United States Department of Energy Office of Fossil Energy Project Fact Sheet
MATERIAL AND PROCESS DEVELOPMENT LEADING TO ECONOMICAL HIGH-PERFORMANCE THIN-FILM SOLID OXIDE FUEL CELLS
A three-year program is proposed to develop an advanced high-performance solid oxide fuel cell (SOFC) for the 21st century. The overall objective of the proposed work is to demonstrate a SOFC cell that is capable of achieving extraordinarily high power densi-ties at reduced temperatures (with the goal of 1 W/cm2 at 600EC) and can be produced by cost-effective fabrication processes. The proposed work is focused on developing high-performance electrolyte and cathode structures and integrating these structures as thin layers in an anode-supported cell for reduced-temperature operation. High electro-lyte performance will be achieved by using high-conductivity electrolyte materials based on lanthanum gallate. High cathode performance will be achieved using several approaches, including new materials and engineered structures, to significantly improve cathode properties. SOFCs based on these electrolyte and cathode structures have the potential of achieving high power densities at low temperatures while possessing desired operating characteristics. Successful demonstration of this SOFC can be used as a tech-nology base for the development of 21st century fuel cells, leading to improved fuel cell economics.
dominoweb.fe.doe.gov!OpenDocument ... more project details
The excerpt below is from a world leading manufacturer of mass produced 'ceramic' fuel cells ...
FUEL CELLS: RAPID GROWTH IN 2001
In the past year, Global's fuel cell work has received widespread recognition. Our development is extensive
and is proceeding at a rapid pace, evident in the growth of the Fuel Cell Division. By year-end we had a team
of over 30 highly qualified employees in the group.
That number is expected to grow substantially as we get ready to launch our first commercial fuel cell products.
The Fuel Cell Division relocated its offices in August 2000 and plans to have an operational pilot SOFC
production plant - Canada's first - in 2001.
The company has successfully enhanced the base fuel cell technology. Client testing has confirmed : that both
the cells and stacks function well. The company's mission is to become the recognized planar SOFC technology
leader, and to become the world's leading supplier of scalable SOFC products. This progress will be realized
through ongoing technological breakthroughs, the implementation of the pilot production plant and the
development of strategic alliances.
IMPROVEMENTS IN BASE TECHNOLOGY
The company continues to realize very significant improvements in basic fuel cell design. A measure of our
success is the improvement in single cell power densities (see table). Since initial development work began in
1998, Global has realized a 486% improvement in power densities at 800°C. As important, at 700°C, the
Global fuel cell yields 0.723 watts/cm2.. We believe Global's cells have the highest published power densities
for commercial-sized SOFC membranes in the world. Changes in cell composition and design have resulted in
these improved power densities. Higher power densities contribute to lower weight, size and cost of fuel cell
systems.
Evolution of Single Cell Performance measured in watts/cm2 @ 0.7 V using hydrogen as fuel
Global 4 ... 1.216 watts/cm2 @ 800°C
HOW A FUEL CELL WORKS
A fuel cell is an electrochemical device which combines hydrogen fuel with oxygen to produce electric power
heat and water. The fuel is not burned, but is electrochemically combined with the oxygen in air limiting
harmful nitrous and sulfur oxide emissions. As there is no mechanical process, a fuel cell is very efficient.
A solid oxide fuel cell (SOFC) consists of three main solid parts: the anode, a cathode and an electrolyte. The
anode and cathode are porous and allow only certain gases to pass through them. Between the two is an
electrolyte (which conducts electricity) that will only allow oxygen ions to pass through from the cathode to the
anode. The oxygen ion combines with hydrogen to form water, heat and electricity. As the oxygen ion passes
through the electrolyte' the resulting excess of electrons on the anode side completes an electrical circuit
through an external load to the electron deficient cathode side for the production of a flow of electrons or
electricity.
