Green Hydrogen for the Future Sustainable Growth … 6.pdfGreen Hydrogen for the Future Sustainable...

Green Hydrogen for the Future Sustainable

Growth of Human Beings

Kenichiro OTA

Green Hydrogen Research Center

Yokohama National University, JAPAN

CCUS and H2 International Conf.、Feb. 20th, 2020,

Belle Salle Kanda, Chiyoda, Tokyo, Japan

◆Global Warming, Carbon Cycle vs. Water Cycle

◆Green Hydrogen Energy System

◆Water Electrolysis

◆Polymer Electrolyte Fuel Cell

Green Hydrogen Research Center, Y.N.U.

4.5oC

2.0oC

1.5oC

0.0

1.0

2.0

3.0

4.0

5.0

-1.0

700 1000 1500

Year

21001900

Temp. Increase/℃

（by IPCC 4th Report(2007)

Rapid Global Warming on the Earth

Green Hydrogen Research Center, YNU

Solar energy

Low entropy

Heat radiation to the space

Disposal of produced entropy

Resources for

the human society

Human society

Global environment

Entropy production by the activity

of the mankind

Entropy production by the activity

of the global environment

Wastes from the

human society

Materials circulation

Q: 1.2x1014kW

ΔS=4.7 x 1011 kJ/K･s

The earth is a closed system.

Global entropy flow for sustainable growth

Green Hydrogen Research Center, YNUCarbon cycle on the earth

Sin

kin

g

flow

Atmposphere750 (360ppm CO2) (Annual increase 3.2)

Land

Vegetation 610

Soils and detritus 1580

Ocean surface 1020

Marine biota

3

Intermediate and

deep ocean

38100

Surface sediment

150

Cha

ng

ing la

nd-u

se1.6

0.5

Respira

tion

decom

positio

n

60

Photo

synth

esis

61.4

5.5

Em

issio

n

from

the s

ea

surfa

ce

90

Absorp

tion

to th

e s

ea

surfa

ce

92

6

Remains

Excrement

4

60.2

Upw

ellin

g

flow

100 91.6

□ : Carbon storage quantity. Gt Carbon

→ : Movement. Gt Carbon/year

Human activity

Fossil fuels

12000

Resp

iratio

n

deco

mp

ositio

n

50

Photo

-

synth

esis

40

Dissolved

organic carbon

700


□ ; Water storage quantity. Tt water

→ ; Movement. Tt water/year

Land

Vegetation.

Snow, ice 43,400

Surface water 360

Groundwater 15,300

Marine 1,400,000

Rain

fall

110.4

Reduced water

43.8

Marine atmosphere 11Land atmosphere 4.5Vapor transport

43.8

Evapora

tion 66.6 453.4

Rain

fall

409.6

Evapora

tion

Water cycle on the earth


Solar Energy

Low Entropy

Disposal of Entropy

To Universe

Human Society

Earth

Entropy Production by Human Activity

Natural Entropy ProductionH2O→H2+1/2O2

H2+1/2O2 → H2O

Water Circulation

H2 H2O Heat

Hydrogen Economy and Water Circulation


carbon water

Total amount 54Tt 1,460,000Tt

Atmosphere abundance 750Gt 15.5Tt

Annual movement from atmosphere

152Gt/yr 496Tt/yr

Average retention period in atmosphere

5 yaer 10 day

27000 Times

21Times

3160 Times

Comparison between water cycle and carbon cycle

180 Times


Earth Japan

Natural Carbon Cycle 150Gt/y 0.37Gt/y

Carbon (CO2) Emission

by Energy Consumption

5.5Gt/y 0.32Gt/y

EIF of Carbon 0.036 0.86

Environmental Impact Factor of Carbon

Carbon (CO2) Emission by Energy Consumption

/ Natural Carbon Circulation

EIF (Environmental Impact Factor) of Carbon

D.S.Shimel; Terrestrial ecosystems and the carbon cycle, global change biology(1995)

