“Fuel cell technology could lead to the next industrial revolution,” speculates Ron Kander, a Virginia Tech professor of materials science and engineering (MSE) who is working with colleagues across several disciplines to make this technology a primary power source for the 21st century.
NASA has used fuel cells for decades in the U.S. space program, Kander notes, but more down-to-earth applications are emerging. To avoid the expense of running underground power lines, for example, the City of New York installed a fuel cell system to supply power for the Central Park Police Station. In Chicago, the transit authority is testing the use of fuel cells as a power supply in city buses. And the mining industry employs fuel-cell-powered vehicles in mines because the technology emits fewer pollutants than internal combustion engines.
At Virginia Tech, researchers associated with two centers are working to bring fuel cell technology into everyday use: the Energy Management Institute (EMI), directed by mechanical engineering (ME) professor Michael von Spakovsky; and the Virginia Tech Center for Automotive Fuel Cell Systems, a Graduate Automotive Technology Education (GATE) center established by a U.S. Department of Energy grant and directed by Doug Nelson of ME.
Neither von Spakovsky nor Nelson expected earlier in their careers to become leaders in fuel cell research. Before coming to Virginia Tech in 1996 to head up the newly established EMI, von Spakovsky spent eight years with the Swiss Federal Institute of Technology in Lausanne, studying and teaching direct and indirect energy conversion. “I became interested in fuel cells and saw their potential,” he says. In Blacksburg, he met Nelson and other faculty members with a similar burgeoning interest.
Nelson, with a background in heat transfer and automotive power technology, became adviser of the Virginia Tech Hybrid Electric Vehicle Team (HEVT) in the early 1990s. The team proved so successful in developing HEVs for the national FutureCar Challenge that the U.S. Department of Energy (DOE) gave the university a $250,000 fuel cell in 1998 for students and faculty to use in studying alternative automotive power systems. Later that year, Nelson received the GATE center grant.
Sir William Grove, an amateur scientist in Wales, built the first fuel cell in 1839. A fuel cell is a site for an electro-chemical reaction combining hydrogen and oxygen. The end result of the reaction is the release of water, electric energy, and heat. To produce enough power to be useful, fuel cells are combined in stacks. Depending on power density, a 20-kilowatt stack may contain more than 100 cells but be only about the size of a couple of breadboxes placed end-to-end.
“The fuel cell was invented before the internal combustion engine,” von Spakovsky says, “but engines quickly began to dominate because at the time they were easier and cheaper to produce, maintain, and operate.”
Why, then, a renewed interest among researchers and industries in a technology that was invented during the 19th century and then ignored until the 1960s, when NASA began using fuel cells to help power Gemini and Apollo spacecraft?
Unlike internal combustion engines, fuel cells emit significantly less carbon dioxide and other air pollutants during energy production. The DOE estimates that air pollutants could be reduced by one million tons per year and oil imports by 800,000 barrels per day if only 10 percent of domestic automobiles were powered by fuel cells. And unlike batteries, fuel cells don’t have to be recharged, although they do require a supply of hydrogen or hydrocarbon fuel.
In addition to producing low emissions, fuel cells have tremendous potential as high-efficiency power supplies. During the internal combustion process, for example, 20 to 30 percent of the power production potential of the fuel is lost. The electro-chemical process in a fuel cell avoids this loss by converting the potential in the fuel directly into electricity. “If we can combine fuel cells that operate at high temperatures with conventional power systems,” von Spakovsky says, “we can push energy production efficiencies up to as much as 80 percent, well above the limits currently reached by conventional systems.”
Despite these advantages, fuel cells are in short supply. They still must be custom made because no company has invested the capital needed to build mass production facilities, so cost is a major drawback to widespread commercial use. The technology also needs fine tuning.
“To improve fuel cells, we must develop new materials, as well as tools to analyze, predict, optimize, and integrate their design and operation,” von Spakovsky remarks. “That’s where the research is needed, and that’s what we’re working on at Virginia Tech.”
