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Kevin Harrison* Robert Remick*Aaron Hoskin
Gregory Martin*
World Hydrogen Energy Conference
Essen, GermanyMay 19, 2010
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.
NREL/PR-560-48269
Hydrogen Production: Fundamentals and Case
Study Summaries
20% Wind by 2030 Scenario
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2000 2006 2012 2018 2024 2030
Cum
ulat
ive
Inst
alle
d C
apac
ity (G
W) Offshore
Land-based
2010
As of December 31, 2009 - 34,863 MW of wind power have been installed across the United States.
Challenges to 20%
• Growth in installations – 8 GW installed in 2008– 9 GW installed in 2009– Total 34 GW 2009
• 50 GW offshore– Cape Wind approved– 130 wind turbines– 420 MW
• Performance is critical– Gearbox reliability– Capital cost– Capacity Factor– O&M
Competitive Energy Storage Technologies
Source: Energy Storage Association
Solar Energy
Heat
Hydrogen
Thermolysis
Mechanical Energy
Electricity
Electrolysis
Biomass
Thermo-Chemical & Biological
ConversionPhotolysis
Sustainable Paths to Hydrogen
Sustainable Hydrogen Potential
Wind Biomass
Solar
• Examine benefit to utility by time shifting wind and PV energy with hydrogen production
• Research optimal wind/hydrogen through systems engineering and power electronics integration
• Characterize and control wind turbine/PV and H2-producing stack
• Evaluate synergies from co-production of electricity and hydrogen
NREL/Xcel Energy Wind to Hydrogen - Objectives
New Wind2H2 Configuration
PV Configuration Testing
Direct connect versus various input voltages (Ein) through power controller
85% -92%
100%
Round I - PV Powered Electrolysis• Onboard power electronics account for 15 – 30% of the
overall electrolyzer system cost • The data illustrates improvement in energy capture to stack
when using MPPT power electronics• Testing showed a 10% – 20% increase in energy capture
depending on input voltage to power electronics
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9:18 9:38 9:59 10:19 10:39 10:59 11:19 11:39 11:59
Time of Day
Sta
ck P
ower
[W]
E-130 connected through MPPT
power electronics
E-120 direct connect to PV Direct connect
MPPT power electronics
PV-to-Stack Optimization
• Installed 10-cell stack in series with existing 20-cell stack to better align PV and stack operating points
• Improved PV-to-stack sizing enabled 2nd phase direct coupling versus MPPT power electronics
Impact of Shifting Operating Point
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Cur
rent
(A)
PV Array IV
20-cell stack Relocated with 10 additional cells
PV array maximum power point
Solar Irradiance
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ianc
e [W
/m^2
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ck P
ower
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ck P
ower
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Electrolyzer Fault
Performed IV sweeps of PV
array
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% T
ime
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% T
ime
Direct Coupling v. Power Electronics
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Rat
io S
tack
Pow
er/Ir
radi
ance Power Electronics
with MPPTDirect Coupling
General Electrolyzer System Data
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0.020
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Hyd
roge
n Fl
ow [k
g\h]
Although stack efficiency is higher at lower current the hydrogen flow (thus system efficiency) is zero at currents
below 15 A
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Sta
ck E
ffici
ency
[%]
Electrolyzer consumes hydrogen to maintain the desiccant drying system
New techniques and incremental improvements in drying systems will
improve system efficiency
Higher pressure electrolyzers will dissolve more hydrogen that is also
wasted
350 bar Vehicle Fueling SystemNew System Components• Storage tank, compressor and
dispenser– 18 kg @ 6000 psi– 120 kg @ 3500 psi
• June 2010– Additional 6000 psi storage– Cascade filling– Total 250 kg (including 3500 psi tanks)
• 9 months of refueling A-Class Mercedes (~2 kg, 110 miles)
• Proterra Fuel Cell Bus – March 2010, 20 kg
• Yesterday, Ford H2 ICE shuttle leased by NREL
Integrated Renewable Energy SystemIntegrated Systems• 5 kW fuel cell (PEM)• 5 kW to 10 kW PV array• 10 kW wind turbine
TEST: Dynamic response (both DC and AC) of fuel cell with both PV and wind systems
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Irrad
ianc
e [W
/m^2
]
7.25 kWh / m2
1 minute → Increase 536 W/m2
→ Decrease 518 W/m20
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Irrad
ianc
e [W
/m^2
]
Variable Stack Current Testing
Comparison TestingPEM: 3-stack design withIndividual power supplies
Alkaline: New stack installation
Test: Long duration testing of stacks with highly variable (wind profile) current
WIND ENERGY & HYDROGEN INTEGRATION
International Energy Agency, Hydrogen Implementing Agreement, Annex 24
To explore in detail all possible issues (technical, economical, social,
environmental, market and legal) related to hydrogen production using electrolysis with
wind energy.
National Renewable Energy Laboratory Innovation for Our Energy Future
Recent Publications
Technical ReportNREL/TP-581-44082April 2009
Technical ReportNREL/TP-TP-550-44103December 2008
http://www.nrel.gov/hydrogen/proj_wind_hydrogen.html
Thank you for your attention!
Questions?