Fuel Cells Start to Look Real Fuel-cell technology

Unlike electrochemical batteries, which use chemical reactions to store and discharge electricity, fuel cells generate electricity from hydrogen fuel. Haul around enough fuel, and the fuel cell will power an electric vehicle as far as the motorist wants to drive.

The fuel cell was first demonstrated in principle by British scientist Sir William Robert Grove in 1839. Grove's invention was based on the idea that it should be possible to reverse the already well-known electrol­ysis process to produce electricity. In electrolysis, an electric current is introduced into a conducting liquid known as an electrolyte, where it flows between two electrodes causing the splitting of water or other chem­ical compounds into their ionic (charged) components, which then react chemically.

Many engineers believe that SOFCs (solid oxide fuel cells), together with an onboard gasoline fuel processor or reformer, would be highly suited as auxiliary power units (APUs) for cars and trucks in the rela­tively near term. Engineers have long desired to rid automobiles of the alternator and its notoriously low efficiency. And as vehicles are crammed with more and more electronic equipment and move toward higher elec­trical loads, a larger burden will be placed on the alternator. An auxilia­ry power unit based on SOFC technology could provide an ideal alter­native. A research alliance including BMW, Renault, and Delphi Auto­motive Systems is pursuing this fuel-cell application.

DaimlerChrysler, Ford, and their fuel-cell-stack development part­ner, Ballard Power Systems - the two automakers together own a third of Ballard and collaborate in a precompetitive development venture called XCELLSiS - have spent nearly a billion dollars on fuel-cell technology. Their current effort to mass produce fuel-cell cars and light-duty trucks over the next four years will cost billions more.

General Motors is making similar hefty investments in automotive fuel cells, while Japan's Toyota, Honda, Nissan, and Mitsubishi report­edly laid out close to a billion dollars on the new technology during the past decade. With an estimated-$6-8 billion having already been sunk into the fuel-cell industry, including both stationary and portable power types as well as transportation versions (according to analysts at Citibank), automakers are working to take fuel cells off the lab bench and move them onto the showroom floor.

Hybrid-electric vehicles

Another reason fuel-cell technology is favored is because it may be able to liberate electric cars from the electrochemical battery. While bat­teries are the cleanest automotive energy source, the technology is still highly problematic. And however responsive battery-powered electric cars are, their limited range and slow charging constrains them to a niche market segment, as GM's EV-1, Honda's EV-Plus, and other abortive electric car models have shown. Despite decades of research and invest­ment, electrochemical batteries simply haven't attained the power densi­ties needed for effective automotive propulsion power.

One way to extend the range of the electric car is to carry fuel and a small 1C engine onboard to generate electricity to power the electric drive-train. "Hybrids convert the problem of energy storage in a battery to one concerning the storage of fuel," explained Scott Staley, Chief Engineer for Fuel-cell Systems Engineering at Think Technologies, Ford's elec­tric-car enterprise. This hybrid-electric approach is employed in the re­cently introduced Toyota Prius and Honda Insight, which combine mod­est-size, high-efficiency combustion engines with batteries that supple­ment engine power during acceleration and hill-climbing, and recover energy from the brakes during stopping. Besides continuing to emit some pollutants, the combined electric and mechanical drives tend to make them complex and costly. Thus, automakers must subsidize current hy­brid car models heavily to make them affordable.

Nevertheless, because hybrid vehicles use proven technology that has yet to be fully optimized and refined, many experts believe they will pro­vide strong competition to fuel-cell-powered vehicles well into the fu­ture. A recent study by Massachusetts Institute of Technology research­ers concluded that hybrid-electric vehicles will be more common than fuel-cell-powered cars two decades from now. Indeed, the influential California Air Resources Board (CARB) recently reorganized its credit structure to emphasize hybrid-electrics as well as fuel-cell vehicles, while de-emphasizing battery-powered electric cars and trucks.

Whether fuel-cell-powered or any next-generation vehicles attain commercial success depends on three factors: technical feasibility (it must work), an appropriate fueling infrastructure (it must keep working), and customer acceptance (someone must buy it). Whereas the majority of today's efforts center on developing technical feasibility, in reality, all three factors are interrelated and interdependent. While the latter two issues remain unclear, it is evident that the three key elements must be developed in parallel.