While fuel cells may hold promise as a source of energy in the future, much needs to be accomplished before their potential is realized.
Institute Professor John Deutch made that point on Wednesday, March 12, in a talk on "Fuel Cell Applications" in Wong Auditorium. The session was sponsored by the Laboratory for Energy and the Environment.
"I believe fuel cells will become an important part of the energy picture of the United States, but it will be a technological challenge to make it so," Deutch said. "Each problem [facing fuel cells] requires a half-dozen innovative MIT students to solve it."
A fuel cell is like a battery that never needs recharging. It consists of two electrodes sandwiched around an electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat. There are several types of fuel cells, but only the alkaline fuel cell--used as a power source in space--is practical and cost-effective.
A fuel cell for a car can use hydrogen produced from any hydrocarbon fuel, but no cars have been designed with on-board reformers to make their own hydrogen. The hydrogen has to be supplied from methane, natural gas or petroleum, but because the fuel cell relies on chemistry and not combustion, emissions from this type of a system would still be much smaller than emissions from the cleanest fuel combustion processes.
While fuel cells are more efficient, simpler, cleaner and quieter than other energy sources, they are not yet cost-effective and their reliability for use in transportation has not been proven in the long term.
At the moment, advanced internal combustion engines have an edge in efficiency over fuel cells, Deutch said. If everyone switched to a hybrid vehicle such as the Toyota Prius, Americans could significantly cut their consumption of petroleum products.
The solid oxide fuel cell, which operates at elevated temperatures, is most promising for future use, Deutch said. He believes this system, which would be a large-scale, stationary power source for buildings, could be economically attractive. Producing advances in fuel cell technology requires expertise from fields including chemistry, mechanical and electrical engineering, materials science, economics, system design, and modeling and simulation, Deutch said.
Because the problems fuel cells present are so interdisciplinary, Deutch said, they are a perfect teaching tool. "More research on fuel cells should be going on at MIT," he said.
A version of this article appeared in MIT Tech Talk on March 19, 2003.