Advanced Alkaline Electrolysis

Richard Bourgeois, P.E.GE Global Research Center

16 May 2006

Project# PD8This presentation does not contain any proprietary or confidential information

2

Overview

Project start date 1 April 2004

Project end date 30 Dec. 2005

Percent complete 100%

Barriers addressedQ. Capital Cost of Electrolysis Systems

T. Renewable Integration

Technical Targets:2010: Electrolyzed Hydrogen @ $2.85/ kg

Total project funding M$2.1• DOE share M$1.4• Contractor share M$0.7

Funding received in FY04 M$1.05

Funding for FY05 M$0.35

Timeline

Budget

SUNY Albany Nanotech

Partners

3

Objectives• Develop a commercial strategy for low cost

alkaline electrolysis

• Demonstrate a laboratory scale proof of concept

$0.38$ / kg H2CostO&M

$1.89$ / kg H2CostElectricity (System)

$0.39$ / kg H2Cost

76% (1.6V)% ( Voltage)EfficiencyCell Stack

2010 DOE Target

Units

4

ApproachQuantify Market Requirements

Establish customer and mission profileDetermine target product size and configuration

Design SystemSet performance targets to meet customer requirementsIdentify technical barriers in development path

Electrochemical Cell AnalysisDevelop and test materials for low cost electrolyzer stackOptimize system cost, performance, and reliability

Bench Scale TestingBuild and test proof of concept system

Full Scale Installation ConceptDesign reference plant

5

Optimizing H2 Cost Drives TradeoffsVoltage / Current Tradeoffs

0

500

1000

1500

2000

2500

3000

3500

1.5 1.6 1.7 1.8 1.9 2 2.1 Cell Voltage

Cur

rent

Den

sity

, A/m

2

0

10

20

30

40

50

60

m2

to m

ake

1 kg

/hr H

2

82% 77% 72% 68% 65% 62% 59% Efficiency

Baseline IV curve

minimizes capital costs

minimizes energy costs

$1.99

$2.00

$2.01

$2.02

$2.03

$2.04

$2.05

$2.06

Cell Voltage

H2

Cos

t, $

/ kg

Total CostEnergy CostCapital Cost

Optimal Voltage

Lowest cost operating point varies with cost of electricity and specific cost of material

6

Technology Plan for Low Stack Cost

High surface area electrodes minimize stack size

Advanced materials enable low assembly costs

7

Electrode Concept Selection

1 10 100

base metals

GE electro –deposited

GE spray

precious metals

Cel

l Ove

rpot

entia

l

Relative Cost per Unit Area

TargetZone

dimensionallystabilized anode (DSA)

Wire arc lowest risk solution to meet targets:Electrodeposition next potential cost reduction

8

Proof of Concept Plastic Stack

First “true monolith” – design details per product concept

5 x 153 cm2 cells

500W input power

10 gph output

Noryl plate / epoxy construction

Wire arc Raney electrodes

Dual inlets to eliminate shunts

9

“500W” Bench Scale System

coalescing filter

thermocouple port

gas–liquid separator tanks

5-cell stack

power leads

sight tubes

pressure sensor

electrolyteheater

cellvoltage

gas exit lines

Figure 5: Bench Scale Test Stand

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1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95

Cur

rent

Den

sity

, A/m

2

Flow

Current

Cell VoltsEfficiency

Flow, slpm

79% 77% 75% 72% 70% 68% 66% 65% 63%

TARGET ZONE

Electrode C4Electrode C5

Bench Scale Test Results

• Operable across wide efficiency range• Performance meets requirements

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diaphragmanode cathode

+ Vcell–

Va

Va, rev

Vsol/dia, a Vsol/dia, a

Vsol/dia, c

Vc, rev

Vc

∆Vov, c

∆Vov, a

IRsol/dia

diaphragmanode cathode

+ Vcell–

Va

Va, rev

Vsol/dia, a Vsol/dia, a

Vsol/dia, c

Vc, rev

Vc

∆Vov, c

∆Vov, a

IRsol/dia

diaphragmanode cathode

+ Vcell–

Va

Va, rev

Vsol/dia, a Vsol/dia, a

Vsol/dia, c

Vc, rev

Vc

∆Vov, c

∆Vov, a

IRsol/dia

Computational Study of Cell Performance

O2 bubbles mask anode, increasing

overpotentialH2 bubbles mask

cathode, increasing overpotential

Bubbles displace electrolyte, lowering effective conducting

area.

• Multi-phase turbulent flow• Porous media• Electrochemical reactions• Electron/Ion transport• Dissolved species

Highly non-linear problem requiring

development of advanced models

12

Learning from Two Dimensional CFD

Electrolyte

Experimental Validation

Effect of gas coverageH2 volume fraction

Current density

Cell voltage, V

1.6 1.8 2 2.2

PredictedExperimental

i, m

A/c

m^2

Optimize Passage Height

height, mm

i, m

A/c

m^2

0 0.5 1 1.5 2

slow flowmedium flowfast flow

Simplified model /

experimental geometry

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Stack Scaleup to 1 kgph system

baseline round cell

square cell elliptical

H2 Fraction Current Density

High CD

Low CD

100% H2

0% H2H2 Fraction Current Density

High CD

Low CD

100% H2

0% H2Cathode

Anode

3D electrochemical CFD capability enables fast geometry optimization

14

Power Park Conceptual Design

(1) Refueling

(2) Electrical Generation

Conceptual Design and Functional Modeling by Dr. Stephen Sanborn, GE

15

Conceptual DesignsRendered in 2-D Drawings & 3-D “Virtual Tour”

