long life pem water electrolysis stack experience and ... · long life pem water electrolysis stack...
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Long Life PEM Water Electrolysis Stack Experience and Future Directions
E. Anderson, K. Ayers, C. Capuano and S. Szymanski
Technical ForumHannover Messe
Germany9 April 2013
Proton’s Markets, Products & CapabilitiesPower Plants
Heat Treating
Semiconductors
Laboratories
Government
• Complete product development, manufacturing & testing
• Turnkey product installation• World-wide sales and service• Containerization and hydrogen
storage solutions• Integration of electrolysis into RFC
systems
2
Over 10 MW Shipped – Future Growth from MW-Scale PEM Electrolysis
Critical Needs for Energy Storage
• Renewable energy is growing rapidly world-wide in both wind and solar– Inherent intermittency has more impact as RE becomes a
larger portion of the grid capacity
– Up to 20-40% of wind energy can be stranded without storage
• Need generation technologies for storing excess renewable capacity & balancing loads on the grid
• Energy storage can also provide a linkage between utilities & transportation
3
Energy Storage Segmentation Map
4
Courtesy of Siemens AG, 2012
Sandia National Laboratory Analysis
Batteries Electrolysis
Storage Capacity <10 hours
Expandable with inexpensive storage
Cycle Life Limited UnlimitedCost Challenges Yes
Leverage fuel cell scale up
Scale Unproven 100 year technology
5
Cost analysis shows cost effectiveness of hydrogen RFCs
Sandia public report: SAND2011-4845
Markets for MW Electrolysis• Transportation market
– H2 infrastructure plans in Europe, Asia• Renewable energy storage
– 10’s of GW’s of wind/solar energy capture– Power-to-gas
• Biogas market– Methanization
• Multi-billion dollar opportunity in each• MW-scale electrolysis needed
– Targeting 1-2 MW product scale-up
6
H2 Energy Product Attributes• Reliability – Cannot afford down-time or high replacement
costs
• Cost – Price targets for energy market apps more difficult (Capex vs. Opex)
• Load-following – Need to handle fast response of varying renewable power
• Operating Range – Need to handle wide variability of available renewable power(i.e. 100% turndown)
• Efficiency – Cost of electricity impact (Opex)
• Scale – MW-class electrolysis required
7
Today…
• Proton’s PEM-based hydrogen generators are demonstrating excellent reliability in industrial applications
• Cell stack technology is the most reliable component in the system
• New energy applications present capital as well as operating cost challenges
• Necessary technology advances are the biggest risk to established durability and reliability
8
Cell Stack Reliability – Over the past 6 yrs…
9
Corrective actions in place to address top 2 failure modes
Hundreds of millions of cell-hours of field experience>> 99% reliability
Established PEM Stack Durability
10
~60,000 hour life demonstrated in commercial stack designsNew designs have no detectable voltage decay
1.4
1.8
2.2
2.6
3.0
0 10,000 20,000 30,000 40,000 50,000 60,000
Average Cell Potential
(Volts, 50oC)
Operating Time (Hours)
2003 Stack Design:1.3 A/cm2
4 µV/cell hr Decay Rate
200 psig (13 barg)
Proton Energy SystemsIn-House Cell Stack Endurance Testing
2005 Stack Design:1.6 A/cm2
Non Detectable Decay Rate
11
Technology Roadmap Development
• Clearly defined pathways enable directed research– Product, cell stack, and balance-of-plant
• Balance portfolio with near and long term R&D• Leverage 3rd party funding to subsidize internal R&D
– Utilize military and aerospace as early adopters– Develop key partnerships to broaden skill base
• Feed into commercial markets as proven
NSF ARPA- E DOE-EERE ONR CERL TARDEC
Materials Feasibility Applied Deployable Prototypesresearch Demonstration R&D
U.S. Funding Agencies:
Development Stage/Risk Level
PEM Cost and Efficiency Limitations
12
• Flow field, membrane electrode assembly, and labor are high impact cost areas
• Efficiency losses dominated by membrane ionic resistance and O2 reaction overpotential
System vs. stack breakdown
Cell stacksElectronics
Technology Roadmap Execution• Clearly defined pathways enable directed research
Page 13
0-18 months 1.5-3 years 3-5 years
Catalyst Cost & Efficiency: Loading Reductions (Process and Structure) and Composition Optimization
Thinner Membranes: Improved Mechanical and Thermal Stability and Reduced Crossover
Flow Field Material and Coatings for H2/O2 protection
Scale Up in Capacity and Pressure
Manufacturing Development for High Volume and Automation
Cell Stack Technology Roadmap ProductionImplemented
Funded
Not Yet Funded
Cost Reduction InitiativesNoble Metal Reduction Flow Field Cost3M NSTF electrode:5% of current catalyst loading
New design with ~50% less metal
14
1
1.2
1.4
