January 30, 2018 © 2017 Proton Energy Systems, Inc.

Developing a Research Agenda for Utilization of Gaseous Carbon Waste Streams: Renewable Hydrogen

Dr. Kathy Ayers, Vice President, Research and Development

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Hydrogen Technology Background:Scale and Commercial Viability (Question 1)

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Renewable hydrogen today

•Context for decarbonization: Conversion of CO2 to chemicals is only sustainable with renewable sources of protons

•Currently only 4% of H2 globally is from non-fossil sources

•Steam methane reforming available at very large scale (>250 MT/day)• Carbon dioxide and energy intensive

•Electrolysis follows similar capital cost curve to date

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Low Temperature Electrolysis Comparison• PEM-based:

– Solid electrolyte enables differential pressure

– Reliability at scale = KOH

– Room for cost/efficiency growth

• Liquid KOH: – Corrosive electrolyte

– Enables non-noble metals

– Lower current density

OH-

2H2O

2e-

2H2 + 4OH-

4OH-

O2 + 2H2O

4e-

Alkaline

Anode CathodeH+

4H+

2H2

2H2O

O2 + 4H+

4e-

Acid

Anode Cathode

Commercial Emerging

• AEM-based: – Potential KOH/PEM hybrid

– Low cost materials with membrane advantages

– Still immature, short life

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Electrolyzer Technology Readiness

•KOH Electrolysis: Commercial for 90 years• Demonstrated field reliability; incremental cost reduction and scaling still possible

•Proton exchange membrane (PEM) electrolysis: Commercial for 20 years• 50 year history in defense/aerospace for O2 generation • Significant potential for cost and efficiency improvement through applied research• Demonstrated field reliability; approaching scale of KOH systems

•Anion exchange membrane (AEM) electrolysis: Pre-commercial• Membrane stability a major issue, ~1000 hour durability; some prototypes fielded

•Solid oxide electrolysis (SOEC): Pre-commercial• Some demonstrations, 50-60 kW range; stability an issue with thermal cycles

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•KOH electrolysis: systems in the 10’s to 1000 kg/day range

• Installations to 60,000+ kg/day

•PEM electrolysis: systems in the <1 to 1000 kg/day range

•Still developing at larger scale

Scale/Scalability of Low Temperature Electrolysis

Integrated plants allow large scale

Modules at MW scale

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Fundamental Technology Limitations

•Catalyst supply: platinum group metals can support up ~2 GW/year (vs. decarbonization need of 150 GW/year)• Lower loading and higher current density can extend supply• Long term need to be working towards non-PGM materials or new pathways

•Anion exchange ionomers and membranes still limited in stability• Need material breakthroughs to achieve sufficient performance• Larger hydroxide ion limits diffusion; need to trade with balance of cell cost• Thermal instability further limits efficiency

• Low temperature technologies thermodynamically limited in efficiency• Electricity cost vs. capacity factor will dictate most favorable trade

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Technology Roadmap:Research Challenges and Opportunities(Questions 2 and 3)

Pt catalyst~1 mg/cm2

7-milPFSA

membrane

H2O = 1/2 O2 + 2H+ + 2e-

2H+ + 2e- = H2

H+

H+

H+

O2

H2O

O2

H2O

H+

H+

Carbon gas diffusion layer (GDL)

Titanium porous transport layer (PTL)

Titanium flowfield and separator

Titanium separator

IrOx catalyst~2 mg/cm2

Membrane

Oxygen flow fields and gas diffusion layers

Hydrogen flow fields and gas diffusion layers

Hydrogen catalyst

Oxygen catalyst

Electrolyzer cell schematic: Components not to scale

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CAPEX/OPEX: How do we get to <$2/kg?

