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The 2005 Fuel Cell Seminar held at the Convention
Center in Palm Springs, California, November 14-18
was well attended by more than 2,400 participants
and 117 exhibiting companies. The conference continues
to be an excellent event for those engaged in
all aspects of the fuel cell industry since it
brings together those involved in the full spectrum
of types, sizes, and applications for fuel cells
and representing the cross section of participating
organizations from commercial companies, to government
agencies, and academic institutions. Plus, the
conference offers a variety of ways to access
technology and business information ranging from
a vendor exhibition area, a program of technical
presentations, poster sessions, a series of educational
courses and, of course, the opportunity to network
and meet directly with the people involved in
the technology at various receptions.
Technical Program Overview
The program for the technical presentations
was divided into three tracks: High-Temperature
Fuel Cells, Low-Temperature Fuel Cells, and Applications.
The High Temperature was devoted almost exclusively
to solid oxide fuel cells (SOFC) with the poster
sessions providing some presentations on molten
carbonate (MCFC) which is best suited for primary
stationary power for 100kW to multi MW, and phosphoric
acid (PAFC) posters. The Low Temperature section
covered polymer electrolyte membrane fuel cells
(PEM FC) and direct methanol fuel cells (DMFC).
The Applications session covered on-going development
programs and experience with fuel cells for power
plants, residential electricity and heat, mobile
fuel cells for transportation, distributed generation
for and backup power for telecom, and critical
services like hospitals and financial data centers,
and portable power for electronic devices, like
laptop computers. While each application had its
own driving benefit, whether improved air quality
in transportation or energy density in portable
applications, they all had the common thread of
cost as a major obstacle. The strongest inducement
for acceptance of fuel cells into each of the
applications will be reaching a price that is
compelling against the existing power solutions
being used today.
Plenary Session – Fuel Cells
and Transportation
The opening plenary session featured an award
to Dr. Alan Lloyd of the California Environmental
Protection Agency, who was recognized for his
work on zero emission vehicle legislation and
chairing the California Fuel Cell Partnership.
Byron McCormick, executive director of fuel cell
activities for General Motors, provided a view
of the company’s fuel cell program. Noting
all the recent interest and publicity in hybrids,
McCormick made it clear that GM still sees fuel
cells as the real end game for a number of fundamental
reasons. GM’s strength is selling style and
utility. Fuel cells with a single power source
and electric drivetrain allow that. Existing technologies
with their multiple engine and transmission combinations
require an emphasis on array of technical components
and require a lot of compromises in packaging.
The GM skateboard concept is an example of the
freedom that designers will have in a fuel cell
platform. Most importantly hybrids, while highly
fuel-efficient, still do not resolve the oil dependence
and emissions issues which can only be fully satisfied
in a hydrogen-based transportation system.
Addressing the same topic of fuel cells in transportation
was Russ Bosch, chief engineer at Delphi for solid
oxide fuel cells (SOFC). He provided some perspective
on the present state of the car industry’s
struggle to change its reliance on the internal
combustion engine (ICE) by looking at the last
major change in power in transportation –
from animals to engines at the turn of the previous
century. There was no fuel infrastructure at that
time and there were many competing power technologies
in steam and electric. In this environment, it
took 20 years to sort out all the issues before
manufacturers were whittled down to a small number
with clear technology winners. Delphi is looking
at SOFC as one of a number of technologies. One
of the strongest points being – it can work
with a number of current fuels that do not have
the same generation, distribution, and storage
issues as hydrogen. Plus, the lower number of
parts helps reduce cost and contribute to reliability.
The other challenge facing the fuel cell business
is more financial than technical. At this point
the business is primarily R&D and a large
amount of capital is needed. Venture capital and
traditional business borrowing and investment
are not sufficient. The government has a role
to play in stimulating the early adopter market
and providing development incentives.