Green Hydrogen Research Center, YNUEIF of H2 Energy

= (H2O through H2 Energy System) / (Natural Water Vaporization)

Earth Japan

Annual

Vaporizaiton

5×1014t /y 2.3×1011t/y

H2O through H2

Energy System

5×1010 t/y 1.4×109t/y

EIF of H2 ～0.0001 0.006

EIF (Environmental Impact Factor of Hydrogen


Dependence of EIF on Consumption Density (2004-2013）

Energy Consumption Density [MJ/m2]

1

10 100 1000

0.0001

0.001

0.01

0.1

10

100

Fossil Fuel

Green Hydrogen

0.036

To

kyo

Osa

ka

Kan

ag

aw

a

Aic

hi

Sa

ita

ma

Fu

ku

oka

Hyo

go

Sh

izu

oka

Ya

ma

gu

ch

i

Sa

ga

Ish

ikaw

a

Ku

ma

moto

Gifu

Ko

ch

i

Hokka

ido

En

viro

me

nta

lIm

pa

ct F

acto

r [-

]

Iba

ragi

CO2 from Energy Usage

EIF(Fossil Fuel)= ---------------------------------

CO2 of Natural Circulation

H2O from Energy Usage

EIF(H2)= ---------------------------------

H2O of Natural Circulation


Green Hydrogen Energy System

Nuclear energy

Renewable energy

Thermal energy Power

Fossil fuel

Electric energy HydrogenFuel cell

Water electrolysis

Green Hydrogen: Hydrogen from water using renewable energy.


Future of Primary Energy

Fossil EnergyLimited resources: ultra high efficiency for use

Nuclear EnergyAgainst earth quake and tsunami

Waste treatment

Safety science for nuclear usage

Renewable energyHydroelectric power

Photovoltaic power

Biomass energy

Geothermal energy

Wind power


➢Storage of Electricity◆Mechanical storage ( compressed gas, fly wheel)

◆SMES

◆Capacitor

◆Battery

◆Hydrogen (or chemical)gas, liquid, metal hydride, organic hydride

◆Pumped hydro

➢Long distance transport of electricity◆ Liquid hydrogen

◆ Organic hydrogen (Toluene/MCH system)

Storage and Transport of Renewable Energies

Comparison of storage system of electric power

Storage Time

GW

MW

kW

W

sec min hour day month

Po

wer

Capacitor

Battery

SMES

Pumped Hydro

Hydrogen


（NEDO report)

Cost of power generation in Japan

Biomass Wind

[yen/kWh]

Cost

Solar cell Small hydro Geothermal LNG Power

Cost

Cost of wind power

[yen/kWh]

Cost

Land LandOff shore Off shore

World Japan


Hydrogen from water

・Water electrolysis : Electricity from renewable energy .

Alkaline Water Electrolysis

Polymer Electrolyte Water Electrolysis.

High Temperature Water Vapor Electrolysis.

.

・Thermochemical process : Heat (1000 oC or lower ) of HTGR, solar heat etc.

Multi-step chemical reaction

・Direct thermal decomposition : High temperature over 4000 oC.

Separation at temperature.

・Photo decomposition : Photo-chemical reaction

Complete decomposition using visible light is still impossible.

Hydrogen production method


1.4

1.5

1.6

1.7

1.8

1.9

0 0.1 0.2 0.3 0.4 0.5

電流密度　/　Ａcｍ-2

セル電圧　/　

Ｖ

固体高分子型

アルカリ型

Characteristics of Water Electroysis

Alkaline Electrolyzer

Commercially available

Cheap (Fe or Ni Electrode)

Polymer Electrolyte Electrolysis

High Density, High Efficiency

Expensive (Pt or Ir base)

Cell

Voltage

Current Density

Alkaline Type

Polymer Electrolyte Type

50 ℃


Polarization of Pt in Aqueous Solution

1M H2SO4

1M KOH

E vs. RHE / V

i/ m

A c

m2

Theoretical

Potential of HER

Theoretical

Potential of OER

-50

-25

0

25

50

0 0.5 1.0 1.5 2.0

Critical Issue of water Electrolysis

large oxygen over potential

＝＞ Voltage loss

A New Electrode Material is needed.


