NREL Wind to Hydrogen Project: Renewable Hydrogen ... · Renewable Hydrogen Production for Energy...

NREL Wind to Hydrogen Project: Renewable Hydrogen Production

for Energy Storage & Transportation

NRELHydrogen Technologies and Systems Center

Todd Ramsden,Kevin Harrison, Darlene Steward

November 16, 2009NREL/PR-560-47432

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 Wind2H2 RD&D Project

• The National Renewable Energy Laboratory in partnership with Xcel Energy and DOE has designed, operates, and continues to perform testing on the wind-to-hydrogen (Wind2H2) project at the National Wind Technology Center in Boulder

• The Wind2H2 project integrates wind turbines, PV arrays and electrolyzers to produce from renewable energy

National Renewable Energy Laboratory 2 Innovation for Our Energy Future

Sustainable Paths to Hydrogen

Solar Energy

Heat

Hydrogen

Thermolysis

Mechanical Energy

Electricity

Electrolysis

Biomass

Thermo-Chemical & Biological

ConversionPhotolysis


Hydrogen Potential from Sustainable Resources

Wind Biomass

Solar


20% Wind Energy by 2030 Scenario

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2000 2006 2012 2018 2024 2030

Cum

ulat

ive

Inst

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d C

apac

ity (G

W) Offshore

Land-based

2008


How Much Wind is Available in the U.S.?

- 200 400 600 800 1,0000

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Leve

lized

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t of E

nerg

y, $

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10% of Existing Transmission Capacity Available to Wind

2010 Costs w/o PTC, $1,600/MW-mile, w/o Integration costs Source: Black & Veatch/NREL

20% Goal


Technology Challenges to Meet 20% Goal

• Massive growth in installations – 8 GW installed in 2008– ~29 GW total as of 2009 – Over 300GW by 2030

• Widely distributed across the nation– Many high wind sites– Substantial installation in

moderate resource areas– Some offshore is needed

• Performance is critical– Capital cost– Capacity Factor– O&M

• Every 1 ¢/kWh of cost reduction saves the nation over $10 billion per year at 20% penetration


Wind2H2 Project – Overall Goal

• Provide RD&D to help DOE achieve it cost target for hydrogen production from wind-based water electrolysis of $4.80/gge by 2012 and to <$3.00/gge by 2017

Challenges• Reduce capital costs of electrolysis

system through improved designs and lower cost materials

• Develop low-cost hydrogen production from electrolysis through integration with renewable electricity sources

• Develop strategies for low cost hydrogen production from electrolysis through utility coordination


Wind2H2 Project – Main Objectives

• Research the cost and capability of “time shifting” wind and PV energy through utility-scale hydrogen-based energy storage

• Research optimal wind/hydrogen through systems engineering

• Characterize and control wind turbine/PV and H2-producing stack

• Evaluate synergies from co-production of electricity and hydrogen

• Compare response and performance of alkaline and PEM electrolyzer technologies

• Realize efficiency gains though simplified and integrated power controllers

• Working towards ‘ideal’ wind to hydrogen – Simplifying PE, common controls, closely

coupling wind input to stack, electricity regulation


Wind2H2 System Operating Modes


PV Configuration Testing

Direct connect versus various input voltages (Ein) through power controller

65% -90%

100%


PV Powered Electrolysis

• Onboard power electronics account for 15 to 30% of the overall electrolyzer system cost

• Minimize redundant components• Test data illustrates improvement in energy capture

to stack when using MPPT power electronics• Testing showed a 10% – 20% increase in energy

capture

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k Po

wer [

W]

E-130 connected through MPPT

power electronics

E-120 direct connect to PV

Direct connect

MPPT power electronics


10kW Wind Turbine Powered Electrolysis

• Initial tests with third generation power electronics, wind speed measurement and control algorithm indicate further improved energy capture of wind electricity into hydrogen production

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Planned increased energy capture from

Gen 2 to Gen 3

Increased energy capture from Gen 1

to Gen 2

Available wind power= Preliminary results

showing increased energy capture with new TSR algorithm. Algorithm is currently being tuned for stability.


100kW Wind Turbine Powered Electrolysis

• Instrumented power signal from 100 kW wind turbine to drive 33 kW alkaline stack current to follow power available from turbine

020406080

100120140160180200220240260

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ow [N

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Grid AC

Power Data

Varying Stack Current

100 kWWind

Turbine


Electrolyzer System Efficiency

• Wind2H2 system used to assess electrolyzer performance • Stack and system efficiency of alkaline (33 kW stack, 40 kW system)

and PEM-based (6 kW stack, 7 kW system) measured

Efficiency PEM Electrolyzer Alkaline Electrolyzer

LHV HHV LHV HHV

Stack Efficiency

Low Current 80% (5A) 95% (5A) 78% (30A) 92% (30A)

Rated Current 63% (135A) 75% (135A) 59% (220A) 70% (220A)

System Efficiency

Low Current 0% (15A) 0% (15A) 0% (35A) 0% (35A)

Rated Current 49% (135A) 57% (135A) 35% (220A) 41% (220A)


Cost Analysis

• Cost analysis performed based on NREL’s power electronics optimization and testing and on our electrolyzer cost analysis study

• Large centralized system capable of 50,000 kg per day production

• Optimized power conversion system due to a closer coupling of the wind turbine to the electrolyzer stack can reduce the total cost of hydrogen by 7%.

