Range: 0.1% to 10% –Operating Temperature: -30°C to 80°C –Response Time: Faster than One Second –Accuracy: 5% of Full Scale –Gas Environment: Ambient Air, 10% to 98% Relative Humidity –Lifetime: 10 Years –Interference Resistant (e.g., Hydrocarbons) International Standards (ISO 26142) Hydrogen detection apparatus -- Stationary applications National Standards (UL2075) Standard for Safety Gas and Vapor Detectors and Sensors

7. Innovation for Our Energy Future JRC Hydrogen Sensor Test Facility Test sensors under precisely controlled and monitored conditions –Gas Parameters Flow rate (25 to 1000 sccm) Composition –Environmental Parameters Temperature (-40 to +130°C) Pressure (100Pa to 250kPa) Moisture (10 to 100% RH) –Accommodates multiple sensors –System control Attended operation Manually run and monitored –Extensive Sensor Testing IJHE 33 (2008) 7648-7657 IJHE 34 (2009) 562-571 7

8. Innovation for Our Energy Future NREL Safety Sensor Test Laboratory Test sensors under precisely controlled and monitored conditions –Gas Parameters Flow rate (25 to 1000 sccm) Composition –Environmental Parameters Temperature (-25 to +80°C) Pressure (subambient to 1.4 Bar) Moisture (<5 to 95% RH) –All common electronic interfaces –Accommodates multiple sensors –Fully automated control Around-the-clock operation Remotely run and monitored –Sensor Testing since 2008 New Fixture Commissioned 2009 8

9. Innovation for Our Energy Future Comparison of Facilities – similar but not identical Sensor chamber NREL: 4 Liter; 1L/min standard flow JRC: 2.4 L; 0.35 to 1 L/min standard flow Logging Profile NREL: Fixed Rate JRC: Variable (fast during change) Step Duration NREL: Sensor Steady-State JRC: Sensor Steady-State 9 Environmental Control Unique T, P, moisture control and monitoring systems Different suppliers of gas standards Operational NREL: Automated, remotely accessible, unattended around-the-clock JRC: Automated with manual control, restricted operational time Personnel

10. Innovation for Our Energy Future Manufacturers and Stakeholders Benefits: –Unbiased platform to test technology –test data and analytical feedback is provided –Specific test data results is kept confidential –General data will be compiled and made available to stakeholders –“waiting list” of interested manufacturers exist Working with manufacturers will ensure that emerging commercial technologies meet end-user needs Working with stake-holders will assist in selection of proper technology 10

11. Innovation for Our Energy Future SINTERCOM Sensor INTERlaboratory COMparison (SINTERCOM) International Collaboration The National Renewable Energy Laboratory (NREL) of the US Department of Energy (DOE) Institute for Energy of the European Commission’s Joint Research Centre (JRC) Round-Robin Testing Independent, unbiased assessment of sensor performance Opportunity to test more sensors Improvement of test methods 11

12. Innovation for Our Energy Future The SINTERCOM Protocol Technology Selection & Procurement Identify and acquired representative technology type Provide 3 units to each participating laboratory Technology Testing Round 1: Analytical performance assessment Performed in each lab on 3 units Round 2: Analytical performance assessment; Exchange 3 units and repeat Round 1 protocol Validation of laboratory Round 3: Interferent / poison and Long-term stability Exchange and Compare Data after each round 12

13. Innovation for Our Energy Future SINTERCOM Round-Robin Test (Round 1) Test Plan Standard Condition 25°C, 1 Bar, 50% RH (unless noted) Initial/Final Sensor Calibration Standard Condition First test of Round 1 1% and 2% Certified Standards First and last test in each round Linear Range Test Standard condition 7 concentrations (0 to 2%) ascending and descending 13

14. Innovation for Our Energy Future SINTERCOM Round-Robin Test (Round 1) Test Plan Short Term Stability Standard Condition 4 concentrations 0.0, 0.2, 1.0, 2.0 % Hydrogen Repeated 9X in 48 hours Environmental Stresses Temperature (-20 to 85°C) Pressure (0.8 to 1.2 Bar) Moisture (<5 to 85%) “Standard Condition” 1 variable parameter Performed 1X for each condition Range restricted to manufacturer spec 14

