stack performances in high temperature steam electrolysis and co- · pdf file ·...

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Stack performances in High temperature steam

electrolysis and co-electrolysis

J. Mougin, M. Reytier, S. Di Iorio, A. Chatroux, M. Petitjean, J. Cren, J. Aicart, M. De Saint Jean

Hydrogen Components and Systems ServiceCEA-LITEN, Grenoble, France

Whec2014, Gwangju, Korea, 18 June 2014

OUTLINE

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Introduction

Presentation of the technology

Development strategy

Some specificities

ResultsHigh temperature steam electrolysisCo-electrolysis

Cost analysis:System manufacturing cost and selling priceLevelized cost of hydrogen

Conclusions


INTRODUCTION

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Why Water Electrolysis to produce H 2?To produce H2 with low carbon footprintPrinciple:

H2 production = proportional to the intensity of electric currentIncrease of current density (A/cm²) � compacity � decrease of investment costEfficiency (kWh/Nm3) = inversely proportional to the voltage

0.6

0.8

1

1.2

1.4

1.6

1.8

-3 -2.5 -2 -1.5 -1 -0.5 0

i (A/cm²)

E (

V)

1.34 0.450.90 0.230.681.12

H2 production (L/h/cm²)

To date: Most mature technology: technology using alkaline electrolyte Technologies using polymer electrolyte upon advanced development For both technologies 80 % of the price of kg H2 produced due to the price of electrical energy


<800°C

�H = �G + T�SH2O → H2 + ½ O2

Energy gain with gas phases

∆H almost constant~ 250 kJ/mol

∆G decreasesT∆S increases

T∆S : waste heat � low cost

Increasing temperature:- Decrease of electricity demand thanks to thermodynamics - Improved electrochemical kinetics But limitations due to materials

Source: Chase NIST-JANAF Thermochemical Tables (1998) Monograph 9, 1325

�H : total energy

�G : electrical energy

Q=T�S : Heat

0 200 400 600 800 10000

1

2

3

Energ

y (

kW

h /

Nm

3of

H2)

Temperature (°C)

Gas

Liq

uid

INTRODUCTION

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Why High temperature Steam Electrolysis (HTSE)?


INTRODUCTION

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Electrolysis efficiency:Comparison of operating points of alkaline, PEM and High Temperature Steam electrolysis

U (

V)

-0,5-2 -1-1,5

HTSE

i (A/cm²)

0

0,5

1

1,5

2PEMWE ALKALINE

H2 production (Nm3/h)

A better efficiency :- low T electrolysis : 4 to 6 kWh/Nm3

- high temperature electrolysis< 3,5 kWh/Nm3

Less sensitive to the price of electricity (but higher cost for initial investment)

A better efficiency :- low T electrolysis : 4 to 6 kWh/Nm3

- high temperature electrolysis< 3,5 kWh/Nm3

Less sensitive to the price of electricity (but higher cost for initial investment)


PRESENTATION OF THE HTSE TECHNOLOGY

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Stack = assembly of several cells:Complex assembly of:

- brittle ceramics (cells=anode/electrolyte/cathode)- And rigid mechanical components (interconnects)

gastightness to be achieved and maintained with timehigh temperature: 700-800°C


Maximum Hydrogen production and efficiency (kWh/Nm3)Cells quality + No losses due to stacking and systemRobustness (start-up and shut-

down), reliability and reproducibility

Compactness (cells quality)“low weight” and simple stack Solutions able to be scaled up in industrial way

Cells qualityNo losses due to stacking (protective coatings, …)Optimization of operating parameters

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PRESENTATION OF THE HTSE TECHNOLOGY

Key parameters for the technology


Low-weightstack design

Co-electrolysisCO2/H2O

Power to gas, Power to liquid

Hydrogenproduction

(Industry, énergy)

Refuellingstation,…

ElectricityProduction

StationaryCHP

SOEC/SOFCreversible

Renewableenergiesstorage

| Whec2014, Gwangju, Korea, 18 June 2014

�

�

Coretechnology

Stack

PRESENTATION OF THE HTSE TECHNOLOGY:SOME SPECIFICITIES

800°C, 90%H2O/10%H2 on the hydrogen

side, air or O2 on the oxygen side,

SC=45% for i = -1.6 A/cm²

Good performance - 1.6 A/cm² at 1.2-1.3 VFor the 3 stack scales⇒ stack upscalingvalidated1.7 Nm3/h of H 2 producedfor the 25-cell stack

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HTSE:PERFORMANCE RESULTS

3-cell, 10-cell and 25-cell stacks




SC=45% for i = -1.6 A/cm²

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Very low scattering between different cells100% gas tightness⇒ Design of low-weight stack validated

3-cell, 10-cell and 25-cell stacks




SC=37% for i = -1.8 A/cm²

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Focus on 25-cell stack


Good performance - 1.8 A/cm² at 1.2-1.3 VWhen flow rate increasedPower consumed by the stack = 5.6 kWTo produce 1.88 Nm 3/h H2

Efficiency = 3 kWh/Nm 3

800°C, different compositions on the

hydrogen side, O2 on the oxygen side,

SC=52% for i = -0.8 A/cm²

Good performance Performances close to those measured in steam electrolysis (even for inlet gas composition 45 vol.% H 2O + 45 vol.% CO 2 + 10 vol.%H 2)-0.8 A/cm² at 1.15 V

with a conversion rate of 52% (0.92 kW)