Commercial Alkaline Water Electrolyzers in 1970s

Company

Method

Pressure(kg/cm2)

Temp.(℃)

Electrolyte(KOH, %)

Current Density(A/m2)

Cell Voltage(V)

Current Efficiency(%)Power Consumption

(kWh/Nm３H2)

>99.9

4.9

Monopolar

normal

70

28

1,340

1.9

>99.9

4.9

Bipolar

normal

80

25

2,000

2.04

>98

4.9

Bipolar

normal

80

25

1,750

1.75

98.5

4.6

Bipolar

normal

80

29

1,500

1.9

98.75

4.5

Bipolar

30

90

25

2,000

1.86

Stuart Energy （Electrolyzer） ABB(BBC） Norsk Hydro De Nora IHT(Lurgi）

Target： From 5 kWh/Nm3H2 to 4 kWh/Nm3H2


H2(g) + 1/2O2(g)

Total Energy

ΔHo

286 kJ/mol

[242 kJ/mol]

Electrical Energy

ΔGo

237 kJ/mol

[229 kJ/mol]

Heat

TΔSo

H2O(l), [H2O(g)]

Fu

el C

ell

Wate

r E

lectr

oly

sis

49 kJ/mol

[13 kJ/mol]

Energy change of water formation reaction(25oC)


0

100

200

300

0

0.5

1

1.5

0 500 1000100

Temp./ oC

En

erg

y/k

J m

ol-

1

Total Energy (ΔH)

Vo

lta

ge

/V

Electic Energy(ΔG）

Gas

Heat(TΔS)

Liq.

H2 + 1/2O2 = H2O

Theoretical Voltage of Fuel

Cell and Water Electrolysis

Low Temp. > High Temp.

Temperature Dependence of Water Formation Reaction


Theoretical Efficiency of Fuel Cell vs Carnot Efficiency

100

80

60

40

20

0200 500 1000 1500 2000

Effcie

ncy

/ %

Temp. / K

Carnot Eff,: C

Fuel Cell: F

εF = ΔG(T)／ΔHo(298)(HHV)

εＣ＝（ＴＨ－ＴＬ）／ＴＨ

Fuel Cells

PEFC: Room Temp.～120℃AFC:Room Temp.～200℃PAFC:120～200℃MCFC:600～650℃SOFC:600～800℃


Characteristics

⚫ High power density

⚫ Low operation temperature

Applications

⚫Co-generation system (CHP)

⚫ Fuel Cell Vehicle

⚫Mobile power source

Major technical issues

⚫ Cost down

⚫Improvement of performance

Polymer Electrolyte Fuel Cell (PEFC)

H2 H+

O2

H2O

O2 gasH2 gas

O2+H2OH2

e-

e-

cathode

anode

polymer electrolyte 23


(2005.7.09 - )

1 kW home cogeneration system

The commercialization started in 2009.

Over 300,000 units are operating in Japan.

Capacity

1 kW – 700 W

Hot water (60oC, 200 L)

Daily Start and Stop

without N2 purge

(Hot water oriented mode)

Life > 10 years

The cost target: 7,000 US$/unit in 2020.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

2005/8/25 0

:00

2005/8/25 2

:00

2005/8/25 4

:00

2005/8/25 6

:00

2005/8/25 8

:00

2005/8/25 1

0:0

0

2005/8/25 1

2:0

0

2005/8/25 1

4:0

0

2005/8/25 1

6:0

0

2005/8/25 1

8:0

0

2005/8/25 2

0:0

0

2005/8/25 2

2:0

0

Month CO2

Reduction

kg-CO2

CO2

Reduction

%

Jan 17.5 11.5

Feb 38.3 21.6

Mar 41.8 21.9

1 kW PEFC at my home

24

Green Hydrogen Research Center, YNUFCVs in Japan

Compressed H2 gas ( 70 MPa)Driving Range > 650 kmLife > 10 years (5000 h)Cold start at - 30oCOutput Power: 3 – 3.5 kW/L

NEDO’s new target is 9 kW/L

in 2040.

