We’ve all heard the hype. Now discover how fuel cells actually work and how fuel-cell cars really compare with gasoline cars. Also, learn the technology’s history and its future markets.

Because they are a clean and quiet power source, fuel cells are fascinating to many people. And to industry, they represent an extremely promising technology that could someday power homes, cars and electronic devices more efficiently and with less pollution than conventional sources.

But what is a fuel cell exactly? It’s an electrochemical energy conversion device that forms water from hydrogen and oxygen and in the process, generates electricity and heat. Providing a DC (direct current) voltage, a fuel cell basically operates like a battery that can be recharged while it is generating power.

Despite some inroads, mainstream use continues to elude fuel cells because of their high cost. In fact, while the fuel-cell market is still considered relatively new, the U.S. government has actually been researching the benefits of the technology for more than 50 years. And if you trace the technology’s history, you’ll have to go back even further than that—to 1839, the year it was discovered.

That year, Sir William Grove combined hydrogen and oxygen, forming water and generating electricity—still the basic configuration of fuel cells today. Several different types of contemporary fuel cells follow a central fuel cell design, which is described by Fuel Cell Today as “two electrodes, a negative anode and a positive cathode, which are separated by a solid or liquid electrolyte that carries electronically charged particles between the two electrodes.”

After initial development, fuel-cell technology was largely ignored—pushed aside by the advent of the internal combustion engine and hindered by its limited practical application. But now, it has claimed center stage, with President George W. Bush introducing a $1.7 billion hydrogen initiative and urging companies to invest in the alternative energy source because of its environmental benefits and energy-saving potential.

To go mainstream, fuel cells will need to outperform many other types of energy conversion devices, such as gas turbines in power plants, batteries in laptops, and gasoline engines in vehicles. As this list of competitors suggests, fuel-cell markets fall under three general categories—1) stationary (generators), 2) portable (electronic devices such as laptops, cellular phones and hearing aids) and 3) vehicle propulsion.

There are a number of different types of fuel cells—some of which show promise for one or more of these markets. For example, the proton exchange membrane fuel cell (PEMFC) is the prime candidate for powering cars, buses and perhaps homes. Meanwhile, the phosphoric-acid fuel cell (PAFC) fits in small stationary power-generation systems and is ill suited for cars because it takes a long time to warm up.

In terms of competitive pricing, stationary power fuel cells will likely break into the market first, followed by cells for portable power generation, says Gregory M. Stoup, acting director at the Cleveland-based Center of Regional Economic Issues, Case Western Reserve University.

Fuel cells have several formidable obstacles to overcome in their quest for market penetration, including their high price and manufacturability. While Stoup notes that the technology’s price in terms of power generation, distribution and storage has started to close in on that of other alternative energy sources, another industry observer points out that the question of manufacturability has been overlooked almost entirely.

“It’s our observation that the vast majority of research and development expenditures on fuel-cell technology have been devoted to the physics and chemistry on how the fuel cells work and how to make them work better,” says Stan Ream, automotive market leader at the Edison Welding Institute (EWI), an Ohio-based non-profit focusing on materials-joining technology. “The issues of manufacturability have been left pretty much unaddressed. Many of them are not designed for manufacturability.”

Another issue revolves around fuel cells’ need for hydrogen. While oxygen can be extracted from the air, hydrogen is hard to store and distribute, requiring the development of an infrastructure of hydrogen refueling stations. This is where a device called a reformer comes in, converting hydrocarbon or alcohol fuels into hydrogen, which then enters the fuel cell. Reformers are problematic, however, creating heat and producing other gases along with hydrogen. Although several devices can help reformers clean up the hydrogen, they still produce impure hydrogen and reduce the fuel cell’s efficiency.

Fuel cells can extract hydrogen from such fuels as natural gas, propane and methanol. Many homes are already equipped with natural-gas lines or propane tanks so these fuels are very promising for home fuel cells. Meanwhile, methanol, a liquid fuel, can be easily transported and distributed—making it a contender for fuel-cell cars. In fact, for small fuel cells for electronic devices, methanol is already being positioned as the fuel of choice. Such micro fuel cells are set to debut on the market in two to four years.

Fuel cell efficiency is yet another concern, especially for powering vehicles. This is because the whole fuel cell system figures into the efficiency equation. While using pure hydrogen yields a fuel cell efficiency of up to 80% (that means 80% of hydrogen’s energy content can be converted into electrical energy), we have noted that reformers are usually required and they lower overall efficiency to about 30-40%.

And that’s not all. The electrical energy still needs to be converted into mechanical work—a task that is performed by the electric motor and inverter, which is roughly 80% efficient. So considering the 30-40% efficiency of generating electricity using a reformer and the 80% efficiency of turning the electricity into mechanical power, the fuel-cell system can only claim a total efficiency of about 24-32%. What’s more, that’s not significantly above the efficiency of a gasoline-powered car, which is roughly 20%. (Remember that gas engines waste all of the heat that gets released as exhaust or travels into the radiator. And such engines also consume a lot of energy rotating the requisite pumps, fans and generators.)

Many companies are scrambling to address these fuel-cell issues. Some firms are forgoing the reformer entirely by developing advanced storage devices for hydrogen. Also, much progress has been made in boosting the fuel cell’s power density. Because of advances in engineering and in the materials used, fuel cells can pack more power in smaller spaces. Now a device no bigger than a compact piece of luggage can run a car.

And of course, there are the previously mentioned micro fuel cells, which are considerably smaller than their car counterparts. Pioneering companies like Neah Power Systems, a Washington-based micro-fuel-cell development company, and MTI MicroFuel Cells Inc., a New York-based subsidiary of Mechanical Technology Inc., are looking to power a range of products with such small devices.

Neah, for example, is taking aim at notebook PCs, advanced communications gear for the military, and logistical applications for warehouses. “If you think about a fuel cell, it’s really very similar to a sophisticated disposable battery—except the run time is much longer,” says Dave Dorheim, Neah president and CEO. Meanwhile, MTI Micro plans to make fuel cells for industrial mobile-computing devices, such as PDAs for scanning and tallying up inventory in warehouses. The company is also working with another firm to develop fuel cells for use in military radios.

Such companies acknowledge, however, that while the technology’s potential is without question, approaching the market will require a great deal of strategizing. Says William Acker, president and CEO of MTI Micro, “We recognize that you can have the best technology on earth, but if it’s not introduced properly—in terms of price and usability—the industry will not come alive.”

Sources: How Fuel Cells Work
Karim Nice
How Stuff Works
http://auto.howstuffworks.com/fuel-cell.htm/printable

Our Fuel-Cell Future
Traci Purdum
Industry Week, April 1, 2003
http://www.industryweek.com/currentArticles/asp/articles.asp?ArticleId=1405