SCHATZ ENERGY RESEARCH CENTER Comparative Performance of Electrolysis Cell Stacks at the HSU Hydrogen Fueling Station Meg Harper Schatz Energy Research Center Humboldt State University National Hydrogen Association Annual Meeting May 4, 2010 © 2010 Schatz Energy Research Center

Chris Capuano Proton Energy Systems Greg Chapman and Peter Lehman Schatz Energy Research Center

Outline Introduction Station Overview New Cell Stack Specifications Performance Improvements Conclusions Questions

Energy in H 2 out The Experiment Compare the performance of Proton’s Next Generation cell stack to the originally installed stack LHV of H 2 Produced Energy Consumption of Electrolyzer Efficiency =

HSU Hydrogen Fueling Station Northernmost and only rural station on California’s Hydrogen Highway Grand opening was September 4, 2008 SERC Director Peter Lehman cuts the ribbon opening HSU’s station as Congressman Mike Thompson, HSU President Rollin Richmond and SERC engineer and project manager Greg Chapman look on.

Fueling Station & Fleet Serves two vehicles: Hydrogen-powered Toyota Prius Toyota’s Fuel Cell Hybrid Vehicle (FCHV-adv)

Interpretive Sign The station generates H 2 with a Proton electrolyzer, compresses it to 420 bar storage with a PDC compressor, and dispenses it to vehicles at 350 bar with an FTI dispenser.

Electrolyzer Proton Systems HOGEN S40 PEM electrolyzer 2.3 kg H 2 per day % pure hydrogen H 2 tested by Atlantic Analytical Lab and found to have no detectable impurities and be suitable for fuel cell vehicles 200 psig maximum output pressure

Data Acquisition and Instrumentation DAQ recorded: Power to the electrolyzer Mass flow of hydrogen from the electrolyzer Manually recorded: Cell Stack Current using a current shunt attached to a Fluke 73 III multi-meter Cell Stack Voltage using a Fluke 45 multi-meter Cell Stack temperature as measured by the unit’s thermistor in the water circulation system

Hydrogen Water Separator Tank Hydrogen Gas Dryer

Heat Exchanger Bypass Adjustable valves allow water to partially bypass the heat exchanger to control the operating temperature of the cell stack System can run at temperatures up to 60 ˚C Testing occurred at 34 ˚C and 56 ˚C

Next Generation Cell Stack Proton Energy Systems developmental model Bipolar plate design which replaces frame, flow-field, and separator plate with a single component Reduction from 29 parts to 9 parts per stack

Experimental Results

Results of Cell Stack Performance Tests Cell Stack Temp (˚C) Power (W) Specific Energy Consumption (kWh/kg H 2 ) Efficiency (%) % Improvement in Efficiency Original New % Original New % LHV of H 2 Produced Energy Consumption of Cell Stack Efficiency =

Power Use Error bars = 95% Confidence Interval

Overall Electrolyzer Energy Consumption Measured Original (Low Temp) Measured New (High Temp) 78 kWh/kg70 kWh/kg This is a comparison of overall energy consumption of the electrolyzer using the original cell stack operating at normal temperatures to the new cell stack operating at elevated temperatures. The energy use is shown for a measured H 2 production rate of 18.0 slm.

Conclusions The new cell stack is more efficient, improving by approximately 8.0% at low temperatures and 6.4% at high temperatures. Using the new stack at higher temperatures decreases the overall electrolyzer energy consumption by 10%. This still represents a specific energy density of 70 kWh/kg, highlighting the need to improve the entire electrolyzer system. The new stack has worked well for three months. If the HOGEN ran continuously, these efficiency improvements would save us approximately $800/year in electricity costs. At a larger station these savings would be more substantial.

Many Thanks to Proton Energy Systems and Our Original Project Sponsors: Chevron Technology Ventures CalTrans California Air Resources Board North Coast Unified Air Quality Management District O&M Industries HSU

Contact Information Schatz Energy Research Center Humboldt State University (707) Thank you

SCHATZ ENERGY RESEARCH CENTER Extra Slides for fielding questions

Hydrogen Water Separator Hydrogen Gas Dryer Measured Hydrogen Output

Hydrogen Water Separator Hydrogen Gas Dryer More Hydrogen Output

Hydrogen Water Separator Hydrogen Gas Dryer Less Hydrogen Output

SCHATZ ENERGY RESEARCH CENTER Major Equipment Costs EquipmentCost (USD) Electrolyzer$76,600 Compressor$46,600 Storage Tanks$45,100 Dispenser$62,500 Taxes and Shipping $22,200 Total$253,000

SCHATZ ENERGY RESEARCH CENTER Total Station Cost The total cost does not include the cost of 1300 ft 2 of land donated by HSU. CategoryCost (USD) Major Equipment$253,000 Balance of System$133,000 Labor$220,000 Indirect Costs$72,000 Total$678,000

SCHATZ ENERGY RESEARCH CENTER Interpretive Signs The station has interpretive signage to inform visitors about what we’re doing, why we’re doing it, and how the station works.

SCHATZ ENERGY RESEARCH CENTER Compressor PDC single stage diaphragm compressor 6000 psig maximum discharge pressure

SCHATZ ENERGY RESEARCH CENTER Two 6000 psig ASME hydrogen storage tanks with a total capacity of 12 kg 30 gallon ballast tank between electrolyzer and compressor Storage Tanks

SCHATZ ENERGY RESEARCH CENTER Dispenser FTI single hose dispenser 5000 psig fill pressure California Fuel Cell Partnership (CaFCP) fueling protocol and data support