Commercialization has started in 2014. Target 200,000 FCVs with 320 H2 Stations in 2025.


0 10 20 30 40 50 60 7015

25

20

E/V

H2-O2

25% H2SO4

39 st acks ( 100cm2x39)44. 2℃

30

I /A

1st Hydrogen Fuel Cell Vehicle in Japan (1988)

1.1 kW, H2/O2-100cm2x39 cells

Sulfuric Acid Type

Speed: 30 km/h

S. Motoo, R. Hirasawa, K. Ota, R. Furuya (Yamanashi Univ., Univ. of Tokyo, Yokohama Nat. Univ.) 26

Green Hydrogen Research Center, YNUProblems of Pt catalyst

965 million (in the world)

Instability of Pt cathode

Resources of PtHigh cost and limited ! !

100 kW FCV

→50 g Pt !!

39000 ton(2006)

800 million

Number of motor vehicles (2009)

Pt resources

Limit of reduction for Pt usage!

Problems of cathode catalyst

27

Green Hydrogen Research Center, YNUConcept of Non Pt Cathode for PEFCs

High stability

High catalytic

activityCombined

Group 4 and 5 metal oxides are stable in acid and O2 .

Development of innovative materials.

28


By Toppan Printing

Operation condition

Temp. : 80℃R. H. : 100

Membrane : Nafion211

H2/O2 = 0.2/0.3 MPa-G

Loading : 10 mg/cm2

Current density / A cm-2

Cell

voltage

/ V

Zr oxide-based cathode

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 0.5 1.0 1.5

IR corrected

Single cell performance

1.2 A cm-2 @ 0.6 V (IR corrected)

2008 2010 2012 2014 201610-3

10-2

10-1

100

101

Year

TiZrTa

@ 0.6 V

H2/O2 = 0.2/0.3 MPa-G

Cu

rre

ntdensity @

0.6

V / A

cm

-2

IR included

Cell performance increased drastically.

29


30

PEFC for Future Generation

➢More Stable Fuel Cell

➢More Efficient Fuel Cell

Operating voltage: ~ 0.9 V

Energy Efficiency: ~ 60 %(HHV)

Operating temperature : 120 oC or higher

Our target: NPGM Catalyst without Carbon.


Zr-CNO /

MWCNT_30oC

TixNbyOz+

Ti4O7_30oC

Fig. Potential-ORR current curves of

TixNbyOz+Ti4O7 and Zr-CNO/MWCNT.

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0

0.2

0.6 0.8 1.0 1.2

E vs. RHE / V

i OR

R/ m

A g

-1

TixNbyOz+

Ti4O7_80oC

Onset potential=1.15 V

High onset potential

High quality of active point.

More than Pt ?

Onset potential of oxide cathode

31


1.0

1.1

1.2

Cycle /-

Eo

nse

t/

V v

s.

RH

E

80 oC

30 oC

1.2

Start-stop

cycle test

0 10000 200005000 15000

80 oC

30 oC

1.0

1.1

Load cycle

test

Onset Potential during the potential Cycle

Fig. Onset potentials of TixNbxOz supported by Ti4O7.

Eonset ~ - 20 nA/cm2, Ti:Nb = 85:15

No change during cycles.

Active points are stable.

32

Green Hydrogen Research Center, YNUAcknowledgment

The author thanks to the members of NPGM oxide cathode

project for their help and the New Energy and Industrial

Technology Development Organization (NEDO) of Japan for

the financial support.

33


Green Hydrogen -

Key For the Future Sustainable Growth

Thank you for your kind attention!!34

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