The emergence of viable solid oxide he1 cell technology In the rush to develop fuel cells in the I!WOs, the planar solid oxide fuel cell (SOFC) was generally overlooked, and considered to have limited commercial viability. In the past 18 months, there have been notable breakthrough improvements in SOFC technology, and Global Thermoelectric in Canada is working to leverage these advances to take advantage of some of the inherent advantages of the SOFC technology by developing products for the home cogeneration, light industrial and automotive sectors.
The
principal
elevated
source
Global
Recent
advances
technology potential utilise inherent of SOFC *
have
in opened
applications some
of
solid up
a new
which the
will
significant
in the technology. technology
oxide
The main
fuel
l
cell
range
of
be able
to
advantages advantages
include:
SOFC systems have the potential to achieve higher base efficiencies than other fuel cell systems.
l
SOFCs are very well suited for combined heat and power (CHP) applications, because of the availability of high-grade heat which boosts overall efficiencies up to 85%. SOFC systems can be easily adapted to operate with hydrocarbon fuels such as natural gas, propane and gasoline utilising low-cost reformers. Until an alternative fuels infrastructure becomes widespread, fuel cells such as SOFCs have a greater potential to be introduced earlier into commercial markets.
at which
is working
advantages
of planar
developing
products
automotive from
of
Calgary,
the
inherent
SOFC
technology
by
stationary
and
for
complete
for
stationary
considered
power
cycling.
temperature
SOFC
sealing
advances
have
auxiliary automobiles,
SOFC
substantially
issues and improved capability.
their
These
recent
up possibilities
systems
for low-
in the mass markets
of
unit
power and
residential
have
opened
cost, small-scale
in lower-
and planar
methods
cycling
difficulties
advances
materials
the corrosion
for large
of issues with
and
Recent
has
only
because
corrosion
rhermal
have been
technology
viable
plants,
high-temperature
thermal
the
of
Although
technology
years,
been
of the
to the design systems.
of SOFC
recognised
SOFC aspects,
microstructure through
generating
the advantages generally
Global’s
all development
ceramic
power
reduced
both
applications. covers
the core
stack
Inc
is the
operate.
to leverage
fuel cell membranes
with
SOFCs
Theromelectric
Canada
programme
Advantages of SOFCs
of these advantages
temperature
for
applications cogeneration systems
use and off-grid
for
applications.
Basic cell technology A planar
solid
oxide
fuel cell, like all fuel cells,
consists of three main components: cathode
and
reaction
is based on oxygen
from
the electrolyte.
the cathode
anode where
through
it combines
water, and with carbon dioxide
(Figure
simple
operation
hydrogen
Global 2: March 19%
from
Global planar high
w
based
hydrogen
monoxide
to create carbon is critical fuels,
monoxide
to
since
are the main anode-supported
the intent
at relatively
of GOO-75O”C.[‘] on
to the to create
fuel reforming.
cells with
temperatures are
with
has been developing density
transfer
the electrolyte
on hydrocarbon
catalytic
SOFC power
fundamental
ion (02-)
1). This dual reaction
and carbon
outputs
the anode, the
The
anodes
consisting
of achieving low operating Global’s of
cells nickel
Fuel Cells Bulletin No. 26
ferritic
stainless
perovskite anode
steel interconnect
cathode contact
degradation typical
contact
material. using
power
nickel
Extrapolating
a second-order
degradation
of operation
is 2.2%
0.53%
per
1000
(Figure
4). Work
5000
is ongoing
as residential
come
h
and efficiency
to
and are well
h of operation reduce
In
home
SOFCstacks stack development
cell designs. plate
The
brazed
common to
assembly
supported film
zirconia
(YSZ).
structure
allows
YSZ electrolyte
(5-10
improved
pm), with cathode
lanthanam
strontium
manganate
company
significant design.
is
(LSM)
improvements
on
material.
continuing
to
in the basic
tested
hydrogen
(3%
using
slightly
H,O)
on
realise fuel cell
humidified
machined
ferritic
systems.
weight,
acquired
from
research
centre
and
developed
using
technology
the Forschungszentrum in Germany,
manufacturing
Jiilich
has been improved
using
high-volume
processes.
tape-casting
printing
the basic SOFC
cell
for
the anode
and
screen-
and cathode.
