Advanced Alkaline Electrolysis

Richard Bourgeois, P.E.GE Global Research Center

Niskayuna, NY

This presentation does not contain any proprietary or confidential information

Project #PDP16

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Acknowledgements

Acknowledgment: This material is based upon work supported by the Department of Energy under Award Number DE-FC-0706-ID14789

Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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OverviewTimelineStart: 30 September 2006End: 30 December 200820% complete

BudgetTotal Funding: $1,239,479DOE Share: $ 973,783Contractor: $ 265,696

funded by both the DOE Nuclear Hydrogen Initiative and DOE HFCIT programs

Received in 2006: $542,5462007 Funding (to date) : $ 92,478

Barriers AddressedG. Capital Cost of Electrolysis SystemsI. Grid Electricity Emissions

PartnersGE Global ResearchGE Energy NuclearEntergy NuclearNational Renewable Energy Laboratory

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ObjectivesStudy the feasibility of using alkaline electrolysis technology with current-generation nuclear power for large scale hydrogen production:

Economic Feasibility : Market study of existing industrial H2 usersTechnical Feasibility : Developing pressurized low cost electrolyzerCodes and Safety: Environmental and regulatory impact assessment

Units DOE 2012 TargetCell Efficiency % 69% (1.8V)System Cost $/kg H2 $0.70 ($400/kW)Electricity Cost $/kg H2 $2.00O&M Cost $/kg H2 $0.60

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ApproachTask 1: Define market and requirements

• Industrial users survey• Technical and pricing requirements • Nuclear regulatory and environmental impact issues

Task 2: Design and build pressurized electrolyzer stack• Develop plastic stack technology • Low cost electrode methods

Task 3: Plastics oxidation lifing• Creep resistance• Oxidation

Task 4: Demonstrate electrolyzer performance and capital costsTask 5: System operation testing

• O&M cost assessmentTask 6: Create industrial-scale system conceptual designTask 7: Create 1-kg-per-second demonstration system

conceptual design

80% complete

10% complete

5% complete

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• $ 1 BSize:Growth:

• $ 15.5 B• 10 % CAGR

• $ 17 B• 1.5 % CAGR

• >$0.5 B• 5% CAGR

• Flat Demand

• Key Use: Fertilizer

• Captive H2 Production

Facilities

• 1.5% CAGR • 5% CAGR

• >$0.5 B

Captive (90%) Merchant (10%)

• Hydrogen Used to Remove Sulfur

• EU & US Regulations Mandating Lower Sulfur Content in Gas, Diesel

• Captive H2 Production Facilities

• Hydrogen Used for High Heat Processes i.e. Plasma Spray

• Batch type process

• Manufacture of Specialty Chemicals for a Variety of Industries

• Methanol

• Hydrogenating Oils for a range of applications:

Source: HSBC, 2004

RefineriesAmmonia

ProductionMetals Fab. &

Treatment Chemical Mfr’gFood &

Personal Care

Global Hydrogen Market

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Industrial market infrastructure can lead fueling infrastructure

Distributed Industrial (250kWe – 1MWe)

Sources: Chemical Economics Handbook (SRI, 2004) US Census (2002)1

10

100

1000

10000

100000

1000000

0 50 100 150 200 250 300 350

Number of Sites (US)

Site

Cap

acity

, kg

H2/

day

Ammonia Production

Petroleum RefiningFloat

Glass

FoodHydrogenation

Electronics

Metals

BWR Water Chemistry

GeneratorCooling

Large-Scale Commercial (200 MWe electrolysis)

Industrial Hydrogen Market Segments

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$446$5,000Production$1,426$16,000Prototype

Per Nm3/h

Per kg/h

Projected CapEx, 5 kg/hr stack :

$446Production$1,426Prototype

Per Nm3/hr

Per kg/hr

GE Technology Capital Costs

At 50 kWh/kg H2 , production stack cost is $100/kW

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$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

0 1 2 3 4

Electricity Cost, Cents / kWh5 6

Hyd

roge

n C

ost p

er k

gFeedstockO&MBOP CapitalStack Capital

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

0 1 2 3 4 5 6

FeedstockO&MBOP CapitalStack Capital

Source: GE Global Research, NREL H2A Model

Projected H2 Cost with GE Electrolyzer:1000 kg/day, 30 bar pressure

Low-cost electricity still key to meeting targets.

*electricity, water

*

DOE Target $3/kg

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existing fleet - US 1995-2005

0.01.02.03.04.05.06.07.08.09.0

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Nuclear 1.72Coal 2.21

Gas 7.51Oil 8.09

Cen

ts /k

Wh

(200

5)

Source: NEI, 2006

Electricity Production Costs

Lowest cost electricity available from existing nuclearElectricity market demands set actual price

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GE Alkaline Electrolysis Technology

1 10 100

base metals

GE electro –deposited

GE spray

precious metals

Cell

Ove

rpot

entia

l

Relative Cost per Unit Area

TargetZone

dimensionallystabilized anode (DSA)

1 10 100

base metals

GE electro –deposited

GE spray

precious metals

Cell

Ove

rpot

entia

l

Relative Cost per Unit Area

TargetZone

dimensionallystabilized anode (DSA)