Arun Majumdar, AWS workshop April 2016

•At $0.06/kWh, electricity dominates ($3/kg opex) – need direct technologies

• Low cost renewables change the landscape and strategy• Capital cost becomes much more important, especially at low capacity

One scenario:Low temp electrolysis

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Lifecycle Cost Analysis

•Detailed H2A model developed by DOE for cost of H2 production• Typically assumes 10 year stack life, 20 year

system life; includes annual O&M expenses• Finance assumptions also play into capital

contribution

•Cases shown demonstrate trades• CAPEX, OPEX, capacity factor, efficiency• 2014 NREL workshop: current CAPEX

~$1000/kW, potential for ~$400/kW• $400/kW roughly achieves $.53/kg at high

capacity factor

Capex vs. Opex scenario trade: H2@Scale

B.Pivovar, NREL, 2016

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Proton Exchange Membrane (PEM) Electrolysis: Product Context

•Proton OnSite: 20 year history in PEM electrolysis: 30+ MW installed from sub-watt to MW• 7-10 year life, >1 billion field cell hours demonstrated

NASA OGA system: ISS

Design legacy: How can we improve a 50-year technology?

•Originally used for life support• Closed environments (space, underwater)

• Replaced caustic KOH systems

•Optimized for high reliability, not cost/efficiency• Shock and vibration mil specs

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Cost and Efficiency Limitations

•Efficiency losses dominated by oxygen evolution and membrane resistance

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Ove

rpo

ten

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Current Density, mA/cm2

Anode Activation

Cathode Activation

Ionic

Electronic

Typical operating range

•Cost dominated by membrane electrode assembly and manufacturing volumes

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•Supply chain still underdeveloped/immature• Membranes, catalysts (especially O2), porous transport layers not optimized for

electrolyzer material requirements• Companies that are doing development mainly small

• Limited capabilities within device manufacturers for raw material development and manufacturing• Know what is needed but not necessarily how to make it

•Funding elements spread across multiple programs and agencies• Still need integration of components to make a viable device

Electrolysis Challenges

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Bipolar plate case study: credibility for cost reduction

•Program included mix of design, coatings/materials, manufacturing methods, fundamental analysis/modeling, and accelerated testing• Scaled by 6X in active area, 3X in cell count vs. prototype• Realized expected savings and achieved >500,000 cell hours

• In commercial production with >2000 cells fabricated

Computational fluid dynamics

Finite element analysis

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MEA Improvement Pathway

• Similar cost reduction opportunity as bipolar plate

• Requires catalyst, membrane, and manufacturing development

• Demonstrated feasibility for manual/small batch processes

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Pathways for 10X Catalyst Loading Reduction

3M NSTFCore shell catalysts

Spray deposition – UConn developed process

• Several methods show promise500 hours operation at <0.1 mg/cm2 loading

Brookhaven

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Membrane Strategies

• Polymer backbone

• Branching level

• Fluorination vs. hydrocarbons

• Reinforcement

• Blending

• Synthesis method (e.g. electrospinning vs. casting)

• Tensile strength

• IEC

• Tg, creep properties

• Conductivity

• Water uptake

• Dimensional change

• F- release rate

• Elongation to break (brittleness)

Approaches to change polymer behavior

Variables Impacted

Note: Accelerated testing (pressure, voltage, temperature cycling) not well defined for electrolyzers

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1.9

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2.2

2.3

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Po

ten

tial

(V

)

Current Density (A/cm2)

Baseline MEA, 80C

Thin membrane, 80C

12% loading, 80C

17% loading, 80C

Large potential efficiency improvement

1000’s of hours demonstrated at pressure

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Electrode integration: porous transport layers

3M NSTF

Core shell catalystsCathode GDL w/w/out MPL

• Gas diffusion layer needs to contact catalyst layer effectively while providing porosity • Typically involves a microporous layer (MPL) approach

• Materials optimized for fuel cell, not electrolyzer

• Wetproofing vs. wettability, gas vs. liquid flow

• Design and manufacturing maturity needs to catch up for electrolysis

Anode GDL concept, DLR, Germany

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AEM Electrolysis: A Long Term Option?