Plenary Session – Fuel Cell
Investing
As a mark of the importance of the economic
aspect of the transition to a fuel cell world,
one of the plenary sessions was devoted to the
financial and business side of the fuel cell industry
dealing with topics on investment. The messages
that came out of the talks here are that the government
has a pivotal role to play in the transition because
market forces for reducing emissions and oil imports
are not sufficient to overturn the existing infrastructure
in a short time frame. Companies should not be
under any illusions and must realize their fuel
cell products will be purchased primarily on cost.
The business structure and model of fuel cell
companies needs to incorporate a long R&D
phase and an early adopter marketing approach.
Information from Papers and the
Exhibition Floor
Simulation tools for fuel cells. Finite element
analysis (FEA), computational fluid dynamics (CFD)
and various mathematical techniques based on partial
differential equations are being used to model
various physical phenomena in fuel cells –
distribution of fuel and oxygen to the stack,
thermal gradients, thermal distribution for design
of heat transfer and cooling, thermally induced
stresses, water condensation and flooding that
prevent proper gas transport, and current and
voltage distribution. Gary McVay of Pacific Northwest
National Lab (PNNL), says solid oxide fuel cell
development works on developing modeling tools.
Modeling can “build, test, break, and fix”
virtual fuel cells and provide insight into what
is often a very complex relationship among a number
of nonlinear parameters like flow, temperature,
geometry, and mechanical components. The University
of South Carolina’s Engineering College and
Information Technology’s Department of Chemical
Engineering have developed subroutines for modeling
physical phenomena in fuel cells.
Proton exchange membrane development. Fluorocarbon
PEMs now have competition from hydrocarbon and
composite variations of PEMs for DMFC and automotive
PEM FCs. While there are gains and improvements
in some metrics, targets for durability and cost
in automotive where their success is absolutely
critical remain a distant 3-5 times away for all
approaches so far. The following is an overview
of some of the main participants in PEM technology:
DuPont. The long-time producer of the Nafion PEM
and Gen IV MEAs for DMFCs and hydrogen based PEM
FCs reports a 20% increase in power density with
less catalyst loading, and a two-time increase
in durability. Fluoride ion release and membrane
thinning are common measures of membrane chemical
attack and are used for durability indicators.
W.L. Gore. Dry reactant, high temperature operation,
low catalyst loading, duty cycle power transients,
start up/shut down, and freeze tolerance are the
edges of the performance envelope that PEMs must
satisfy. Durability failure for fluorocarbon PEMs
can be broken down into two categories: mechanical
and chemical degradation of the ionomer. Ionomer
membranes swell in x y z direction in response
to RH changes, and with the membrane constrained
stresses result. Adding reinforcing materials
are one strategy being tried and new membranes
show a five-time improvement in certain life tests.
Temperature, pressure and low RH contribute to
ionomer chemical gradation. Materials tested in
these aggressive conditions allow promising candidates
to be identified. Some accelerated testing schemes
have been developed like carbon corrosion testing
conducted by holding the cathode at 1.4V versus
RHE and measuring the CO2
evolved in the electrochemical active area. Similarly
Pt dissolution and sintering accelerated tests
help identify mechanisms and guide material development.
3M. Durability is affected by surface area loss
of the Pt catalyst which can be from support corrosion,
Pt dissolution, oxidation, or agglomeration due
to high voltage excursions of the electrode during
start-stop cycling or momentary fuel blockage
by water which can be critical in Pt oxide film
formation. 3M has shown promising results with
nano-structured thin film (NSTF) catalyst electrodes
which are much more resistant than conventional
Pt on carbon
Hydrocarbon PEM at PolyFuel. Jim Balcom, CEO,
has tuned up the development and prototype delivery
machine at PolyFuel. Investing in fabrication
and test hardware and putting in place a formulate-test-modify
process that is designed to quickly feed back
lessons learned and squeeze every ounce of time
out of the R&D cycle, he has sampled all the
major players involved in portable FCs with names
like Sony, Sanyo, Toshiba, Samsung, LG. Among
the benefits of PolyFuel’s hydrocarbon PEMs
versus fluorocarbon type membranes are: lower
cost, less catalyst, longer runtimes, and less
water recovery. In automotive, hydrocarbon membranes
are working towards performance parity in durability
with fluorocarbon PEMs while offering the enticement
of an extreme cost advantage of $1300/car in the
10K cars/year production and a $200/car benefit
at a 35K annual vehicle production number.
