Will Fuel Cells Zap the Energizer Bunny?
It wasn't long ago that futurists were predicting the ascendancy
of clean, quiet electric cars that would be plugged in at home
to recharge. A new version of the future turns that scenario upside
down: The house plugs into the car and draws whatever power it
needs from the vehicle's engine.
It's not such a crazy idea. Most people don't realize it, but
making a car go takes much more energy than powering everything
in the typical house. If cars ran on a more efficient, nonpolluting
system such as fuel cells instead of by the combustion of gasoline,
they could quietly and safely generate all the electricity a house
needed from the garage. (Batteries would be needed to take over
when the car was away.)
Many practical problems need to be overcome before fuel-cell
cars can double as home power plants. A team of researchers led
by Paul McGinn '80, '83M.S., '84Ph.D, Notre Dame professor of
chemical and biomolecular engineering, is trying to solve some
of them.
The researchers are actually working under a grant from the
Army, which has its own vexing power problems. Today's military
relies on an array of electronic communications equipment, global-positioning
targeting instruments and other devices, most powered by batteries.
During the conflict in Iraq, military planners found that soldiers
in the field depleted batteries in their high-tech gadgets faster
than fresh supplies could be delivered.
Fuel cells promise longer-lasting, easily replenished power.
Like batteries, they generate DC current through a chemical reaction.
In the fuel cell, it's the reaction between hydrogen gas and a
catalyst, usually platinum. The reaction ends with hydrogen gas
combining with oxygen from the air to produce a nonpolluting exhaust
-- water vapor. As long as the hydrogen keeps pouring past the
platinum catalyst, the reaction keeps producing electricity and
water vapor.
It sounds like a great system, which is why it has received
so much attention lately, including a proposal by President Bush
in his 2003 State of the Union address to spend $1.2 billion on
fuel cell development.
Unfortunately, even the most advanced cells of today are too
heavy and expensive. An engineer at the University of California
Berkeley has estimated that a fuel cell powerful enough to run
a car today would cost $300,000.
One of the objectives of McGinn's research is to find a cheaper
substitute catalyst for expensive platinum. In case there isn't
one, he's also exploring ways to reduce the amount of platinum
needed. As the engineer points out, "There has not been enough
platinum mined [in all of history] to run all the cars in the
United States at the present levels of platinum loading."
The most formidable stumbling block for fuel cells, though,
isn't the scarcity of platinum but of hydrogen. Paradoxically,
the element is the most abundant in the universe, but on earth
it's all bound up with other elements, as with oxygen in water.
Separating out hydrogen from these compounds takes a lot of energy.
And if the energy to do this comes from fossil fuels, not much
will have been gained in terms of energy and reducing pollution.
McGinn says he's optimistic that many of the problems of fuel
cells can be overcome and that the technology can at least be
integrated such with alternative energy sources as solar and nuclear
power. But like other researchers, he sees the growing euphoria
over fuel cells as premature.
"Everyone sees fuel cells as this panacea, which they may not
be."