15. Innovation for Our Energy Future Test Sequence and Parameters (Round 1 and Round 2) 15

16. Innovation for Our Energy Future SINTERCOM Round-Robin Test NREL NREL tests on Unit 1 1L/min Flow Rate Fixed Step Duration 1 hour Final Indication after 59 min Test performed at 0, 0.2, 1.0, 2.0 0.2 below LDL of instrument JRC JRC tests on Unit 2 0.35L/min Flow Rate Fixed Step Duration 45 min Final Indication after 44 min Test performed at 0, 0.6, 1.0, 2.0 Protocol adjusted 16

17. Innovation for Our Energy Future SINTERCOM: Short-Term Stability (1%) NREL Unit 1 ( ♦ ) JRC Unit 2 ( □ ) Vendor ISO As received (no recalibration)“Field” Calibrated Instrument Performance in SINTERCOM (SHORT TERM STABILITY) - Unit 1 (♦) NREL and Unit 2 tested at JRC (□) - Excellent consistency between laboratories and between two units - Similar results for all six units - Sensor performance as compared to ISO (▬) and Vendor Specifications (▬) - Sensor meets vendor’s spec (±20%), needs “calibration” for ISO (±10%) - Specifications are “arbitrary” and depend on USER REQUIREMENTS 17

18. Innovation for Our Energy Future SINTERCOM: Temperature Stress Test Instrument Performance in SINTERCOM (TEMPERATURE STRESS TEST) - Unit 1 (♦) NREL and Unit 2 tested at JRC (□) - Excellent consistency between laboratories and between two units - Similar results for all six units - Sensor performance as compared to ISO (▬) and Vendor Specifications (▬) - Sensor meets vendor’s specification (±20%) except at very low T - Sensor meets ISO T specification (±30%) except at very low T - Specifications are “arbitrary” and depend on USER REQUIREMENTS Vendor ISO 18 NREL Unit 1 (♦) JRC Unit 2 (□)

19. Innovation for Our Energy Future SINTERCOM: Pressure Stress Test Instrument Performance in SINTERCOM (PRESSURE STRESS TEST) - Unit 1 (♦) NREL and Unit 2 tested at JRC (□) - Excellent consistency between laboratories and between two units - Similar results for all six units - Sensor performance as compared to ISO (▬) and Vendor Specifications (▬) - Sensor meets vendor’s specification (±20%) except at very low P - Sensor meets ISO P specification (±30%) - Specifications are “arbitrary” and depend on USER REQUIREMENTS Vendor ISO 19 NREL Unit 1 (♦) JRC Unit 2 (□)

20. Innovation for Our Energy Future SINTERCOM: Moisture Stress Test Instrument Performance in SINTERCOM (Moisture STRESS TEST) - Unit 1 (♦) NREL and Unit 2 tested at JRC (□) - Excellent consistency between laboratories and between two units - Similar results for all six units - Sensor performance as compared to ISO (▬) and Vendor Specifications (▬) - Negligible effect of moisture on sensor performance - Sensor meets vendor’s (±20%) and ISO (±30%) specification - Specifications are “arbitrary” and depend on USER REQUIREMENTS Vendor ISO 20 NREL Unit 1 (♦) JRC Unit 2 (□)

21. Innovation for Our Energy Future SINTERCOM Status Round 1 completed for initial technology Reviewed with manufacturer and between laboratories Round 2 is starting Instrument Exchange completed Round 3 is pending Additional technology Second technology has been selected, acquired, and distributed Additional technology has been selected Representative of alternative sensor types 21

22. Innovation for Our Energy Future Sensor Interlaboratory Comparison (SINTERCOM) Support of Technology Development Independent, unbiased assessment of performance Expert analysis and feed back opportunities Exposure to international markets Test Laboratories Venue to critically evaluate sensor test protocols Validate competences of participating laboratories End-User benefits Information on sensor performance Importance of sensor use 22 Round-Robin Testing of Hydrogen Sensors BENEFITS

23. Innovation for Our Energy Future Summary 23 Sensors are reliable and well established safety components Codes & Standards will require the use of hydrogen safety sensors SINTERCOM is an international effort to improve hydrogen sensors First Round testing has been completed Strong agreement among units and between labs Additional technology has been selected Results will be compiled and reported

24. Innovation for Our Energy Future Thank You The National Renewable Energy Laboratory (NREL) of the US Department of Energy (DOE) W. Buttner, R. Burgess, C. Rivkin, M. Post Institute for Energy of the European Commission’s Joint Research Centre (JRC) L. Brett, G. Black, F. Harskamp, P. Moretti