PEM with aromatic structure and sulfone ion exchange
substrate. Honda claims its own proprietary PEM
in its FCX fuel cell vehicle has a chemical structure
consisting of a main chain with an aromatic structure
and a sulfone ion exchange substrate. The aromatic
structure provides high thermal stability and
durability. Contrast this with fluorinated electrolyte
membranes which become soft and deform at high
temperatures. The sulfone has very high ionic
conductivity which is what supposedly allows their
low temperature operation (-20°C).
Kynar polyelectrolyte PEM composite. Arkema, Johanson
Matthey, and Nissan have teamed up on a PEM composite
consisting of Kynar PVDF (polyvinylidene fluoride)
for mechanical strength and chemical resistance
blended with a polyelectrolyte to provide the
necessary proton conductivity to allow a more
tailored approach. They are demonstrating superiority
in some specific properties, e.g., gas barrier
properties and dry tear, but still need to find
the right recipe for success in others.
Single wall nano tube (SWNTs). Also known as Buckytubes,
SWNTs for PEMFC and DMFC are being explored by
Carbon Nanotechnologies, Motorola, and Johnson
Matthey Fuel Cells. Benefits of the material are
high surface area, electrical conductivity, mechanical
strength, and potential for proton conductivity
which allow tough, thin porous mats with high
thermal conductivity. The expectation is that
corrosion of the catalyst support in conventional
PEM FCs can be overcome because the SWNTs do not
have the edge planes of graphitic sheets.
Nano-porous proton-conducting membrane. Green
Fuel Cell of Israel claims a nano-porous proton-conducting
membrane with a cost today of $40/m2
that delivers 200mW in a DMFC and is a solution
to water management. High temperature polymer
polybenzimidazole (PBI) is being supplied by PEMEAS
of Germany (formerly Celanese Ventures GmbH) as
a PEM for Plug Power’s high temperature (160°C)
PEM FC.
Fuel Cells for Automotive
The fuel cell vehicles on display and available
for test drive at the conference seemed showroom
ready. You would not have the first idea from
the ride, appearance, and performance that buying
one may be 15 to 20 years off into the future.
While the fleet of vehicles fielded by the auto
companies represents a major milestone (there
are about 600-800 under trial across the globe)
a number of challenging obstacles remain: on board
fuel storage must be doubled to achieve an acceptable
driving range, power plant lifetime improvement
must increase five times, fuel cell drive train
cost must be cut to 10% of current costs, and
a clean hydrogen generating and distribution infrastructure
must replace the existing well established global
network of gas stations. The benefits to the country
and world of significantly improved air quality
and reduced dependence on dwindling oil reserves
(60% of annual oil consumption in the U.S. goes
to automobiles) are the compelling reasons that
keep development resources flowing.
FCV vs HEVs vs ICEs. H2Gen Innovations prepared
a green house gas emissions (GHG) and gasoline
consumption computer simulation for 100 years
comparing business as usual, with gas-powered
hybrid electric vehicles (HEVs), hydrogen FC,
(H2 FCVs) and hydrogen internal combustion engines
(H22 ICE). According to the simulation, the only
long-term solution to the dual problem of reduced
GHGs and imported oil is hydrogen-powered vehicles.
Where would the H2 come from? Transitioning from
a gasoline economy could come via reforming ethanol
at local filling stations which would provide
hydrogen at about $2.02 per gallon of gasoline
equivalent (untaxed) compared to $1.62 gas cost
today (untaxed). See Figure
3 showing hydrogen from corn ethanol at the
same cost as gasoline with half the GHG, and cellulosic
ethanol at less than today’s gas cost with
an 80% reduction of GHGs. Eventually the transition
would be complete going to H2 from renewable energy.
But what renewable energy source makes sense?