Global
1 MW
of
10 MW
per
year.
power
it reduces
SOFC
system metal
stainless
can be used for the stack
steels)
balance-of-plant long-term reduced. of
SOFCs
alloys
(BOP).
Equally
degradation Global
rates
through operation.
alternative
ferritic
Areas
interconnect/cathode interconnect/anode
interface.
at 75O”C,
370
utilisation
and
air
Bulletin
testing
25%
No.26
Typically, mA/cm’, utilisation,
and
in June 2000,
the complete
system
manner
to
(Figure
meet
the
requirements
to replace having to
will
Distributed
power
products
generation
tested Enbridge
Markets
power
fuel cell production
remote
Inc, and with
is sufficient
and ready
to produce
power
Initially, Global’s
and home units
will
Canadian
telecommunications
companies
such
US. Subsequently,
a second
in Canada round
be ally,
oil and gas producers
for
opportunities
are very significant.
pilot
with
of
residential
applications.
extensively
of
excess
markets.
for off-grid
cogeneration
Overview of SOFC stationary applications
Global’s
test,
1.35 kW in
of this system
be operational
prototypes
system for
baseload
Global
prototype
provided
operated
in many
In 2001, plant
5).
recent
is on systems
To date,
gas-fueled
most
output
and
and the
of field
tests
3 20
1 .oo 0.90
0.80
$i
P_ 0.80 k% J! 0.70 P
0.60
2 'E
0.40
0" ;
0.20
a6
=
0.00
0.20
0.40
0.60
0.80 Current
-600-v
-k-
the the cell
-800-P
-750-P
where
The
completed
h. The
in a modular
the
50%
systems.
and
focus
to 25 kW
gas as the fuel. natural
to be
of savings
initial
of 1 kW
1100
arranged
include
alloys,
Stacks
residential
of complicated
Thermoelectric’s
two
makes range of
0.50
under
of study steel
the absence
natural
and
are expected
0.60
degradation
interface
is operated
and
are substantially
single-cell stainless
as ferritic importantly,
has been addressing
steady-state
Fuel Cells
(such
using
for
cycles.
fuel reformers.
to
are generally
u)
as
costs, since
less expensive
thermal
with
expensive
has operated
which
as a result
associated
provide flexibility to the system layout and to allow for monitoring the condition of each
at
is desirable
production
and numerous
to produce
Global
lightweight
power
in a wide
systems
are
to reach
cogeneration,
including
SOFC
the development
the
suitability
sectors,
and
in late 2000.
at low temperature
and
excellent
and
of
competitive
power
a
Production
per year will commence
High
thin
gives
cell
absence
heat
ie. the rate at
1.10
is building a 32,000 ft* (2970 m2) automated cell production facility in Calgary with capacity
The
the
80%,
have a high base efficiency
peak
SOFC
Cells are manufactured
for the electrolyte
stack is a proprietary
between
interconnects. transients
is
One of the unique
and SOFCs
into electrical
the
potentially
less costly
compression seal. This allows and cool-downs, and reduces
stresses
disassemble
size and cost of fuel cell
Since 1337,
SOFC
in
applications.
stack
and
industrial
are expected
of approximately
market
gas manifolding
They
Even
stamped higher
module and, if required, the freedom individual modules rather than
stainless steel plates. Changes in cell composition and design have resulted in significantly improved power densities (Table l), which will lead to lower
thermal construction
Its cell sizes of 10 x 10 cm and 5 x 5 cm
are baseline
of Global’s
high-temperature for fast heat-ups
electrolyteis based
Integrated
in the stack design.
features
operating
for
suited.
heat.
are lightweight,
allowing
well
them
products,
electrical
can be used (‘cogeneration’),
SOFCs
- the
the electrical
small-scale
fuel is converted
from
a low-cost
assemblies
thin,
density.
included
provides
lower
Global’s
cells.