High Surface Electrode

1000x electrode surface: performance at 1/10 traditional electrode cost

• Wire arc electrode system• Electrodeposition

Plastic Stack• One piece stack assembly:

minimal part count • Molded passages, not

machined…

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OHH

OO

e-

H+H+

H+H+

HHHH

e-e-

e-

e-

e-e-

e-

electrolyte

O2 H2H2

OHH

current

2 H2O + ELECTRICITY → O2 + 2 H2

electrode electrode

oxygen hydrogen

waterO

HHO

HH

OO

e-

H+H+

H+H+

HHHH

e-e-

e-

e-

e-e-

e-

electrolyte

O2 H2H2

OHH

OHH

current

2 H2O + ELECTRICITY → O2 + 2 H2

electrode electrode

oxygen hydrogen

water

+ _

Diaphragm Bipolar conductor

Porous Cathode Porous Anode

Multicell Bipolar Stack

catholyte passage

anolyte passageanode

separation diaphragm

cathode other side

Bipolar type half-cells

Cathode (-):2H2O + 2e- 2OH- + H2

Anode (+):2OH- H2O + 2e- + ½ O2

Electrolysis Cell Basics

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Technical Details - Electrode

1 10 100

base metals

GE electro –deposited

GE spray

precious metals

Cell

Ove

rpot

entia

l

Relative Cost per Unit Area

TargetZone

dimensionallystabilized anode (DSA)

2004-2005 Project : Wire-arc sprayed high surface electrodes

Higher Efficency

Lower Cost

Today : Electrodeposition

1 10 100

base metals

GE electro –deposited

GE spray

precious metals

Cell

Ove

rpot

entia

l

Relative Cost per Unit Area

TargetZone

dimensionallystabilized anode (DSA)

2004-2005 Project : Wire-arc sprayed high surface electrodes

Higher Efficency

Lower Cost

Today : Electrodeposition

• Achieved target performance with hot spray technique in 2005.

• Researching electrodeposition for additional cost and performance advantage:

- Thinner bipolar plate- Eliminates warping- Coats 3D electrode surface

GE electrode technology applies a high effective surface area, nickel-based coating to the base metal bipolar plate for high performance at low cost.

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Technical Details – Electrode

CELL

Tank/ Heater

TEST SETUP

MESH ELECTRODE

•Single flow cell•Ambient pressure, 80°C

FLAT PLATE ELECTRODES

•Plastic mesh for flow distribution

• Some oxide left – leaching blocked by plastic mesh

•Cathode mesh applied•Higher coated surface area

FLAT PLATE

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1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

Current, mA/cm2 (Scale removed to protect proprietary information)

Volta

ge, V

/cel

l

Flat, Pre-depositionFlat, Post-depositionMesh, Pre-depositionMesh, Post-deposition

GOAL

Single Cell Performance

Target Current Density

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Electrode Results- First Quarter

• Test results meeting target current density for single cell.

• Additional performance margin needed: large cell and multi-cell stack voltages are typically higher than small single cell.

• Additional mV reductions possible from anode side mesh, method optimization, catalyst additives.

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Electrode Assembly

Plastic weld

Diaphragm cartridge

Diaphragm cartridge

x9

Stack end assembly (machined from molded blanks

Stack end assembly (machined from molded blanks

9 cell stack core

Plastic Stack Construction

10-cell Stack module

(shell, bolts, current straps not shown)

15 bar pressure stack under construction for 2007 test

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Resistance Wire Welding

Test plan to determine process parameters and abate risks:• wire size, current, voltage• weld spacing – in-plane and stacking of plates• weld strength – tensile and crack opening• clamping strategy• wire placement and tacking• weld closure

• Robust method to join plates for test stack

• Wire path determines weld location• Allows “blind” welds along passages• Heat management, inspection method

biggest challenges

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Welding – Experimental Setups

Coupon

Pressure Test

Full Plate with Manifolds

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Plastic Oxidation Lifing

1) Hot KOH and bubbling air at ambient pressure2) Ambient pressure electrolysis 3) high pressure O2 in reactor vessels

Approach: Exposing test samples to oxidant in three experiments:

Risk: Oxidation reduces strength of plastic over time. Electrolysis produces high-pressure oxygen and other oxidative species such as ozone.

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Peristaltic Pump

ReplenishingH2O Jug

4L of 30%KOH @ 80° CDC volts =2

DC current = 6.0

Oxidation Exposure Testing

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• 3-Point bend notched samples tested at 80C• No difference between oxygen-only and electrolyzer-exposed samples after 5 days• Continue sampling at 1 wk intervals

Fracture Toughness Test

If there is no difference in strength between oxygen-only and electrolysis exposed samples, the high pressure oxygen-only experiment is validated.

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2007: Regulatory assessmentComplete industrial market technical requirementsComplete electrolyzer stack technical developmentBuild and begin testing of 10-cell pressurized stack

2008: Conceptual design of reference plants

Future Work

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RelevanceTechnology for a sustainable hydrogen economy, built on current industrial markets with existing technology.ApproachCombine GE’s low cost electrolyzer stack technology, Entergy’s experience in nuclear electricity markets, and NREL’s economic modeling expertise to evaluate the feasibility of nuclear electricity and electrolysis for large-scale hydrogen generation.Technical Accomplishments and ProgressSegmented industrial market and estimated hydrogen costs for developed product. Completed conceptual design for prototype electrolyzer stack.Technology Transfer and CollaborationsCompleting market case and technology development for commercialization. Collaboration between electrolyzer developer and nuclear utility fosters a well-ordered approach to entering the industrial market.

Summary