The projection shows electrolyzing water with
renewable energy (photovoltaic, wind) is actually
not a good choice for displacing coal-based grid
electricity. Ethanol is more effective in reducing
GHGs than making H2 for cars.
A Comparison of On-board Hydrogen Storage Methods
for Vehicles. A comparison of the volume, weight
and well-to-wheel efficiency of three proposed
systems of on-board fuel storage – compressed
H2, Metal Hydrides, and DME reforming – was
offered by a group led by Mitsubishi Heavy Industries.
A well-conceived graphical presentation helps
to capsulize the issues. Assume effective H2 storage
of 5.8kg is the same for all.
Honda FCX. Formerly Honda used Ballard’s
fuel cell stack in its 2003 and 2004 fuel cell
vehicles. The FCX 2005 has Honda’s own fuel
cell stack rated at 78kW or 104hp. It uses a proprietary
PEM with good low temperature conductivity, allowing
startup at -20°C. Graphite bipolar plates
are replaced with stainless steel that has electrically
conductive inclusions dispersed to improve thermal
and electrical conductivity and a passive treatment
applied to the surface to provide corrosion resistance.
Two carbon fiber tanks hold 3.75kg of H2
at 5,000psig providing a range of ~170 miles.
10,000 psig tanks would increase energy storage
by about 66%. 1kg H2=
39kWh. Fueling time is three minutes, about the
same as a gas car. An ultra capacitor bank is
used to deliver power at high rates and absorb
regenerative braking power at high rates. The
ultracaps don’t have the slower electrochemical
reaction of a battery or the attendant heat generation.
The capacitor has the simpler physics of just
storing electrons. Most other fuel cell cars use
batteries. Top speed is 93mph.
DaimlerChrysler. The fleet of fuel cell vehicles
for Daimler consists of 100 buses, vans, and cars
that are located throughout the world in all kinds
of driving conditions and weather. The F cell
uses compressed hydrogen at 350bar with an amount
sufficient for about 100 miles. Top speed is 85mph.
Sounds slow for the Autobahn, could be way too
fast for L.A.
Auxiliary Power Units (APU) for Trucks, Buses,
and RVs. A number of companies with deep experience
in present technology APUs are teaming with various
fuel cell companies to explore solid oxide fuel
cells (SOFC) for this application. Reduced emissions,
quiet operation and lower fuel consumption are
the benefits they are looking to provide.
SOFC on Reformed Diesel for Heater APU by Webastco
AG. A manufacturer of APUs for trucks and buses
is developing a SOFC heater that runs on reformed
diesel fuel. The 700W unit has 50 start/stop cycles,
2000 hours operating at 250ma/cm2
with 57% fuel utilization. Staxera GmbH is providing
the stack of planar cells. Reformer is being done
by Webastco and existing pumps and blowers are
used for balance of plant (BOP).
Vibration resistance of 16g in z axis and short
startup times of <1 hour are among the key
specifications that need to be met.
Ballard Road Map. Figure
6 offers a good way to visualize the current
state of Ballard’s fuel cell stack technology
for automotive, providing a perspective on what
has been accomplished and what is needed to reach
the milestones to allow a production decision.
LP Natural Gas SOFC APU by Cummins. Cummins Power
Generation is the world’s largest manufacturer
of generators for the RV market. The Department
of Energy’s Solid State Energy Conversion
Alliance (SECA) is developing 3-10kWe SOFC in
a 10-year 3-phase effort. SOFCo-EFS Holdings is
developing the all-ceramic planar stack and waterless
CPOX LP natural gas reformer. BOP design approach
is to use automotive components for cost and reliability.
Trials show power densities of 280 mW/cm2,
65% fuel utilization and power degradation rates
as low as 2%/500 hours of operation.
Delphi SOFC APU for Transportation and Stationary.
The focus is on 3-5kW SOFC development. A cell
cassette design using high-volume manufacturing
processes of stamping, brazing, and laser welding
has been developed with 30-cell stacks demonstrating
578mW/cm2, 24%
fuel utilization using simulated reformate ( 48.5%
H2, 3%H2O,
rest N2). Power degradation
has been ~10%/2000 hours.