16

Wind Speed at Albany New York1-Year, 1-Hour Scenario

0

5

10

15

20

25

30

35

40

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 1

Hour of Year

Win

d Sp

eed

(m/s

ec)

Win

d Sp

eed

(mile

s/ho

ur)

Wind Speed at Albany New York1-Year, 1-Hour Scenario

0

5

10

15

20

25

30

35

40

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 1

Hour of Year

Win

d Sp

eed

(m/s

ec)

Win

d Sp

eed

(mile

s/ho

ur)

H2 Power Park Functional Modeling

H2

Service AreaParking Lot LightsRestaurant LoadService Station LoadCCHP supplement

H2-fueled ICE

Electrolyzer

Site Electrical

Distribution

Integrated Control &

Condition Monitoring System

Potab leWater

Local Distribution& Protection

3-phaseOnto site

H2 Compression& Storage

H2 Compression& Storage

AC green

AC green

H2 DispenserH2 DispenserH2

Service AreaVehicleRefuelingDemand

24 Hour H2-Vehicle Refueling Scenario(based on H2A scenario scaled to 300 kg/day)

05

1015202530354045

0 5 10 15 20 25 30

Hourly H2 Demand(kg)

00.5

11.5

22.5

33.5

44.5

IOpti

mal_I II

Optimal_

II IIIOpti

mal_III IV

Optimal_

IV VOpti

mal_V VI

Optimal_

VI

VII

Optimal_

VII

Wind TurbineElectrolyzerH2-ICEH2-StorageCOE ($/kW)

self sustaining COE COH

System Block ModelWind Energy. Electricity and Fuel Demand Models

TRNSYS15 optimization code Result: Optimized equipment

selection for various scenarios

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Additional Work: “1 kgph” System

Opportunity for total instrumentationStudy operability & maintenance characteristics

Capabilities:• 1 kg H2 / hr production rate• High pressure operation• Automated controls• P, T, massflow, purity

measurements• Upgradeable compression /

storage capability

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Additional Work: Electrode Lifing

Multiple sample accelerated testing underway

350, 500, and 1000 mA/cm2

Nearing 40k hours with no failures

Electrode Test Apparatus

Metal Substrate

Wire Arc Surface

Metallography

19

Future Work

First phase project has ended. Continuation of work with the 1 kgph system has been proposed to DOE and is pending.

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Relevance: Provides a technical solution to the electrolysis capital cost problem.

Approach: Leverage GE expertise in advanced plastics and coating technology to dramatically reduce electrolyzer stack cost.

Progress: Demonstrated bench-scale proof of concept and scaled up to full size stack. Met efficiency target and projecting to meet 2010 cost target.

Technology Transfer:Ready to consider demonstration projects.

Proposed Future Research:System operations and reliability growth to prepare for demonstrations.

Project Summary

21

Backup Slides

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Alkaline Electrolyzer Design Basics

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

Anode (+):2OH- H2O + 2e- + ½ O2

+ _

Diaphragm Bipolar conductor

Porous Cathode Porous Anode

Single Unipolar Cell

+ _H2O2

Electricity

Multicell Bipolar Stack

catholyte passage

anolyte passageanode

separation diaphragm

cathode other side

Bipolar type half-cells

Electrolyte

Separator

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1. Zhou, Z. and Carpenter, M.A. :“Annealing AdvancedHydrogen Absorption in Nanocrystalline Pd/AuSensing Films”; Journal of Applied Physics 97,124301 (2005)2. Zhou, Z et. al: “All Optical Hydrogen Sensor BasedOn a High Alloy Content Palladium Thin Film”;Sensors and Actuators B, March 2005

Advanced H2 sensor work by Dr. Michael Carpenter, SUNY Nanotech

Publications

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Response to Reviewers’ Comments

Strengths:• Highly innovative• Use of multiple GE technical capabilities• Integrated GE team with skills and

resources to “make this real”

Rated as #PDP-10 : New York State Hi-Way Initiative

Reviewer’s Comments and Response• Scope regarding New York’s H2 infrastructure, sensors, etc. not aligned

with HFCIT goals — 2005 scope focused on electrolysis technology and scaleup.

• “Show path to achieving HFCIT targets… using standard assumptions”— H2A model analysis presented to DOE for all GE H2 program work.

• “Current demonstration is too small… 50 kW minimum— GE has built and is testing a 50 kW system, and has applied to continue the program with testing at that scale.

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1) Electricity must be available at 5 cents / kWh or lower. This requires off-peak / industrial wholesale electricity at first, and the long term requires a cheap power solution.

2) Electrolyzers can be commercially successful without “waiting for a hydrogen economy”. The right sector of the existing hydrogen market must be targeted, and demonstrations arranged with the needs of this market in mind.

3) A unified set of codes and standards for electrolytic H2 production is necessary so that a standardized packaged product may be deployed anywhere.

Critical Assumptions and Issues