The
at
which
compared
supported
power
anode-
for the use of a thin-
performance
temperatures
The
and
a multi-
both
both
which
steel, and are designed
become The
utilise
than
over competing
and where
efficiencies
10 x 10 cm
manufactured
stainless
ultimately
durable
features
interconnects
ferritic
component.
yttria-stabilised
very
earlier
of the fuel cell system are desired.
applications outputs
Global’s
advantages suited where
heat output
rate.
to fruition
be as large as -
transportation markets. Given recent technical advances, SOFCs are now expected to have cost
the
may
could
power 1000
to further
cogeneration
and
trend,
over the first
a
as the
per 1000 h, but reduces
h after
this degradation
is used with
and
750 - v
1.00 Density,
-700-v --‘--700
P
1.20
1.40
1.60
1.80
A/cm’ --3+650-V
-600-V
-=-650-P
-A-600-P
fuel a
CJ
ensure
acceptable
within
the
then added 375
N E 2
350
325 300 275
0
100
200
300
400
Elapsed
500
Time,
600
700
to the warm
natural
to provide
for
pre-reformer.
In
and thermal
energy
the
stack
output
steam
reforming
catalyst.
The
225
suited
for
involving
a larger
variety
quantity
of applications
Remote
power
markets,
or where
costly, will
probably
These
the
is
power
is
;lobal
fuel cell products
company’s
remote
allow
successfully
grid grid
the
will
thermoelectric
used primarily
and
should
power
itationary product levelopment
be the first users of Global’s
products,
protection
where
obtaining
fuel cell sysrems.121 generator
and a wider
will take place in 2002.
unreliable
complement
of units
instrumentation,
for multi-kW
projects
compete
at well
where
cell cogenerators become
consumers
sites
modelling
shows
American
significant
savings
the local
electricity
European
markets
provides
Global
to
a result,
better
supply
of
electric
pipeline
and
an d Othc :r the
fu, :I
to build two,
a filter to remov
air and fuel low-temperature
enter
‘e
th ,e heal
in stages t 0
through
and is therefore
introducing
fuel Global
natural cell
alliances its stationary
Four
the system.
15.cell
stack
component
to heat
the
entire
in the afterburner
A parallel
arrangement
legs in series
the desired the
electrical
natural
gas as fuel, the system
afterburner
(20.9
In total,
(LHV).
the system to operating The target
approximately
level
power
V at 65.0 A) using ratio
for more
cycled
temperature
electrical system
applications
on two
efficiency
for this
is above
45%.
are integrated,
efftciency
is
expected
the to
distribution
GOFC
to to
liquids
for
Canadian
the world
technology
automotive
is also being
applications.
s on the development
establish
fuel cell products.
be
80%.
to and
positioned
plans
at than
thermally
and operates
systems
of
in a system was obtained
was run
room
the
up to
The
of 720°C.
Tom
:ombined
was brought
This
h, and was successfully
gas-
7).
air, resulting
1150
occasions.
(Figure
gas at a steam/carbon slpm
of to
sulfur-containing
temperature.
was 1.35 kW
used
was used
output
and
achieved
SOFC
stacks were
Using
:he operating
a kW-class
15-cell
obtain
heating
and
gas
throughout
the
SOFCstacks for automotive applications
oil
well
system
June 2000,
system was tested.
When
heating
start-up,
1 kW demonstration In April
Enbridge for
the
gas/air mixture.
reforming-based
owns
also owns
company, residences.
and
largest
largest
distribute
are
is performed
only
the natural
using
and further
cold
is contained
iteam
natural
Enbridge
Canada’s
additional
to ignite
mixture,
energy
Global
suitable
power
in
2000
distribute
world’s
systems,
initially with
products
its
to establish the company
alliance
homes. the
define
and
in July
and
instances
prices.
partner
a strategic
individual
Preheating
the
stack temperature
marketing
cell
xchangers.
