Frequently Asked Questions: Fuel Cells
What is a Fuel Cell?
Essentially, it is a re-fuelable "battery", as opposed to an electrochemical one that is recharged.
Unlike a regular rechargable battery that can take hours to recharge, a fuel cell can be re-fueled in
minutes, which is its principle advantage when it is used to power an electric-drive vehicle... or laptop computer.
Hydrogen gas -- or a hydrogen-rich fuel like methanol -- is fed into the fuel cell stack, which consists of a series of
individual cells tightly packed together. Within each cell, the hydrogen atom loses an electron as it migrates
across a specially-coated plastic membrane, creating a current potential that can be tapped to do work like run an
electric motor. While the voltage of each cell is rather small, "stack" enough cells together and it will generate
sufficient electrical voltage and current to power an automobile.
Will Fuel Cell Cars Someday Replace the Internal Combustion Engine?
Very likely, yes. But there are many important issues, both technical and economic, that
must first be resolved. The advantage of a fuel cell over the internal combustion engine largely is one
of efficiency and emissions. At best, a typical gasoline engine is about 25% efficient, with most of the
energy potential of the fuel being lost to heat and friction. Fuel cells are approaching 40% efficiency and
demonstrating fuel economies equivalent to between 45 and 70 miles per gallon. Because it electrochemically
converts the energy stored in hydrogen rather than combusts it, it produces no harmful emissions, only
low-grade heat and water vapor. And, best of all, a fuel cell-powered vehicle is virtually indistinguishable in performance from its IC-engine
counterpart.
When Can I Expect to Buy One and For How Much?
It is likely to be sometime after 2015 before fuel cell automobiles will become commercially available in significant
numbers, assuming cost and fuel infrastructure issues are solved. To demonstrate the feasibility of
fuel cell-powered cars, Honda and GM are embarking on programs to make their latest models available to consumers
starting in 2008. Honda will offer its FCX Clarity fuel cell sedan for lease within specific zip codes in the greater
Los Angeles area, extending an earlier program. GM will loan some 100 of its Equinox fuel cell SUVs to consumers
as part of its Project Driveway program. As to how much a fuel cell vehicle will cost, it will have to be
priced competitively with its competition at the time; in all probability, the IC-engine equipped plug-in hybrid,
early versions of which are demonstrating average overall fuel economies of 75 mpg, when local electric utility
rates are included.
Fuel cells are likely to show up first in portable consumer electronics as replacements for batteries in
laptop computers and cellphones. Micro-fuel cells that use hydrogen-rich methanol to generate just a few
watts of energy have already been approved for use on commercial jetliners and are slated to
hit the consumer market before 2010. They will enable consumers to run their laptops for upwards of 20 hours
before needing to be refueled, a process that is likely to involve replacement of a disposable methanol cartridge.
The first commercially-affordable fuel cell-powered vehicle applications for consumers could be in two-wheelers like electric bicycles or
motor scooters. Several companies have already demonstrated prototypes, but again the vehicle will have to be
competitive with its competition: battery-powered and gasoline-powered models.
