Prof Nigel Brandon â€“ Imperial - Hydrogen and Fuel Cell Supergen

Professor Nigel Brandon OBE FREng

Director, Energy Futures Lab

Director, Hydrogen and Fuel Cell SUPERGEN Hub

www.h2fcsupergen.com

www.imperial.ac.uk/energyfutureslab

Recent Developments in Solid Oxide Fuel Cells

Imperial College London

- Established in 2005 to promote and stimulate multi-disciplinary energy research.

- Research income of ~ £28Mpa for energy research, 38% from industry.

- ~600 research staff and PhD students undertaking energy research.

Integrating Themes

-Energy systems engineering

-Energy policy

-Energy business

-Energy in society

The Energy Future Lab| Integrates across Science, Engineering, Policy and Business in

the energy sector

Energy Technologies

-Fuel cells

-Energy storage

-Bio-energy

-Hydrogen

-Solar

-Carbon capture and storage

-Oil and gas

-Smart grids

-Transport systems

-Nuclear fission and fusion

-Electric and hybrid vehicles

-Green aviation

Prof. Nigel Brandon – Imperial College, Dr David Book – Birmingham Univ.,

Prof. Paul Ekins – UCL, Prof. Anthony Kucernak – Imperial College, Dr Tim

Mays – Bath Univ., Prof. Ian Metcalfe – Newcastle Univ., Prof. Vladimir

Molkov – Ulster Univ., Prof. Robert Steinberger-Wilckens – Birmingham

Univ., Prof. John Irvine – St Andrews., Prof. Nilay Shah – Imperial College.

The 1st Annual Conference of the H2FC SUPERGEN Hub will

be held at All-Energy in Aberdeen on May 21st and 22nd 2013

–registration (free) for All-Energy is required for the 22nd.

Everyone is welcome to join the H2FC SUPERGEN Hub as

an Associate Member – see the website or Chloe Stockford

for details. www.h2fcsupergen.com

The Hub organises regular events, and has further funding to

award to eligible UK academic participants.

Content

• Why are Solid Oxide Fuel Cells of interest?

• SOFCs for residential scale mCHP.

• SOFCs for distributed power generation.

• Examples of current research at Imperial College.

• Summary.

So why are fuel cells of interest?

• A fuel cell is an energy conversion device - it converts

fuel and air electrochemically into electricity (and heat).

•Fuel cells have the highest known efficiency of any

energy conversion device – an efficiency which further

increases at part load.

• By avoiding combustion fuel cells produce extremely

low levels of NOx and particulates.

• Fuel cells are quiet and vibration free to allow a wide

range of siting options, and can be used in a wide

range of mass market applications.

Fuel Processing Options

Thermodynamic predictions of

the equilibrium composition for

methane fed at different

temperatures and steam-to-

carbon ratios. The combined

CH4 + H2O input amount is 1

kmol in each case.

The rise of gas in the United Kingdom

• Over the last 40 years, gas

has become a key player in

the UK energy system

• Seeded by the discovery of

gas in UKCS

• Sustained by a coal -> gas

switch in heating, and

introduction of central heating

• Consolidated by the “dash for

gas” in the 1990s for power

generation

• Rapid growth in shale gas is

also driving gas use in

global markets

The Rise of Gas in the UK Energy System (Gas

Primary Energy Consumption 1970-2011)

Source: Digest of UK Energy Statistics, 2012

IEA Golden Age of Gas Scenario

Gas Demand by Region

2010 2015 2020 2025 2030 20350

1000

2000

3000

4000

5000

6000

Time (years)

De

ma

nd

(b

cm

)

North America

Europe

Pacific

E.Europe Eurasia

Asia

Middle East

Africa

Latin America

International Energy Agency. Are we entering a golden age of gas? Special report in World Energy Outlook 2011.

IEA, Paris, France

Polymer Fuel Cells

•Focus on hydrogen as a fuel, primarily for transport applications. Potential to

de-carbonise the transport sector if hydrogen is produced from nuclear,

renewables, or with CCS.