100% of gas recovery at the outletH2+CO production: 0.34 Nm 3/h

at 80 AO2 production: 0.17 Nm 3/h at

80 A

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CO-ELECTROLYSIS:PERFORMANCE RESULTS

10-cell and 25-cell stacks


8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

13

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

current (A)

sta

ck p

ote

nti

al

(V)

-64 -54 -44 -34 -24 -14 -4

conversion (%)

Ustack-90vol.%H2O-10%H2

Ustack-65vol.%H20-25%CO2-10% H2

Ustack-45vol.%H20-45%CO2-10%H2

10-cell stack in electrolysis and

co-electrolysis mode - 800°C

8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

13

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

current (A)

sta

ck p

ote

nti

al

(V)

-64 -54 -44 -34 -24 -14 -4

conversion (%)






Good performance Same conclusions for 25-cell stack

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CO-ELECTROLYSIS:PERFORMANCE RESULTS

10-cell and 25-cell stacks


8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

13

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

current (A)

sta

ck p

ote

nti

al

(V)

-64 -54 -44 -34 -24 -14 -4

conversion (%)






8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

13

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

current (A)

sta

ck p

ote

nti

al

(V)

-64 -54 -44 -34 -24 -14 -4

conversion (%)





co-electrolysis mode - 800°C-64 -54 -44 -34 -24 -14 -4

18

20

22

24

26

28

30

32

34

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

conversion (%)

sta

ck p

ote

nti

al

(V)

current (A)






-64 -54 -44 -34 -24 -14 -4

18

20

22

24

26

28

30

32

34

-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

conversion (%)

sta

ck p

ote

nti

al

(V)

current (A)






Good agreement between experiment and simulation⇒ Predictive in-house model at stack level

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CO-ELECTROLYSIS:OUTLET GAS COMPOSITION

Measurements of the outlet gas composition and comparison to in-house modelling results

Example for the 10-cell stack


800°C, Cathodic inlet: 65 vol.% H2O + 25 vol.% CO2 +

10 vol.% H2 - Conversion rate of oxidized species =

64% at -1 A/cm², i.e. -100 A.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-160 -140 -120 -100 -80 -60 -40 -20 0

current (A)

pa

rtia

l p

ress

ure

at

the

ou

tle

t (µ

GC

) (-

)

P_H2simulation

P_CO2sim.

P_COsim.

PH2_experimental

PCO2_exp.

PCO_exp.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-160 -140 -120 -100 -80 -60 -40 -20 0

current (A)

pa

rtia

l p

ress

ure

at

the

ou

tle

t (µ

GC

) (-

)

P_H2simulation

P_CO2sim.

P_COsim.

PH2_experimental

PCO2_exp.

PCO_exp.

Selling price = 11.2 k€/Nm 3/hClose to PEMHigher than alkaline technology in terms of CAPEX, but…

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COST ANALYSISMANUFACTURING COST / PRICE OF THE SYSTEM

Hypothesis for the studySOEC system coupled with heat source for steam gene rationH2 Production capacity = 100 kgH 2/dayOperating point: 13 bars

Manufacturing cost of the system determined with:Analytical assessment of the stack costing for 100 systems/year, 30% margin and 20% contingencyActivity based costing methodology


LCOH with HTSE always cheaper than PEMWEBecomes similar to alkaline for electricity price > 100 €/MWh(European average = 123 €/MWh)

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COST ANALYSISLEVELIZED COST OF HYDROGEN

Levelized cost of hydrogen (LCOH)Expected to be lower thanks to high electrical effi ciency, which is 20-30% higher than for low T electrolysis: 3.6 kWh/Nm 3 at system level

Hypothesis of the studyCalculated with discount rate of 10% and operating time of 20 years (with replacement frequency of 3 years for SOEC sys tem), and additional surfaces to compensate performance losses over timeComparison to PEMWE and alkaline:

- No additional surface taken into account- Replacement frequency: 10 years for alkaline, 6 yea rs for PEMWE

Whec2014, Gwangju, Korea, 18 June 2014Evolution of LCOH versus electricity price

Compairons of HTSE, PEMWE and alkaline

CONCLUSIONS

Performing low-weight and low-cost stack design develop edValidated at several scales, including upscaling

High performances obtained in HTSE mode- 1.6 to – 1.8 A/cm² at 1.2-1.3V100% of hydrogen recovery at the outlet

Stack also able to be operated in co-electrolysis modeGood performance obtained for different H2O/CO2 inlet compositionsClose to pure steam electrolysis one Outlet gas composition measured, found as expected and as calculatedwith our in-house model

Cost analysis:HTSE manufacturing cost and selling price: ~ PEMWE, and abovealkalineBut high efficiency prevails over high investment costLeading to a levelized cost of hydrogen: < PEMWE whatever the electricity price, < alkaline for reasonable electricity price (100 €/MWh)

| Whec2014, Gwangju, Korea, 18 June 2014

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Thank you for your attention


Acknowledgments to:T. Donnier-Maréchal P. Szynal, M. Planque, B. Oresic at CEA

and Hygrogen Joint Undertaking (FCH-JU-2013-1)/ 621 173

for support for the HTSE developmentsKIC InnoEnergy (MINERVE project) for support of the co-electrolysis works

stack performances in high temperature steam electrolysis and co- · pdf file ·...

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