The SOFC is a desirable fuel cell for generating electricity from hydrocarbon fuels. This is because SOFCs
operate at elevated temperatures and are tolerant of fuel impurities including carbon monoxide. The fuel
reforming process, which involves breaking the hydrogen-carbon bond, yields both carbon monoxide and
hydrogen. Carbon monoxide is a supplemental fuel in a SOFC as oxygen ions pass through the electrolyte
from the cathode to the anode and combine with carbon monoxide to form carbon dioxide to generate
electricity.
FUEL CELL STACK DESIGN AND SYSTEM COMPONENTS
Global's stack development features a 10x10 cm planar cell design. Cells will be manufactured using
tape-casting production technology, an established production process in the computer chip industry. The
interconnect plates which hold the cells in place are made of standard stainless steel components and have
been designed to be made by low-cost high-volume stamping processes. The assemblies are lightweight,
durable and thin, allowing for higher power densities, long life and low stack volume. One of the unique
features of Global's stack design is a proprietary high temperature compression seal. This allows for fast
heat-ups and cool-downs, and reduces thermal stresses between the individual cells and interconnects. Stacks
are generally arranged in a modular manner to provide flexibility to the system layout and to allow for
condition monitoring of each module and, if required, the freedom to replace individual modules rather than
having to disassemble a complete system.
Global's initial stationary commercial products will use natural gas or propane as fuel. Global's system is
comprised of three main elements (Figure 1 shows the high level system architecture). These include the low
temperature heat exchanger, an integrated module containing the high temperature heat exchanger,
pre-reformer and afterburner, and the SOFC stack.
Other important system components are the fuel humidifier and de-sulphurizer. Fuel may first be fed through
a filter to remove sulphur compounds. The air and fuel enter the fuel cell system through low temperature heat
exchangers. Preheating is done in stages to ensure acceptable temperature differentials within mechanical
components. Water is then added to the warm natural gas stream and vaporizes to provide a steam/natural
gas mixture for the pre-reformer. In the pre-reformer, chemical and thermal energy recovered from the stack
output is used to drive the reforming process over a nickel-alumina catalyst. The pre reformer developed by
Global is an extremely low-cost and easily manufactured appliance. The pre-reformer output is a
hydrogen/carbon monoxide rich stream well suited for electrochemical conversion in the stack. It should be
noted, that the SOFC uses carbon monoxide as supplemental fuel whereas in a PEM fuel cell system,
additional steps must be taken to remove the carbon monoxide, a poison to the platinum catalyst.
Whether in stationary or automotive applications, Global's fuel cell systems will be highly integrated and
modular and will use the same basic cell and stack designs. Our systems will have enhanced operational
efficiencies as stack exhausts are recycled. The fuel cell stack interconnects are made of commonly available
materials using low-cost hi, in-volume manufacturing processes.
FUEL CELL STACKS FOR AUTOMOTIVE APPLICATIONS
Delphi Automotive Systems, the world's largest manufacturer of automotive parts and systems, is utilizing our
fuel cell stacks in the development of an automotive gasoline-fueled Auxiliary Power Unit (APU). In April and
August of 1999, the company received purchase orders from Delphi for a total value of approximately $1.3
million.
The stacks developed for automotive applications have been sized to meet future automotive voltage
requirements (42 volts) and power out-puts (3-5 kW). The stack configuration consists of four modules. The stacks are integrated with a Delphi's APU system which includes the fuel reformer and other components.
In tests completed by both Global and Delphi, the Global stack and cell designs performed well. The cells
operated on gasoline fuel reformate and the proprietary seal and compression systems successfully achieved
gas separation and thermal cyclability. Electrical load testing determined that the Global cells and stacks
withstand demanding and rapid load changes.
SOFC technology used to support an APU is a workable solution to address demands for more electrical
capacity in automobiles characterized by the development of new 42 volt systems (existing systems are only
12 volts). An APU will rid internal combustion engines ICE) of power draining parasitic loads' and improve the
ratio of lCE power, which contributes directly to propulsion.
