An experimental all solid-state fuel cell - the possible prototype
for a future "combustion-less" power plant - has passed a key
milestone in a joint public-private development effort.
The Siemens Westinghouse
solid oxide fuel cell is a tubular arrangement of concentric ceramic
electrodes and a solid-state electrolyte.
Siemens-Westinghouse Power Corp., headquartered in Orlando, FL, announced
this week that its 100-kilowatt solid oxide fuel cell power system, the
world's largest, has completed one year of total operating time, the longest
any fuel cell of this type and size has run. The milestone marked the
halfway point in a 2-year demonstration program that is verifying the
durability and performance of this potentially revolutionary new source
Installed at a cogeneration plant in Westervoort, the Netherlands, the
unit is one of several being developed by Siemens Westinghouse under a
jointly-funded $196 million program ($114 million is the non-federal share)
with the U.S. Department of Energy's National Energy Technology Laboratory
(NETL), a field center for the agency's Office of Fossil Energy.
The unit was developed and manufactured at the Siemens Westinghouse Science
and Technology Center in Pittsburgh, PA.
A solid oxide fuel cell is an all-ceramic power generating device. It
uses no boiling liquids or moving parts to generate electricity. Like
a battery, it produces electric power by an electrochemical reaction,
avoiding the air pollutants and efficiency losses associated with traditional
combustion processes. Unlike a battery, it can operate continuously as
long as a fuel, such as natural gas, is supplied to it.
The test unit installed at the Dutch power station has operated for a
record 8,760 hours. It is supplying 110 kilowatts of electricity to the
local power grid - better than its "namplate" capacity - along
with hot water to the area's district heating system.
To date, the unit fuel-to-electricity efficiency has reached 46 percent
- significantly better than a conventional power plant which typically
converts only 33 to 35 percent of the energy value of fuel to electric
High efficiency is one of the main advantages of the solid oxide fuel
cell. Boosting a power plant's fuel use efficiency is one of the best
ways to reduce emissions of greenhouse gases. It is also key to economical
energy production. Future versions of the solid oxide fuel cell are likely
to be linked to a gas turbine in a "hybrid" system that could
achieve efficiencies as high as 70 percent. When waste heat from the process
is used, overall efficiencies could exceed 85 percent, and greenhouse
gases could be cut by almost two-thirds compared to a conventional coal-burning
The solid oxide fuel cell also offers other impressive environmental
benefits, which are being verified by the Netherlands test. Emissions
of nitrogen oxides - a pollutant that can form smog or acid rain - have
been held to 0.2 parts per million, well within the most stringent of
air quality standards. Sulfur oxides, carbon monoxide and volatile hydrocarbons
were all measured at less than 1 part per million.
The test unit was installed at a Dutch cogeneration plant in 1998 as
one of several units to be tested in the joint government-industry development
effort. The Netherlands test is being carried out by NUON, the local utility
in Westervoort, which operates the system for EDB/Elsam, a group of Dutch
and Danish utilities. Funding for the test is also being provided by the
Dutch government agency Novem, in addition to the Energy Department and
"We are very pleased with the operation of the 100 kW system as
a whole and the prototype pre-commercial cells in particular," said
Siemens Westinghouse Vice President and Chief Technology Officer Nick
Bartol. "This gives us and our potential customers great confidence
for the commercialization of solid oxide fuel cells as a distributed generation
The company plans to make its first solid oxide commercial deliveries
in the 250-kilowatt to 1000 kilowatt range in 2004.
Dr. Mark Williams, the Energy Department's fuel cell product line manager
at NETL, agrees that the future is promising for fuel cells as an ultra-clean
power technology that can be sited at modular scales near the power consumer.
The major hurdle is to reduce the initial costs of the fuel cell units.
"The potential value of fuel cells is already widely recognized,"
Williams said. "What the technology needs are costs that are competitive
with other types of power production."
Williams said that one of the keys to reducing costs will be to complete
the development of a high-volume manufacturing process required for lower
cost commercial production. Another way to reduce costs is to develop
a solid oxide fuel cell module that operates at elevated pressures. A
pressurized unit would emit a higher-energy exhaust that would be more
suitable for driving a gas turbine-generator to produce two sources of
electricity and increase overall efficiencies. Another key is to develop
lower cost "balance of plant" equipment.
The Dutch demonstration is to be followed by additional tests at different
scales and in varying market applications. A 250-kilowatt fuel cell/gas
turbine hybrid power system in California is to begin in March. Ontario
Hydro is to be the next North American host for a 250-kilowatt solid oxide
fuel cell demonstration later this year. All of the demonstrations, including
the system in Holland, use natural gas.
NETL conducts DOE's fuel
cell research and development program. The program targets the stationary
power-generation sector, and includes extensive participation by private
industry. DOE's goals are to enable industry to take advantage of fuel
cells by reducing costs and enhancing performance, and to strengthen the
nation's economy by developing American leadership in manufacturing fuel