•Toyota and Daimler have both committed to commercial launch of FCEVs in

2015 – range 700 miles at a vehicle price of $50k in volume.

•30,000 PEMFC mCHP units (0.7 kWe) sold to residential customers in Japan

from April 2011 to March 2012 (JX Nippon Oil and Energy).

Solid Oxide Fuel Cells

•Focus on natural gas for stationary systems, but has the potential to operate

on renewable fuel e.g. biogas.

•Efficiency is high on hydrocarbon fuels (>40% for ‘small’ (kWe) stand alone

systems through to 70% for ‘large’ (MWe) gas turbine hybrids).

•Over 20MWe capacity of Bloom SOFC units installed in USA.

•Over 1000 0.7 kWe mCHP units sold to consumers in Japan since launch in

October 2011. 15,000 hours operation demonstrated – sold with a 10 year

guarantee (JX Nippon Oil and Energy) at 2.5M Yen before 850k Yen subsidy –

net cost to consumer around £11k.

Content





• Summary.

Fuel

Fuel

Cell Fuel

Heat

Electrical

50%

40%

Energy

100%

Power station

55% losses

Transmission

5% losses

Delivered

40%

Fuel Cell

10% losses Delivered

90%

Energy

100%

Conventional

Micro-CHP

Fuel Cell Boilers for the Home (micro-CHP)

Micro-CHP Technologies

Baxi Stirling engine Panasonic PEMFC

Ceres Power and British Gas SOFC

Honda ECOWILL ICE

Honda ECOWILL ICE with Storage

0 4 8 12 16 20 240

2

4

6

8

10

12

14

16

Time (Hours)

Dem

and (

kW

)

Space Heating and DHW Demand

Electricity Demand

Residential heat and power demand

Heat and Power Demand over 1 Day in a Typical UK Dwelling

Economic Drivers for m-CHP Systems

• Dwelling Annual Electricity Demand •The main value driver for micro-CHP is (the ability to displace) onsite electricity demand.

•If onsite electricity demand exists, the ability to access the value available (in displacing it) is dependent on the heat-to-power ratio (HPR) and presence of thermal demand.

0 2500 5000 7500 100000

200

400

600

800

1000

1200

IC Engine

0 2500 5000 7500 100000

200

400

600

800

1000

1200

PEMFC

0 2500 5000 7500 100000

200

400

600

800

1000

1200

SOFC

0 2500 5000 7500 100000

200

400

600

800

1000

1200

Annual Electricity Demand (kWh/year)

Maxim

um

Cost

Diffe

rence B

etw

een

Mic

ro-C

HP

Syste

m a

nd B

oiler

Syste

m (

£)

Stirling Engine

Low Thermal Demand

Average Thermal Demand

High Thermal Demand

HPR = 1

HPR = 3 HPR = 2

HPR = 8

Dwelling Annual Electricity Demand

Hawkes, AD, Staffell, I, Brett, DJL, Brandon, NP, Fuel Cells for Micro-Combined Heat and Power Generation, Energy &

Environmental Science, 2009, Vol: 2, Pages: 729 - 744

5000 10000 15000 20000 25000 300000

500

1000

1500ICE

5000 10000 15000 20000 25000 300000

500

1000

1500PEMFC

5000 10000 15000 20000 25000 300000

500

1000

1500SOFC

5000 10000 15000 20000 25000 300000

500

1000

1500

Annual Thermal Demand (kWh/year)

Annual C

O2 R

eduction w

.r.t. R

efe

rence S

yste

m (

kg C

O2/y

ear)

)

Stirling

Flat

Bungalow

Terrace

Semi-Detached

Detached

Environmental Drivers for m-CHP Systems

CO2 Reduction – Thermal Demand •CO2 reduction is dependent on ability to displace grid electricity.

