One of Professor Eric Wachsman’s solid-oxide fuel cells (SOFCs). Image: University of Maryland |
When most people hear the words “fuel cell,” they think of
eco-friendly, hydrogen-powered cars that emit nothing more than water.
And that, says Professor Eric Wachsman, director of the University of
Maryland Energy Research Center (UMERC), is one of the reasons we’re all not
driving one.
The U.S. Department of Energy’s (DOE) recent decisions about how to fund
fuel cell research, he says, are putting the country at risk of falling behind
in the development and implementation of the most efficient means of converting
fuel to electricity. Fuel cells have up to three times the efficiency of an
internal combustion engine.
“There is a problem in the perception of the public and policy makers,
and in the funding of our fuel cell programs, that hydrogen and fuel cells are
linked,” says Wachsman, a faculty member at the university’s A. James
Clark School of Engineering. “Hydrogen-based fuel cells are the technology
that has gotten all of the press and as a result we’re still waiting for a
future hydrogen infrastructure. Yes, fuel cells can run off hydrogen, but they
don’t have to.”
Another problem, Wachsman says, is America’s fixation on vehicles.
“It will take decades to create a nationwide hydrogen distribution and
storage system, and to convert every gas station into a hydrogen filling
station. That reality has turned fuel cells into a ‘future technology’ and has
resulted in a drastic reduction in the funding of fuel cell research by the DOE
in favor of developing electric cars, when in fact fuel cells can be used right
now in many stationary and mobile applications, including centralized power
distribution and power generation for homes, businesses, and industry.”
Most people are unaware that there are two kinds of fuel cells. The one in
the public eye, the proton exchange membrane (PEM) fuel cell, uses hydrogen to
generate power. The type of fuel cell Wachsman and his colleagues have worked
to perfect, the solid oxide fuel cell (SOFC), has a distinct advantage over its
PEM-based sibling.
“Solid oxide fuel cells are unique because they can oxidize any fuel,” Wachsman explains.
“They can run off of gasoline, diesel and natural gas today, and biofuels
and hydrogen in the future, whenever that infrastructure is in place.”
Hot technology
Still, nothing’s perfect, and Wachsman can sum up the reason why SOFCs aren’t
in large-scale production in a word: temperature.
“That is the issue,” he explains. “It’s the reason why the
automotive companies are using PEM fuel cells. PEM fuel cells operate at around
80 C (180 F), which allows them to startup fairly quickly. Current solid oxide
fuel cells currently operate at 800 C (1,500 F), so it takes a long time to
warm up to operating temperature, making them more applicable to stationary
power generation.”
Wachsman and his colleagues are working to change that. In an article in Science, the team outlines the technology behind a
new world record power density SOFC that generates two watts of power per square
centimeter at 650 C (1,200 F). The cell uses a bi-layer electrolyte developed
by Wachsman that is more than 100 times more conductive than the conventional
zirconia-based electrolyte operating at the same temperature—also a world
record. When the cells are assembled into a stack they should produce three
kilowatts of electricity per kilogram of material, more than an internal
combustion engine at approximately one-third the size.
The paper lays out a strategy to further lower temperature. The team
believes its improvements to SOFC electrolytes and nanostructured-electrode
designs could ultimately reduce the cells’ operating temperature to only 350 C
(660 F). At that temperature they could start up fast enough for automotive applications,
and would be more efficient and more affordable than current SOFCs because they
could be manufactured from less expensive materials.
Progress at risk
The DOE’s 2012 budget request, however, does not include funding for the SOFC
program, effectively eliminating it from the agency’s research priorities and
greatly reducing funding options for groups like Wachsman’s. This decision, he
believes, was made without a complete understanding of recent significant
advances in SOFC technology such as those described in the Science paper, which, combined with
their fuel-flexibility, put them in an ideal position to improve nationwide
energy efficiency today.
In Energy and Environmental Science,
Wachsman and his colleagues, Craig A. Marlowe and Kang Taek Lee, make the case
that SOFCs should be an integral part of our energy policy. SOFCs, they argue,
meet all of the DOE’s six key energy strategies: they deploy clean electricity,
make use of alternative fuels, help modernize the power grid, will help
gradually electrify the vehicles we drive, increase vehicle fuel efficiency,
and increase building and industrial efficiency.
“We don’t have to wait for hydrogen,” says Wachsman. “SOFCs
represent a solution for everything that you can think of in terms of producing
electricity and power today.”