Capital Component (uninstalled) Baseline System

Optimized System

1.5 MW Wind Turbine

Rotor $248,000 $248,000

Drive Train $1,280,000 $1,180,000

including power electronics $100,000 $0

Control System $10,000 $10,000

Tower $184,000 $184,000

Balance of Station $262,000 $262,000

2.33 MW Electrolyzer $1,570,000 $1,350,000

including power electronics $220,000 $0

New Power Electronics Interface $0 $70,000

Resulting Hydrogen Cost ($/kg) $6.25 $5.83


350 bar Vehicle Fueling System

• Outdoor rated compressor• 400 bar tank (18 kg)• 350 bar non-communication fill

dispenser• 1.8 kg (110 mile range) Mercedes-

Benz FC vehicle


Key Findings from Wind2H2 RD&D

System Efficiency (HHV): At rated stack current…– The PEM electrolyzer system efficiency of 57% – The alkaline system had a system efficiency of 41%

• H2 production about 20% lower than the manufacturer’s rated flow rate• 50% system efficiency would be realized if rated flow were achieved

Cost Reductions from Power Electronics Optimization:– Analysis showed a potential 7% reduction in cost per kg of

hydrogen based on capital cost improvement• Projected cost of hydrogen falling to $5.83/kg from a baseline of

$6.25/kg

Energy Transfer Improvements: PV configuration testing compared direct-connection to the electrolyzer stack with a connection through power electronics– The MPPT power electronics system captured between 10% and

20% more energy than the direct-connect configuration


Hydrogen-Based Energy Storage Cost Analysis

Project Objective:• Evaluate the economic viability of the use of hydrogen for

medium- to large-scale energy storage applications in comparison with other electricity storage technologies

Project Background:• FY2009 study builds upon and expands on an initial scoping

study of hydrogen-based energy storage conducted in FY2008• Benchmarking against competing technologies (batteries,

pumped hydro, CAES)• Expanded analysis of PEM fuel cells and hydrogen combustion

turbine• Analysis of production of excess hydrogen for vehicles• Preliminary analysis of environmental impactsNational Renewable Energy Laboratory 19 Innovation for Our Energy Future

Energy Storage Scenario

Nominal storage volume is 300 MWh (50 MW, 6 hours)– Electricity is produced from the storage system during 6 peak hours

(1 to 7 pm) on weekdays– Electricity is purchased during off peak hours to charge the system

Electricity source: excess wind / off peak grid electricity – Assumed steady and unlimited supply during off peak hours (18 hours

on weekdays and 24 hours on weekends)– Assumed fixed purchase price of 3.8¢/kWh with sensitivities run at

2.5¢/kWh and 6¢/kWhNational Renewable Energy Laboratory 20 Innovation for Our Energy Future

Analysis Framework

Major Assumptions• No taxes or transmission charges are included in the analysis• The supply of off peak and/or renewable electricity is unlimited• Costs are presented in $2008Timeframes• High cost or “current” technology • Mid range cost

– Some installations exist – Some cost reductions for bulk manufacturing and system integration have

been realized– Installations are assumed in the near future; 3 to 5 years.

• Low range cost – Estimates for fully mature technologies and facility experience

Cost analysis performed using the HOMER model– Results are presented as levelized cost of energy; $/kWh or $/kg for hydrogen


Energy Storage Study Findings

0.0

20.0

40.0

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100.0

120.0

FC/ abo

vegro

und

FC/ geo

logic

Hydrog

en ex

pans

ion/co

mbusti

on tu

rbine

NiCd batt

ery

NaS ba

ttery

Vanad

ium re

dox b

attery

Pumpe

d hyd

roCAESLe

veliz

ed c

ost o

f out

put e

lect

ricity

(¢/K

Wh)

28 24 19

83

25 28

13 10

Comparison of hydrogen and competing technologiesNational Renewable Energy Laboratory 22 Innovation for Our Energy Future

Analysis Results - Hydrogen

Hydrogen fuel cell with geologic storage

0.14 0.18 0.22 0.26 0.3 0.34 0.38 0.42 0.46 0.5 0.54 0.58

Electrolyzer capital cost

Geologic storage capital cost

Fixed O&M

Electrolyzer efficiency

Fuel cell capital cost

Electricity price

HIGH-COST CASE



Fixed O&M



Electricity price

MID-RANGE CASE



Fixed O&M



Electricity price

LOW-COST CASE

Cost of Energy ($/kWh)

$0.24

$0.50

$0.18


Analysis Results - Hydrogen

Hydrogen gas turbine with geologic storage

0.14 0.16 0.18 0.2 0.22 0.24 0.26 0.28 0.3 0.32 0.34

Steel Tank capital cost

Fixed O&M


Combustion Turbine capital cost


Electricity price

HIGH-COST CASE

Geologic Storage capital cost

Fixed O&M




Electricity price

MID-RANGE CASE

Geologic Storage capital cost

Fixed O&M




Electricity price

LOW-COST CASE

Cost of Energy ($/kWh)

$0.17

$0.19

$0.26


Recent Publications

Technical ReportNREL/TP-581-44082April 2009

Technical ReportNREL/TP-TP-550-44103December 2008

http://www.nrel.gov/hydrogen/proj_wind_hydrogen.html


Acknowledgments

Xcel Energy– Frank Novachek– Vicki McCarl– Brad Hollenbaugh

DOE– Roxanne Garland– Richard Farmer– Monterey Gardiner

Contractors– John Cornish (EPC)– Marc Mann (Spectrum)

NREL– Kevin Harrison– Greg Martin– Keith Wipke– George Sverdrup– Robert Remick– Genevieve Saur– Bill Kramer– Ben Kroposki– Mike Stewart


NREL Wind to Hydrogen Project: Renewable Hydrogen ... · Renewable Hydrogen Production for Energy...

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