•Could enable a new cost curve

•Need a holistic solution for the whole system• Polymers not at required performance levels yet

(especially stability) • Developing high activity catalysts for high pH

is insufficient; need a full electrode• Translation from liquid to solid electrolyte can be poor

•Processing is improving and PGM content decreasing; eliminated for oxygen• ~1000 hour lifetimes (need 50,000)

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Baseline Cathode FF

Anode FF + MEA

Labor Alkaline Baseline

Alkaline FF + MEA

Alkaline Labor

% B

asel

ine

Materials only

Materials and labor

Projected PEM progression

PEM

Projected PEM progression

PEM Alkaline

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•Membranes: higher mechanical strength when saturated; low permeation; low creep at high load• Conductivity at low humidity less of a driving factor vs fuel cells

•Catalysts: higher activity for oxygen evolution (blended alloys, novel structures); conductive supports stable to 2V

•Porous transport layers: hydrophilic gas diffusion layers with microporous layers; optimized for 2-phase flow and interface

•Manufacturing: higher speed coatings, precise layer deposition

Basic Research Needs Specific to Electrolyzers

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Need to go beyond materials discovery

• Lab to pilot scale testing is high priority but needs to be informed• Many projects to date involve isolated work on catalysts in solution• Have to consider the whole chemical system• Separations and systems engineering are also important

•Fundamental research needs to consider integration and interfaces

•Manufacturing can be its own science – understand impact of process variables

•Scale is less important than scalability – will come with markets

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Factors for commercial scale and viability (Questions 4 and 5)

Product

Not a product

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What is the timeline for electrolysis?

•Past experience implies GW-scale is possible by 2030-35

•Requires continuing development and understanding

Existing PEM Electrolysis Designs(4 active area platforms)

Future Platforms: SMR Scale

Nas

cen

t Te

chn

olo

gy

-------13 years-------

-------------------20 years-------------------

-------15 years?-------

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What about other water splitting technologies?

New technology development = 20 years

For water splitting, assume:

• 100 MW electrolyzer scale w/in 10 yrs (conservative)

• Accelerated development of anion membranes and solid oxide vs. PEM

• Direct photoelectrochemical (PEC) at 100 kW scale in 10 yrs• ~1000 m2 electrode area

• Solar thermochemical lags by 2 years

➢Need to leverage/improve/build on what we have today

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Scale up example: 20 year timeline• Each new commercial platform has had an identified market/price point

• Not likely to jump to MW/GW scale without earlier cost competitive outlets

2004-2008 H and C-series: Power Plants/Industrial

1999 Lab line: Instrumentation

2004: S-series: Weather Balloons

2014 M-series: Energy Storage and Biogas

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Siting Considerations

•H2 has handling risk but codes and standards are well established• Typical electrolyzers generate at 30 bar hydrogen• Water usage lower than SMR, no hazardous effluent• Proton/NEL has >3500 units sited on 7 continents, >80 countries• High current density enables compact footprint

•Safe system design and certification required for new technology

QatarVietnam AC Transit, EmeryvilleFreiburg, Germany

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Platform ScaleUp

AdvancedStack

Increasedcurrent

Powerelectronics

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W, 2

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co

st b

asis

PEM Cost Reduction Opportunities

Room in all major areas for significant improvement: First three require materials and process understanding

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Cost Evolution with Scale: Stack and System

• Cost curve primarily driven by material utilization

• Additional reduction possible with technology development (roadmap)• Improved bipolar plate format example

Proprietary and Confidential

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• Rule of six tenths supported by past scale up activities

Stack Balance of Plant

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Priority directions to meet targets

Near term:

• Translation of fabrication processes to pilot scale methods more representative of large scale

• Application of structure-property relationships to modify membranes and porous transport layers for optimal water splitting

• Electrode engineering for high material utilization

Medium term:

• Development of stable anion exchange materials

• Solid oxide cells with thermal cycling stability and pressurization

Long term:

• Definition of scale, limitations, and opportunities for alternative technologies

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Overall Conclusions

•Need a mix of short term and long term technology R&D for H2• 20 year solution will be dominated by next generations of existing technology• 50 year solution may transition to longer term innovations/technologies if proven

•Fundamentals of integration and manufacturing need to be a major factor in near term technology development

•Cultivate synergies between technologies: e.g. PEM electrolysis and PEC• Oxygen evolution catalysts and corrosion resistant supports• Low permeation membranes

•Gas separation and systems engineering options need to be considered

•Derivative technologies (e.g. electrochemical CO2 conversion) can also be leveraged to advance components