SOFC STATIONARY APPLICATIONS - AN OVERVIEW
Distributed power generation opportunities for Global's SOFC products are very significant Markets such as
residential cogeneration could be as large as and may come to fruition earlier than transportation markets.
Global's SOFCs are expected to have cost and efficiency advantages over other products and are well suited
where both the electrical and heat output of the fuel fell system is desired.
Distributed generation is on-site generation of electricity that supplements or bypasses the pubic power grid.
Distributed generation in the form of back-up power has been around for years predominantly in the form of
diesel generators, photovoltaics (solar power) and more recently micro-turbines. Global's own thermoelectric
generators are a form of distributed power generation intended for use in remote locations. In the coming
decade, distributed generation is expected to become widely used, not only as back up power, but a so for the
primary generation of power on-site. These changes are caused by the deregulation of public utilities coinciding
with a tight supply of traditional generation capability and new demands for more reliable or "high grade"
power capable of supporting a digitized world ' These market pressures are a long-term global trend caused by
economic and population growth and an increasing reliance, particularly ill service-based economies, on digital
tools which require reliable electricity. Deregulation is a contributing factor by bringing market-based pricing
mechanisms to the power industry and reducing barriers to entry. Deregulation is also creating an environment
which a convergence of energy industries can occur, Thus, for example, natural gas suppliers may enter the
marketplace offering distributed generation produce which use natural gas as fuel. Underlying these changes is
a strong level of public concern about global warming, and support for alternative "green energy" technologies.
These factors have combined to engender an environment that welcomes innovation. Fuel cell systems have
the potential to provide distributed power generation solutions on a very wide basis. Such products will not only
produce electricity with greater efficiency in a more environmentally-friendly way, but are also scalable
(meaning that, within a wide range, efficiency is relatively constant), and will work well on a small scale where
other solutions do not have this flexibility.
In home and small-scale industrial applications where both electrical and heat outputs can be used (called
cogeneration), SOFCs are very well suited. Global's SOFCs are expected to reach efficiencies (the rate at which
fuel is converted into electrical power and heat) of up to 85%. Even in the absence of cogeneration, SOFCs
have a high base efficiency and in Global's case, systems are expected to be less costly to produce due to
savings associated with the absence of complicated and expensive fuel reformers.
GLOBAL'S STATIONARY COMMERCIAL APPLICATIONS
Global's initial focus is on the development of 1 kW to 25kW systems using natural gas as fuel. The company
has made significant progress towards developing commercial products in this area. We have operated two
natural gas fueled prototype systems. The most recent system test, completed in June 2000, provided 1.35
kW of peak power and operated in excess of 1,100 hours. The output of this system is sufficient to meet the
base load residential power requirements in many markets.
In 2001, Global's pilot fuel cell production plant will be operational and ready to produce prototypes for off-grid
remote power and home cogeneration applications. Initially, units will be tested extensively with our Canadian
ally, Enbridge Inc. and with oil and gas producers and telecommunication companies in Canada and in the U.S.
Subsequently, a second round of field tests involving a larger quantity of units will occur in 2002. This second
round may include testing of applications connected to the power grid and involve may testing in countries
outside of North America.
Remote power markets, where grid power is unreliable or where obtaining grid power is costly, will likely be the
first users of our fuel cell systems. These are markets with which Global is thoroughly familiar on a worldwide
basis and represent an area where our Company is likely to quickly establish a significant presence. Global's
fuel cell products will complement the Company's thermoelectric generator products, used primarily for cathodic
protection and remote instrumentation, and should allow the Company to compete successfully for
multi-kilowatt projects at well sites and pipelines.
Mass markets, where consumers will use fuel cell cogenerators to realize overall energy savings will become
important as system costs decline. Our preliminary modeling shows that when both electricity and heat is
captured, consumers in many North American markets may realize significant savings in energy costs
depending on the local electricity and gas price structures. European markets may be still more favourable as
electricity prices are in many instances, much higher than North American prices.
globalte.com .... Shifting the Balance of Power
It appears that bldp has taken the wrong path ... LOL |