1.6
1.8
2
2.2
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Potential (Vo
lts)
Current Density (Amps/cm2)
3M Cathode #1, 8 mil total3M Cathode #2, 8 mil totalProton Baseline , 7 mil
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Potential (V)
Current Density (A/cm2)
Approximate current production range
90 micron
60 micron
Adv membrane: Enables 2X current(lower Capex)
Reduced voltage(lower Opex)
Lower Cost Membranes
Efficiency Needs and Progress: Membrane
• Legacy membrane does not hold up at desired thicknesses and pressures
• Optimization of Tg, IEC, and reinforcement show good mechanicialdurability
Page 15
1.55
1.65
1.75
1.85
1.95
2.05
0 2000 4000 6000 8000 10000
Volta
ge (V
)
Time (h)
2mil high Tg membrane(160 amps, 200 psi, 80°C)
Cost Needs and Progress - Catalyst
• Engineered structures for ultra-low PGM loadings
16
1
1.2
1.4
1.6
1.8
2
2.2
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Potential (Vo
lts)
Current Density (Amps/cm2)
3M Cathode #1, 8 mil total3M Cathode #2, 8 mil totalProton Baseline , 7 mil
Polarization curves: 3M loading < 1/20th baseline, Brookhaven <1/30th loading
3M NSTF
Brookhaven GDE approach
Cost Needs and Progress: Flow Fields• New bipolar cell assembly design: 50% metal reduction
• Alternative coatings: Eliminates process stepsand mitigates hydrogenembrittlement
17
Flowfield/Bipolar Plate Reliability• Typical materials are semi-
precious metals– Precious metal coatings
added to reduce resistance• Susceptible to oxidation
(anode) or embrittlement (cathode) with prolonged operation
• Need lower cost alternatives• Investigating impact of
process methods & alternative non-precious metal coatings on durability
18
0%
20%
40%
60%
80%
100%
0 200 400 600 800Hyd
rogen Uptake vs. Baseline
Time (h)
Baseline
Treatment 1
Treatment 2
Nitrided
Accelerated H2 Exposure Testing(100 hrs 10 yr operation)
Intermittency and Variable Load Input• Electrolysis is well suited to load following
– Stable performance– Rapid response time to current signal– Tolerance to variable power input
19
Courtesy of NREL
50 ms response time demonstrated
Electrolysis Stack & System Development
20
650 cm2
30 Nm3/hr65 kg/day
1.70
1.80
1.90
2.00
2.10
2.20
2.30
2.40
0 5000 10000 15000 20000 25000
Avg
Cel
l Pot
entia
l (V
)
Operating Hours
Large Area Cell Short Stack1032 amps, 30 barg, 50°C
600 cm2 Stack Development• Improvement in bipolar plate design
– Current 86 cm2 design tested to over 1 million cell hours
– CFD modeling shows more uniform flow• Demonstrated operation up to 30 bar
– >20,000 hours validated on 3-cell– > 1,500 hours on 10-cell stack– Full-scale +50 kg/day stack scale-up in process
21
Proton Stack Performance Progression
• Additional testing at current densities >5 A/cm2
22
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
0 0.5 1 1.5 2 2.5 3
Potential (Vo
lts)
Current Density (A/cm2)
Technology Progression
Baseline, 50CAdvanced Oxygen Catalyst, 50CAdvanced membrane, 80CAdvanced cell design, 80C
Current Stack(~70% Eff (HHV)
Advanced Stack (>86% Eff (HHV)
H2 Generation Capacity Tradeoffs• Stack capable of current density• Evaluate impact on BoP ratings
− Power buss− Thermal control− Gas drying
• Added cost of lower utilization extra capacity?
23
15%
32%
13%
25%3%
12%53%
Power supplies
Balance of plant
MEA
flow fields and separators
balance of cell
balance of stack
24%
48%
5%
23%
StackSystem
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
Cell Po
tential (Vo
lts)
Current Density (A/cm2)
80˚C, 30 bar H2 Pressure
Current Generation MEANext‐Gen MEA1Next‐Gen MEA2
MW-Scale Product Development Pathway
• Multi-stack architecture– Consistent with H- and C-Series products
• Large active area stack platform– 3X Increase over C-Series stack– Prototype already developed and tested– Advanced design to deliver 40% cost reduction
• Open-frame skid modular plant configuration– Transition from previous
fully-packaged designs• Trade-off Capex vs. efficiency
for specific market applications
Large Active Area PEM
Stack
MW-scale concept
24- Proton OnSite Proprietary and Confidential -
Scale-Up Cost Reduction Trajectory
• Straight-forward engineering scale-up of current products• Critical technology elements already developed
0%
20%
40%
60%
80%
100%
C30 0.5 MW 1 MW 2 MW 2 MW Adv
Perc
ent C
ost R
educ
tion
Electrolysis System Size
25- Proton OnSite Proprietary and Confidential -
26
Summary
• Industrial PEM electrolysis systems have excellent reliability track record
• New energy applications will challenge that reliability as technology advancements to drive cost and reliability are adopted
• Technology roadmap is guiding progress and funding of continued development
• Market needs for hydrogen energy storage are emerging rapidly
• Proton is a leader in this technology space