Saturday, April 29, 2006

UW prof probes hydrogen fuel cells, energy diversity for cars

WATERLOO, Ont. (March 6, 2006) -- As the world hits peak oil production, there is keen interest in finding the next great fuel source. Many hope that hydrogen can be harnessed and that by the end of the 21st century we will all be driving hydrogen-powered cars.

Ironically, that's not the hope of Xianguo Li, a professor of mechanical engineering at the University of Waterloo and a hydrogen fuel cell researcher. Though his research is focused on improving hydrogen fuel cells so they could be used in everybody's car, he doesn't want them to be the sole option.

Instead, he espouses the notion of diversity. "The second law of thermodynamics, in essence, states that every energy process has an impact," said Li. "Biomass, solar, wind, hydrogen, if any of these took a dominant position in the market they would have major disadvantages."

Li cites the example of London or Paris 100 years ago. Large cities at the turn of the 20th century had a major problem: everyone used carriages pulled by horses to get around and that meant there were horse droppings everywhere. At a time of poor sanitation and street infrastructure, that led to a lot of disease not to mention the smell.

Then, a novel device known as the automobile came along. It ran on oil, which was in vast supply throughout the world, and best of all the only thing it released was a little smoke that vanished into the air. Perfect solution, right?

Only a few decades later we learned in a hard way -- like the Los Angeles smog -- that it was not perfect, after all. By now we know how the car has changed society and created several large problems.

Li believes the same would be true if hydrogen dominated the energy market. "Often, in history, we hail a new technology as a major step forward, but only to realize its horrible side effects later, and we had to spend tremendous effort to eradicate those effects. It all comes back to the principle that you can't get something for nothing."

Instead of one energy source dominating, Li believes the answer is energy diversity and that hydrogen fuel cells can play a large part, such as for automobiles in urban areas.

The mechanical engineering researcher has been working to make hydrogen fuel cells less expensive, more reliable and more user friendly. "The real world is not kind to cars like labs are, so we have to design better and robust engines that can be easily made and maintained."

One of the ways that the life and reliability of hydrogen fuel cells could be improved is through optimizing how many fuel cells are in operation at any given moment. Not as much power is needed for idling at a red light as for cruising at 100km/h, so Li's research team is developing a technique that can determine how many cells need to be activated depending on energy needs.

As well, one of the major challenges with hydrogen fuel cells is allowing the transfer of electrically charged particles between electrodes. To do that, an electrolyte (fully humidified with water) is needed to facilitate the movement. However, all the water moves to one electrode, drowning that side and leaving the other in drought.

Li's team is attempting to use the natural humidity in the air plus some of the water produced during the electrochemical reaction to keep the energy flowing evenly.

But one of the largest concerns for Li's research is its use in the real world. Currently, hydrogen is not easily available since it is classified as a chemical not a fuel source. If that changes then it is possible that more hydrogen refuelling stations will appear.

In fact, the various levels of government are encouraging hydrogen growth with various initiatives, including the support and planning of a "hydrogen corridor," a series of refuelling stations along the 401 Highway so hydrogen-powered vehicles can go almost the length of the province and beyond.

As hydrogen technology develops and gains acceptance in consumers' minds, Li hopes that people will temper the desire to use it everywhere with the knowledge that all energy systems have negative impacts. "If we use any energy on a worldwide scale, there can be lots of problems, but if we use it on a small scale we should be okay."

(Written by Graeme Stemp-Morlock, SPARK -- Students Promoting Awareness of Research Knowledge -- writing program.)



Post a Comment

<< Home