Fuel Cell Electricity and Heat
for
Residential and Commercial Use
Distributed generation (DG) is being explored
because SOFCs are an energy source with virtually
no emissions versus the NOx,
SOx, CO and hydrocarbons
of conventional combustion generated heat and
electricity. They offer a big advantage in their
flexibility of using the fuels of today –
coal gas, natural gas, propane, biogas –
while being easily converted to hydrogen in the
future. DOE’s SECA is promoting SOFCs and
trying to cross the chasm from a niche solution
to the widespread first choice of the marketplace
by getting capital costs down to $400/kW for stationary
and axiliary power units (APU) by 2010, making
it the economic frontrunner. For comparison, a
diesel generator comes in at $800-1500/kW and
a natural gas turbine even less while SOFCs are
in the $3,000 to $4000/kW neighborhood. SOFC technical
feasibility has been demonstrated by successful
operation of 100kW combined heat and power plant
without any performance degradation over two years.
The heart of the system is a solid oxide electrolyte
which acts as a conductor of oxide ions at temperatures
of 600-1000°C. Ceramic material allows oxygen
to be reduced to oxide ions on the cathode. They
are transported to the anode zone where they react
with hydrogen giving up electrons to an external
circuit. The primary goal now is reduction of
capital costs. Under SECA, DoE has assembled six
competing industry teams – Cummins SOFCo,
Delphi-Battelle, General Electric, Siemens-Westinghouse,
Acumentrics, and Fuel Cell Energy. Different cell
designs and many collaborative efforts are under
way. SOFC can be configured as tube or plate.
The plate helps with manufacturing because a lot
of existing processes and equipment can be used.
Reforming can be done internally. The most common
oxides used are zirconia and yttria. One strategy
for cost reduction is mass customization of some
common modules.
General Electric is working on two SOFC systems.
An ambient pressure, simple cycle 5kW prototype
SOFC running on natural gas with auto thermal
reforming (ATR). Analysis indicates a 35% efficiency
target can be reached. A 40-cell stack with 16-inch
diameter planar cells yields 288 mW/cm2
and 80% fuel utilization, using simulated ATR
fuel. The second system is a pressurized hybrid
SOFC with a gas turbine using the residual fuel.
The SOFC produces 80% of the electricity. The
objective is to develop and assess multi MW system
concepts. Planar design SOFCs that are anode supported
with metallic interconnects run at 800°C with
a system efficiency >65%. The hybrid system
can operate on coal using a gasifier. The overall
efficiency of coal to AC power is at least 50%.
Several important demonstrations have been realized
– large planar SOFC of 40cm diameter, operating
pressures of 4atm, and 80% fuel utilization.
Siemens-Westinghouse. In an attempt to reduce
the ohmic resistance of conventional round tubular
SOFCs that have only two current routes with long
paths, an oval geometry tube design with integral
ribs that provide multiple electrical current
paths offering lower resistance through their
shorter distances has been developed. Other benefits
include reduced thickness of the air electrode
wall which lowers diffusion polarization losses,
and the geometry provides a volumetric power density
increase. Testing showed an increase of 50% in
power density going from a tube with 200ma/cm2
to a 5-channel design with 300ma/cm2
at 900°C, 85% fuel utilization. No performance
degradation was exhibited after 1000 hours. The
next step is optimizing the number of ribs.
Fuel Cell Technologies, Ltd. Since 2001, 5kW SOFCs
have been run using Siemens-Westinghouse’s
tubular cells in first generation field trials
in a variety of applications in a number of countries
for R&D purposes – small commercial combined
heat and power in Japan, volatile organic compound
elimination at Ford Dearborn, remote power in
Alaska, a residential CHP in Germany. There was
a build of 20 Generation2 units in 2005 that use
low pressure natural gas (2 psig). Cost reduction
is the next big challenge with $1,000-2000/kW
the immediate goal. A five-year payback can be
shown for SOFC over diesel generators in fuel
and maintenance costs at a price of $2,000/kW.
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