The through
thermal
which
and pre-reforms
On
of 30%
American
access for these products,
fuel
on
compounds.
is
supplying
is
and de-sulfuriser.
Jel cell system
air.
Efficiency
are in many
products,
fueled
realise
ulfur
incoming
system. An igniter
big! 1-
stack.
components
preheats
m average
prices
to develop
SOFC
gas/water
I20
for
announced
system
the
natural
natural
order
As
in
costs, depending
umidifier
and
preheats
incoming afterburner
integrated
the stack anode exhaust
exhaust,
1,
an
the
pre-reformer
Fuel may first be fed through
both
may
mportant
containing
heat-exchanger,
oxidises
The
component,
These incluc le
heat-exchanger,
module
in the afterburner
module).
2.2, and
residential-based
operates
low-temperature
emperature
applications,
elements.
is converted
7.5 slpm
than North
a
when consumers
for residential
systen
in the
does not use all of the available
favourable,
higher
Inc,
that
steam reforming-based
of three main
‘Y g; 1s
on natural
is a well
conversion
may be still more
electricity
Canada.
he
to operate
stationat
that
stream
6).
structures.
much
sought
The
initial
by Global
an output
is a multi-functional
the cathode
the
and easily manufactured
gas price
and
since
market
savings,
costs decline.
markets
in energy
use fuel
energy
as system
and heat are captured, North
In
will
to realise overall important
Preliminary many
,r propane.
fterburner,
Mass markets,
electricity
products
ntegrated
and pipelines.
will
ommercial
omprised
and
to
developing
which is suitable
for cathodic
company
is
over
electrochemical
completely
from
developed
of the integrated
module
recovered
monoxide-rich
fuel, the remainder (part
pre-reformer,
a nickel-alumina
Since the SOFC
hour
gas mixture
the
process low-cost
stack (Figure
is and
the endothermic
which
hydrogen/carbon
800
a steam/natural
pre-reformer
component,
250
Water
gas stream,
is used to drive
is an extremely
5 a”
differentials
components.
vaporises chemical
.g 2 0”
temperature
mechanical
auxiliary to
power
o develop vi11 provide
unit
a highly
developed
At this time, of gasoline-fueled (APU)
efficient
all the required
systems.
for
the focus SOFC The goal is
fuel cell system electrical
power
that on
Fuel Cells Bulletin No. 26
the
vehicle,
engine
while
will
propulsion. more
the
internal
continue This
practical
to
approach
the propulsion
source.
a
the
threat
to
combustion fuel
system
extremely
low
propulsion
systems.
The is based
on the
monoxide
(it
dramatically lower
sensitivity light
of
recovery
system,
control
developed
I
600
ct
20.0
a
200
,I
*
‘=*
1
0
0
10
20
40
30
Current,
50
60
70
I (A)
to
tests
the Global well.
The
compression gas
(42 V) and of
operating stack
Electrical
that
cells
and
waste
load
low-cost 25
power SOFC designs
have significant advantages applications, is already beginning
automotive
kW)
SOFC
into
SOFC
1. D. Ghosh,
for
(1 kW to in
mass
markets
manufacturing
demonstrated
unique
interconnect of
using
manufacturing membranes
will
casting
residential
systems
is are
steel
high-volume
processes. Likewise, be manufactured
the fuel cell using tape-
technology,
Field-testing in
SOFC
and
commercial
introduction
to niche
applications)
is expected
Later in cogeneration quantities become
2003,
markets the
Canadian
May
2000
The
822-829.
D.
Prediger,
and D. SOFC
applications. Hydrogen
VI
1999,
M.
Ghosh: systems
Proceedings
Conference,
of
Quebec,
(in press).