•Ability to displace grid electricity, and thus bring about CO2 reduction, is dependent on annual thermal demand and prime mover heat-to-power ratio.

Hawkes, AD, Staffell, I, Brett, DJL, Brandon, NP, Fuel Cells for Micro-Combined Heat and Power Generation, Energy &

Environmental Science, 2009, Vol: 2, Pages: 729 - 744

marginal CO2 intensity of UK

electricity 0.69kgCO2/kWh

Ceres Power SOFC micro-CHP unit

Reduces the energy bill of a customer by around 25% and saves around

1.5 tonnes of CO2 pa. In addition, under the UK feed in tariff (FIT), a

household installing a SOFC mCHP product will receive, for a period of ten

years, a generation payment of 10p/kWh (proposed to increase to 12.5p).

For a typical UK home with a Ceres micro-CHP unit, the annual FIT is £436,

on top of the predicted annual energy cost savings of £286.

© Ceres Power 2013 Title: 8th International Smart Hydrogen and Fuel Cell Conference Rev: 1.0

• Thin steel substrate with even

thinner layers of active SOFC

materials coated on top

• Low temperature electrolyte (ceria)

enables operation at <600 oC

• Key advantages:

– Low cost cells

– Compact, lightweight design

– Mechanically tough

– Simple & reliable stack sealing

– Enables low cost balance of plant

The core of the Ceres proposition is its unique metal-supported cell

10

Stainless Steel Substrate

Anode Layer

Ceria ElectrolyteLayer

Cathode Layer

FUEL

AIR

ELECTRICITY

Slide supplied by Dr Mark Selby, Director of Technology, Ceres Power


Enables a compact 1kW-Class Stack

12

o 93 to 140 cells

o Cell fuel side sealing by

laser weld

o Compression maintained at

operating temps; low creep

o Pre-formed high temp

gaskets

o Robust seal created on

compression

o ~50mV max voltage

variation across cells in

stack

Designed for simple manufacture and assembly

191.9mm

152.5mm

Weight - 9.3 kg

Volume - 4.1 l

141.4mm

99 cells variant

Weight - 70 g

Single cell

(Including seal)



Highly compact 1kW Fuel Cell Module (FCM)

Design Specification

Maximum electrical power 1000W DC

Minimum electrical power 300W DC

Electrical efficiency (LHV) 50%

Gas supply Natural Gas

Time to first power 2 hours

Electrical ramp rate 3 W/s

Degradation rate 0.5% / khrs

13

STACK

Fuel

Processor

Hx



CTP able to meet multiple start-stops required by real products

20

Ceres metal-supported fuel cell stacks are robust to repeat start-stops

Stack power measurements

at each cycle showing no

power loss

6 cell short stack:

Sealing, Gaskets, Manifolding,

Current collection identical to

stack used in FCMs and CHPs

56% H2/44% N2

3% H2O in Air

140 mA/cm2

Stack cycled from

operating point (590 oC)

to 100 oC

Test intentionally

stoppedRates are furnace

controlled; not

optimised

Tem

pera

ture

C

Time hrsTest Date: Dec 2011 - Jan 2012



• Emergency Stops – immediate cut-off of fuel and air with a thermal cycle

• Other fuel cell technologies can suffer catastrophic damage under this

condition

95%

Stack power measurements

showing 95% power retention

and no loss of cell integrity

Ceres stacks are robust to harshest cycling challenge possible:

Emergency Stops

7 Cell Stack

21

Test Date: August, 2012

Cells survive unplanned shutdowns (RedOx)


Content





• Summary.

2 kWe anode supported

stack at Topsoe Fuel Cells

60 kWe anode supported module from

Versa Power (4 off 15 kWe stacks)

Examples of Leading Developers

Topsoe Fuel Cells and Versa Power


Bloom Energy


LGFCS and MHI SOFC-GT Systems

LG Fuel Cell Systems IP-SOFC

MHI 200 kW SOFC-GT

Content





• Summary.