Automakers are already offering electric (battery-powered) vehicles on the commercial market, but they also plan to take advantage of the lower emissions and higher energy efficiency offered by fuel cells. “Battery-based electric vehicles have a short range and long recharge time,” says Nelson. “In the long run, we will see fuel-cell-powered cars.”
One type of research funded through the GATE center involves computer modeling of fuel cell systems to help achieve high efficiency for vehicle use. “Fuel cells can go from low power to high power in a short time if their air and fuel supplies, cooling systems, and air humidity are controlled correctly,” Nelson says.
GATE associates also are figuring out the best methods of providing fuel for vehicle fuel cell systems. “One of the major research issues for automotive fuel cell use is compressed gas hydrogen storage and conversion,” Nelson says. “Right now, it takes about 10 gallons worth of space in compressed gas hydrogen fuel to equal the energy in about one gallon of gasoline.”
Directed Technologies Inc. (DTI), a product development company based in Arlington, Virginia, is sponsoring a project through the GATE center to develop a better conversion and storage method. Frank Lomax, an ME graduate student and DTI employee, is developing an “off-board reformer” for fuel-cell-powered vehicles. An off-board reformer, located at a fueling station, could convert natural gas into hydrogen. The vehicles could fill up at a service station, just as gas-powered cars do now. Lomax is attempting to create an off-board reformer for a small fleet of vehicles. “Some researchers are developing on-board reformers, but they don’t work well,” says Nelson. “That’s like carrying a small gas refinery in your car.”
Researchers working on another DTI-funded project are designing low-cost collector plates for fuel cell stacks. Collector plates form the mechanical structure of the stacks and conduct electricity, Nelson explains. Fuel cells are composed of membranes that convert fuel to energy, separated by collector plates. “Right now, these plates are expensive,” Nelson notes. “When some company starts trying to mass produce fuel cell stacks, it will need an inexpensive method of producing collector plates.”
As part of the same project, Ron Kander is attempting to produce low-weight plastic collector plates. Currently, plates are made of metal, he says, but fuel cells made with plastic plates would be lightweight enough to be used to power portable devices, such as laptop computers.
The GATE center also funds five fellowships annually at Virginia Tech, and one has been used in the design and construction of a fuel cell test stand accessible to all faculty members and students involved in this research. Former ME master of science student Mark Davis, who received his degree in May, worked with ME assistant professor Mike Ellis and an undergraduate design team advised by von Spakovsky to develop the test stand. The stand, which was built from scratch with hardware funding from the university’s research seed money program (ASPIRES), can perform tests on fuel cell stacks up to five kilowatts in size. Soon the stand will be upgraded to work with higher temperatures, which will enable chemistry professor James McGrath’s group to test the effects of advances in materials on fuel cell performance. His group is developing polymers that are stable at higher temperatures.
Kander is working with another GATE fellow, Julie Dvorkin of MSE, to evaluate the performance of polymer materials in fuel cells. Proton-exchange membrane (PEM) fuel cells — the most suitable for automotive and other power-demanding uses because they operate at low temperatures — are polymer-based. The polymer membranes produce electric charges by separating hydrogen protons from electrons, or the positive charges from the negative, Kander explains. Polymer properties change with time, and they are studying those changes and the ways they affect PEM fuel cell performance.
In a related study, Kander, Nelson, and Don Leo, assistant professor of ME, are employing “smart” materials. “We’re trying to see if we can implant sensors in fuel cells to monitor the changes that take place in the proton-exchange membranes,” Kander says.
In collaboration with the American Society of Heating, Refrigerating, and Air Conditioning Engineers, Ellis is developing a guide to help building designers assess the opportunities for using fuel cell systems in buildings. Ellis, whose research background is in energy systems for buildings, says that only about one-third of the fossil fuel energy supplied to a typical power plant reaches houses and other buildings in the form of electricity. The remaining energy is discharged into the environment as waste heat.