3. C. DeMinco,
S. Mukerjee,
J. Grieve,
M. Perry, A. Horvath,
Pastula, R. Boersma
and D. Ghosh:
of a solid oxide fuel cell (SOFC) auxiliary power unit (APU) fueled Proceedings
of
Conference,
Quebec,
10th May
Canadian 2000
M. Faville,
D. Prediger,
M.
Development auromotive by gasoline. Hydrogen
(in press).
systems
will
product
(remote
power
For more information, contact: Eric N. Potter, Global Thermoelectric Inc, Bay 9,370O - 78th Avenue SE, Calgary,AlbertaTZC 2L8, Canada.Tel: +l 403 236 5556, Fax: +1 403 236 5575, Email:
[email protected]
by the end of 2002. first
residential
products, again in small for niche markets, are expected to
available.
Based on recent advances a general
PV 99-19,
planar
SOFC
a high-
used in the computer
of small 2001,
power
10th
J. Noetzel,
which stainless
Pastula,
for remote
power
chip industry. b egin
November
Perry, A. Horvath, J. Devitt Development of low temperature
Thermoelectric’s
low-cost,
process
Hawaii,
of
R. Boersma,
components,
and screen-printing
Conference,
E. Tang and E supported
Proceedings Society,
of
available
cells.
2. M.
of SOFC
commonly
materials
SOFC
R.Brule,
of anode
Electrochemical
designs,
auxiliary
in Global
G. Wang,
Performance
stack
systems can leverage their operation on hydrocarbon
and automotive
Huang:
temperatures,
applications.
made the
SOFC
Improvements
improved
the
cogeneration unit
of small-scale
at low operating
with
suggest that SOFC advantage of simple fuels
in
up the potential
systems.
density
combined
being
determined
opened
volume/low-cost
shift
in perception
SOFCs have limited balanced perspective
Fuel Cells Bulletin No. 26
for certain to occur in the
References advancements
have
Low-cost
thermal
withstood
consistent
such
fuel cell and related sectors.
manufacturing
power
successfully
testing
stacks
changes
of
significant
system,
typical
and
load
Conclusions Recent technology
proprietary
systems
demands
the
system,
with
and cell
and rapid
wtth
main
four
company’s
demanding applications.
on gasoline
separation,
cyclability.
in
for automotive
requirements,
reformate,
the
I
or
have been sized to meet
consisting
performed achieved
I
1 1400
.
An
pack.J31
voltage
kW)
air
electronics
stacks
In recent
and
I
-
and
fuel reformer
process
battery
configurations
seal
following
polymer
automotive
stacks.
I
.
.
*
fuel
SOFC-based
system,
and power
by Global
(3-5
the
Conference
system,
energy
output
I
24.0 22.0
Automotive’s
the
stack
management
future
9
1-l.
such as sulfur
Delphi
thermal
SOFC
*
thus
in conventional
system,
The
of
Hydrogen
consist
applications
fuel,
systems),
automotive
SOFC
and a lithium
APU
and is not linked
in
a typical
subsystems:
SOFC
I
drivetrain.
at the Canadian will
I
which
in the reformate.
explained
APU
cost
to contaminants
electric
I
26.0
of carbon a
PEM
can be applied
2000,
for
the with
configurations,
paper
needed
as
mild-hybrid
May
the
levels
CO
hydrocarbons
As was
the
on gasoline,
SOFC-APL-J a fully
that
to reach
tolerance
reducing compared
I
is not
of the SOFC-based
uses
1
internal
need
operation SOFC’s
34.0
a fuel cell as
approach
also ensures
not
cost/kW
is its simple
processor
using
established
and
key advantage
system
and
well does
for as a
- implementation
than
The APU
engine,
cell
power
is considered
- and simpler
of a fuel cell in a vehicle
combustion
provide
in SOFC from
technology, the view
that
commercial value, to a more recognising that SOFCs
0