Production of Hydrogen from Renewable Electricity: The Electrolysis Component Workshop on Electrolysis Production of Hydrogen from Wind and Hydropower NREL DC Office, Sept 8,2003.

Renewable Electricity- Infrastructure Meets DOE Hydrogen Feed Stock Strategy:  Primary Indigenous Sources: Wind, “run of river” hydro, solar  No carbon-emissions in electricity-hydrogen generation  Mature technology, established cost progression But can we meet DOE cost target ? $2.00 per kg at plant gate

Wind-Electrolysis Integration Process Capabilities:  > 90% of energy consumed by cells 20 bar)  generator following load  trade off between efficiency and cap $. Efficiency inversely proportional to cell surface area (cap$).  design to avg efficiency/wind resource: Plant X = 53 kWh/kg Plant 2X = 47.5 kWh/kg  “Current sink” characteristic  Voltage regulated by cells  Response like “leaky capacitor”  Value of by-products  Electricity on demand  Oxygen $25 per tonne =.4 cent per kWh  D 2 0 ?

Cost Target Implications  Simple Cost Model :  $/kg = Efficiency  (price of electricity) + [Annual (CRF+O/M)]  (Capital Cost per kg/h)÷ [(capacity factor)  8760 h/y]  Implications  For Annual (CRF +O/M) =20%  Capacity Factor =.35  Avg. Efficiency = 50 kWh/kg (=approx 80% wrt HHV) Cost of Wind Electricity`2.5 ¢/kWh3.0 ¢/kWh Cost of Electrolyser Avg Efficiency)$12,000/kg/h$8,000/kg/h

Two Market Models:  Wind-Hydrogen Generation Model  Wind- Hydrogen&Electricity Generation Model

Capacity Factor Matching in Wind- Hydrogen Generation Model  Single tier market design: Large-Scale Hydrogen Production  Tech Implications  Power Conversion: Optimize DC-Wind conversion based on electrolysis cells  Optimize cell size to scale of production – cell cost key  Maintaining grid stability with high electrolysis penetration  Pressurized cell design amenable to distribution pipeline

Capacity Factor Matching in Wind Hydrogen-Electricity Generation Model  Two tier market design:  Primary Market : Electricity Secondary Market: Hydrogen  Deregulated electricity market design with environmental credits for emission avoidance  Capture distributed generation benefit  Closer to market  Higher value electricity market supports secondary hydrogen production (energy storage)  Technology Implications  Controls  System Cost Key

Cell Technology Product NameStuart CellEI-250M-PlatformIMET Cell TechnologyUnipolar Gen IIUnipolar Gen II DEPBipolar Production Capacity 5 Nm3/h to 1000 Nm3/h 1000 Nm3/h and greater 50 Nm3/h and greater 1 Nm3/h to 100 Nm3/h Cell PressureAtmospheric up to 25 bars Typical Application Generator Cooling Hydrogen Peroxide Fiber OpticsBus filling station

Technical Challenges  Intermittent operation; long term electrode stability  Economic scale of cell; cost highly dependant on cells  Gas purity process dynamics:  Controlling gas/liquid separation  Reducing bypass cell currents  Cell pressurization  Power conversion & controls

Conclusions: DOE cost targets are very challenging Early pathways to develop infrastructure: Replace SMR hydrogen under right market conditions (NG conservation/CO2 mitigation): heavy oil upgrading ammonia production Distributed “hydrogen&electricity generation model” may play role in early infrastructure development – if value put on green electricity/green hydrogen.