Fuel cells convert about 40 percent of the input energy into electricity, with the remainder converted to heat, Ellis notes. Since a fuel cell system can be located on-site, heat from the system can be recovered and used for space heating or water heating. With both the heat and electricity available for useful purposes, fuel cells can reach overall efficiencies as high as 80 percent.
“Since fuel cells produce heat, the goal is to create a system that would supply heat, cooling, hot water, and power for a residence,” says von Spakovsky. Ellis and von Spakovsky, in collaboration with faculty members in the College of Architecture and Urban Studies, plan to develop such a system. It would need to produce 8 to 10 kilowatts of power and would be somewhat larger than a heat pump. With funding from United Technologies, Inc., von Spakovsky and Ellis are developing the tools needed to optimize the design of a system that could meet the needs of an individual home or a cluster of homes.
Other Virginia Tech faculty members collaborating on fuel cell research include Sean Corcoran of MSE, Jason Lai of electrical and computer engineering, and Uri Vandsburger of ME. Former Ph.D. student Benoit Olsommer, who recently completed post-doctoral work at Virginia Tech, developed a 3-D mathematical model of a PEM fuel cell that will be used in a number of research projects.
Virginia Tech researchers also are working with colleagues in Europe, von Spakovsky notes. The Swiss National Science Foundation partially supported Olsommer’s work. A graduate student from the University of Provence in Marseilles, France, is in Blacksburg using the finite element code developed in France to implement a part of the 3-D model developed by Olsommer. And researchers in Blacksburg and at the University of Zaragoza in Spain are collaborating on a study of fuel cell power production for residential and utility applications.
“Fuel cells have the greatest potential of any energy device for the 21st century,” von Spakovsky believes. “Only nuclear fusion could compete, but practical applications of that technology may be 50 to 100 years away. Fuel cells have the potential to solve immediate energy problems, to be one of the primary solutions to the problems of making fossil fuels less costly to the environment, and to increase the efficient use of these fuels.”
However, he cautions, there are no “silver bullets” to complex energy problems. “Fuel cells won’t be the only solution; they will play a major role in combination with other energy production developments.” Currently, for example, the leading technology for power utilities is combined cycles of gas turbines and steam turbines. “In the future, many utilities will join this technology with fuel cell systems for far greater efficiency,” von Spakovsky adds.
Kander points out another advantage of fuel cell use in transportation and power supply: the hydrogen necessary to power fuel cells can be obtained from several sources, including sea water. “Fossil fuel supplies are limited, but we don't have to use fossil fuels to produce hydrogen. In fact, we have access to an infinite supply of hydrogen to power fuel cells.”
The technology also will provide “portable power” in the future, von Spakovsky says. Fuel cells have been developed that can replace batteries in laptop computers, for example. Some have been made as small as transistors and can be used to power devices as small as wrist watches. However, as with larger fuel cells, the ones created for these portable power functions still must be custom-made and are not yet ready for mass production.
It will take at least 20 years, but fuel-cell-powered vehicles will become prevalent, Nelson predicts. By 2010, he says, a few will be produced for commercial sale, and by 2020 they will be a common sight on the highways “because the technology is so clean.”
“We’re already seeing the electrification of automobiles,” Nelson notes. “With electric windows, seats, heating and air conditioning, power steering, communications, and computer systems, the cost of electrical components will soon equal about 35 percent of the total cost of a car.” This electricity can be supplied by battery packs or a combination of batteries and engine power, “but someday it will be easier to use fuel cells to supply all electrical power.”
The future of fuel cell research at Virginia Tech also seems assured. “Numerous universities have fuel cell research programs,” says Kander, “but our interdisciplinary approach is unusual. Faculty members and students from materials science, chemistry, architecture, and several engineering fields are working together here.”
Von Spakovsky agrees that the interdisciplinary nature of fuel cell research at Virginia Tech is one of the program’s great strengths. “This group brings an extraordinary range of interests and skills to the advancement of this technology,” he adds. “We have the opportunity to become the premier university in fuel cell research.”