SOFC Anode Behavior, Fabrication and

Design

Illustration of the effect of extending the TPB using a MIEC electrolyte. (a)

Electrolyte / cermet anode with active TPB circled; (b) mechanism of

reaction at the TPB; (c) mechanism of reaction at the extended TPB.

Electrode Microstructure in three dimensions

TPB 2

TPB 3

TPB 1

TPB 2

TPB 3

TPB 1

Tomography of Ni-ScSZ anodes

• Allows feature extraction (Ni/ScSZ/Pores)

• FIBSEM, voxel sizes ~20-50nm

• 1350ºC sintering, 1 hr at temperature,

reduced

A

5 µm 5 µm 5 µm

Ni

30 Vol.%

Ni

40 Vol.%

Ni

50 Vol.%

Ni Ni

ScSZ ScSZ

Pores Pores

Pores

B C

Ni Percolation Threshold

Ni Percolated

Fabrication and characterization of Ni/ScSZ cermet anodes for IT-SOFCs, Somalu MR, Yufit V, Cumming D, Lorente E, Brandon NP,

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 2011, Vol:36, Pages:5557-5566.

Percolated nickel networks

• Ni30 – 65% of Ni is

percolated

A

5 µm 5 µm 5 µm

Ni

30 Vol.%

Ni

40 Vol.%

Ni

50 Vol.%

Ni Ni B C

Considered Ni

Percolation Threshold Considered Ni Percolated Considered Ni Percolated

• Ni40 – 97% of Ni is

percolated

• Ni50 – 90% of nickel is

percolated

Preliminary results indicate:

Ni 646

Pores 1317

ScSZ 1345

Ni 2481

Pores 2976

ScSZ 4195

Ni 1594

Pores 1999

ScSZ 2130

Surface Area of particles in total volume analysed (x 103 m-1)

In-situ imaging of LSCF cathode at 700C

Using Synchrotron X-Ray Nano-CT to Characterize SOFC Electrode Microstructures in Three-Dimensions at Operating Temperature

P.R. Shearing , R. Bradley , J. Gelb , S. Lee, A. Atkinson, P.J. Withers, N.P. Brandon, Electrochem. S.S. Lett. 14 (10) (2011) B117-B120.

• Size and type of carbon deposits can be determined from Raman spectra

• Carbon powders indistinguishable in white light

• Raman shows clear differences in key features allowing us to say: – Carbon A amorphous

– Carbon B highly graphitic

– Carbon C graphitic

Carbon formation studied using ex-situ Raman

1000 1500 2000 2500 3000

0

1000

2000

3000

4000

5000

6000

Inte

nsity (

arb

.)

Raman shift (cm-1)

Carbon A

Carbon B

Carbon C

The Application of Raman Spectroscopy to Solid Oxide Fuel Cells, R. C. Maher, V. Duboviks, G. J. Offer, M. Kishimoto, N. P. Brandon and L. F. Cohen,

Fuel Cells, accepted for publication.

SOFC test rig for in-situ and in-operando

Raman measurements

Brightman, E., Maher, R., Offer, G. J., Duboviks, V., Heck, C., Cohen, L. F. Brandon, N.P., Designing a miniaturised heated stage for in-situ optical measurements of SOFC electrode surfaces, and probing the oxidation of SOFC anodes using in-situ Raman spectroscopy, Rev. Sci. Instrum. 83, (2012)

Combined electrical and optical measurements critical

• 10 input/outputs in basic mode

• 2 electrode operation

• Passive cathode circulation

• 14 input/outputs in full mode

• 3 electrode operation

• Active cathode circulation

• Active air cooling of objective

• All in a 2cms (d) by 1cm (h) ‘hot zone’

• Excitation: 488, 514, 633, 780 and 830nm

• Mapping stages with 0.1µm resolution

SOFC test rig for in-situ and in-operando

Raman measurements

Brightman, E., Maher, R., Offer, G. J., Duboviks, V., Heck, C., Cohen, L. F. Brandon, N.P., Designing a miniaturised heated stage for in-situ optical measurements of SOFC electrode surfaces, and probing the oxidation of SOFC anodes using in-situ Raman spectroscopy, Rev. Sci. Instrum. 83, (2012)

In-situ & in-operando Analysis – dry CO

1200 1400 1600 1800400

500

600

700

800

Inte

nsity (

arb

.)

