What are fuel cells?
Fuel cells are devices for generating electric power. They share
many of the characteristics of a battery - silent operation, no
moving parts and an electrochemical reaction to generate power.
However, unlike a battery, fuel cells need no recharging and will
run indefinitely when supplied with fuel. The cells produce
electricity by combining hydrogen (the fuel) and oxygen (from air)
over a catalyst such as platinum.
There are several different types of fuel cell but the most researched
type is the proton exchange membrane (PEM) fuel cell, which
contains platinum catalysts. PEM fuel cells are capable of being
used in power generation for buildings, instead of batteries or
generators in portable equipment and as replacements for the
internal combustion engine in a vehicle.
Fuel cells for transport
In 1997, Daimler-Chrysler, Ford and Ballard Power
Systems joined together in a consortium to build fuel cell
engines and drive trains for cars. DaimlerChrysler, Ford,
Honda and Toyota now have small demonstration fleets of cars in
operation. A total of 30 fuel cell buses built by DaimlerChrysler
and Ballard went into service around Europe in 2004. This
project was designed to demonstrate the technology and increase
public awareness of fuel cells.
In 2009, six major automakers - Toyota, Hyundai, Daimler AG,
Ford Motor Company, General Motors Co. and Honda - signed a
memorandum of understanding to develop fuel cell light duty
vehicles and encourage introduction of the necessary hydrogen
infrastructure. These companies plan to commercialise fuel cell
vehicles by 2015 and are tareting key locations, such as Germany,
Japan and the USA, for infrastructure development allowing the
rollout of fuel cell vehicles.
Why fuel cells for vehicles?
The advantages of fuel cells for transport are both
environmental and economic. The only emissions from a fuel cell
vehicle come from the generation of hydrogen. Fuel cell cars
have similar range and performance to cars with internal combustion
engines, but the superior energy efficiency of fuel cell engines
brings a significant reduction in carbon dioxide, a greenhouse gas,
for every mile travelled. If fuelled directly by hydrogen, there
will be no tailpipe carbon dioxide emissions at all.
Fuel cells for stationary power
Fuel cells can also provide electric power for
homes and offices. In these applications, heat produced by the
cell can be circulated like the heat from a conventional boiler.
Using the combined heat and power in this way considerably raises
the efficiency of the system. More than 10,000 such units are
already in use in Japan, the USA and Europe to power hospitals and
industrial plant and to provide grid-independent, uninterrupted
Portable fuel cells
Fuel cells can compete with batteries and generators for portable use, from a few kilowatts to power a
mobile home down to a few watts to power a laptop computer.
Methanol fuel cells designed to provide ancillary power to camper
vans and boats are selling commercially and hydrogen-fuelled
external charging devices for consumer electronics became available
Fuels for fuel cells
Hydrogen to run the fuel cell can be
stored as a compressed gas, as a liquid or in a chemically-combined
form, such as a metal hydride. It can also be produced
by reforming a hydrocarbon such as gasoline, methanol or
natural gas. For transport, high pressure hydrogen storage and
delivery has been developed to allow vehicles to refuel at
conventional filling stations.
Barriers to fuel cells
Today the biggest obstacle to fuel cell commercialisation is
cost. Research is being focused on improving cell performance and
developing low cost materials which will enable fuel cells to
compete on price: at first against batteries and later against
conventional engines and generating plant.