Early stage growth

Late stage growth

Raman shift (cm-1)

0 500 1000 1500

-20

0

20

40

60

80

100

120

140

160

Time (s)

Inte

nsity (

arb

.)

D Peak intensity

G Peak intensity

• NI-CGO anode

• 514nm, 15 sec/pt, 1.5 mm

• Pure dry CO at 600oC – Open circuit potential (OCP)

remains stable

– Initial carbon formation rapid, then plateaus

– Predominantly Graphitic Carbon

0 500 1000 1500 2000-1.20

-1.15

-1.10

-1.05

-1.00

-0.95

-0.90

-0.85

-0.80

Op

en

cir

cu

it p

ote

ntia

l (V

)

Time (s)



1200 1400 1600 1800

600

800

1000

1200

1400

1600

1800

Inte

nsity (

arb

.)

Early stage growth

Late stage growth

Raman shift (cm-1)

0 500 1000 1500

0

50

100

150

200

250

300

Inte

nsity (

arb

.)

D Peak intensity

G Peak intensity

Time (s)

• Ni-CGO anode

• 514nm, 15 sec/pt, 1.5 mm

• Dry CO & H2 at 600oC – Open circuit potential (OCP)

decays with time

– Initial carbon formation slower, but continuous

– Damage visible and profound

0 500 1000 1500 2000-1.20

-1.15

-1.10

-1.05

-1.00

-0.95

-0.90

-0.85

-0.80

Op

en

cir

cu

it p

ote

ntia

l (V

)

Time (s)

In-situ & in-operando Analysis – dry H2 -CO



Effect of current density – Ni-CGO anode

in dry CO at 600C



Summary

• SOFCs are now available commercially and are of

growing importance as a high efficiency energy

conversion devices for hydrocarbon fuels such as

natural gas and LPG.

• But to compete in the long term against other low

carbon options, and indeed to enable support in the

short to medium term, it is essential to look at lower

carbon fuel options related to the ‘decarbonisation’ of

gas.

• This sets research and technology challenges relating

to the cost effective and durable operation of SOFCs

with renewable fuel sources.

Thank you

mCHP: Adam Hawkes, Iain Staffell, Dan Brett (UCL).

Tomography and 3D structures: Farid Tariq, Khalil Rhazaoui, Sam Cooper,

Masashi Kishimoto, Guansen Cui, Prof. Claire Adjiman, Qiong Cai (Surrey),

Paul Shearing (UCL), David Eastwood, Peter Lee, Phil Withers (Manchester).

Raman and surface processes: Greg Offer, Rob Maher, Vladislav Duboviks,

Michael Parkes, Nic Harrison, Lesley Cohen, Stephen Skinner, John Kilner.

Electrode fabrication and electrochemistry: Enrique Ruiz-Trejo, Paul Boldrin,

Marina Lomberg, Vladimir Yufit, Alan Atkinson.

Integration with renewable fuels: Marcos Millan-Agorio, Elsa Agante.

Financial support from the EPSRC, EU and ONR. Synchrotron data was

collected at beam-line XOR 32-ID at the Advanced Photon Source at Argonne

National Laboratory supported by the U.S. Department of Energy, Office of

Basic Energy Sciences.

Further details on Fuel cell and hydrogen research in the UK can be found at

the Hydrogen and Fuel Cell SUPERGEN Hub www.h2fcsupergen.com

Prof Nigel Brandon â€“ Imperial - Hydrogen and Fuel Cell Supergen

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