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February 15, 2005
The Fundamentals of Fuel Cells
Before we can zip around in zero-emission fuel-cell cars, the technology has to clear several roadblocks. Here's how fuel cells work, how they're being improved, and how long it will take before they hit the mainstream:
What's the big deal?
Fuel cells have grabbed headlines and R&D dollars because they promise to ease pollution and petroleum consumption. A clean and quiet power source, fuel cells could someday power homes, cars and electronic devices more efficiently and with less pollution than conventional sources. They can run on pure hydrogen--a clean and abundant fuel--and release only water as a byproduct.
What are they exactly?
BusinessWeek recently likened fuel cells to tiny "chemical refineries." These electrochemical energy conversion devices form water from hydrogen and oxygen and in the process, generate 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.
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.
Brief history
In 1839, Sir William Grove combined hydrogen and oxygen, forming water and generating electricity. Today, fuel cells still work in essentially the same way. Their basic configuration consists of "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," says Fuel Cell Today.
The U.S. government has been researching the benefits of the technology for more than half a century--with varying degrees of interest. After initial development, fuel-cell technology was largely ignored, overshadowed by the advent of the internal combustion engine and hindered by its limited practical application. But now, it has received renewed attention because of its environmental benefits and energy-saving potential.
Stumbling blocks?
Despite some inroads, mainstream use continues to elude fuel cells because of their high cost. According to a recent BusinessWeek article, "a fuel-cell system powerful enough for a car would add roughly $100,000 to sticker prices today." Also tricky: storing and distributing hydrogen. An infrastructure of hydrogen refueling stations is a must, but less than 100 filling stations around the world supply hydrogen so far, according to BusinessWeek.
To address the hydrogen issue, a device called a reformer is usually employed. It converts 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 greatly reduce the fuel cell's efficiency--a huge issue for powering vehicles.
Meanwhile, when in comes to providing energy for portable products, tiny fuel cells have to tackle several critical issues, says a recent Design News article. These include standardization, energy density, and methanol crossover, says Sara Bradford, a Frost & Sullivan analyst.
On the bright side...
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 this year.
Meanwhile, to boost efficiency, some firms are forgoing the reformer entirely by developing advanced storage devices for hydrogen. Also, much progress has been made in increasing the fuel cell's power density through engineering and material advances. Today, fuel cells can pack more power in smaller spaces. Now a device no bigger than a compact piece of luggage can run a car.
Forecast
According to Design News, this year will mark the "coming-out party" for micro fuel cells in portable products, such as laptops and industrial mobile-computing devices. But we may have to wait a couple of decades before fuel-cell cars can become mainstream enough to help reduce pollution or our dependence on petroleum, says BusinessWeek.
Sources:
Micro Fuel Cells: A Coming-Out Party in 2005
Randy Frank
Design News, January 10, 2005
www.designnews.com/article/CA491477.html
Hydrogen Cars Are Almost Here, But...
Otis Port
BusinessWeek, January 24, 2005
www.businessweek.com
How Fuel Cells Work
Karim Nice
How Stuff Works
auto.howstuffworks.com/fuel-cell.htm/printable
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19 CommentsVehicle propulsion gets a big chunk of the attention when it comes to emissions and air pollution but the experts say manufacturing creates more. I would say we have not utilized or exhausted options in automotive fuel and lubrication to warrant the fuel cell option. Car, truck and truck fleet owners have let themselves be prostalyzed by mega petroleum oil manufacturers without looking for the more cost effective synthetic lubricants that are cleaner and better. Most car oil brands have made significant strides in offering the consumer a product with more synthetics but only enough to meet the minimum criteria. The 3,000 or 5,000 mile oil change interval is a deterrent to not educate the owner to spend less money. If it where up to me, I would educate all car, truck and equipment owners they do have options that are cleaner, and less polluting than using petroleum based lubricants.
February 15, 2005 5:39 PMR.Hiebert comments were well taken. Especially in regards to stationary energy sources. And maybe I am not up on fuel cells as much as I should be but if I was to bet on something it would be the point of use of hydrogen production. IT is unbelievable what a few volts and a glass of water and two electrodes can produce. The shear sound of one exploding bubble coming off the top of a drinking glass make the mind race with anticipation of the real world possibilities. I also find it interesting that carbon nanotubes have such a similar charterestics in its cross section to hydrogen. And in as much as it capabilities to store hydrogen inside of its structure. Evolution does take time yet as does wisdom, yet one might consider the direction of our quest.
The thing about hydrogen as a fuel that gets very little attention is that it takes more energy input to seperate hydrogen from water by electrolysis than is recovered by burning hydrogen as a fuel, even though strides have been made in making the process more efficient. http://newsdesk.inel.gov/press_releases/2004/11-29hydrogen_production.htm Seperating hydrogen from hydrocarbons does not solve the problem of what to do with the gasses remaining after the seperation. These are effectively polutants. Also the political/economic problems associated with dependance on petroleum as a source are not solved. Very little is being said about using the megawatts of electricity available at nuclear power plants and the enormous waste heat energy at those facilities to seperate hydrogen from water by electrolysis right on the site. What am I missing?
February 16, 2005 7:58 AMI agree with Wayne Martin that "very little attention" is being paid to the fact that currently "it takes more energy input to (create hydrogen) than is recovered by burning hydrogen as a fuel." Of course, this should not impede research into this exciting technology even if it never becomes practical for powering homes or automobiles. If nothing else, the threat of hydrogen powered automobiles has spurred the automotive/truck industry to continue/step-up research into more fuel efficient vehicles, particularly diesel power. And, of course the emissions issues, whether considered fairly or not, with respect to fuel cell technology may well kill the technology for widespread power useage just as it did nuclear power in this country. However, I look forward to continuing fuel cell development that will allow me to use my laptop computer, cell phone, and the like for a month or a year without having to recharge the battery or be connected to an outlet.
February 16, 2005 9:57 AMWayne Martin and Don Shrader hit on the issues of concern to me. What good does it do if we eliminate pollution at the fuel cell, but continue to create pollution in the process of separating out the hydrogen? And, of course, the question of energy efficiency of the process when we use more energy to create hydrogen than we can extract from the fuel cells. I believe that the obvious choice for a source of hydrogen would be water; extraction of hydrogen from water leaves oxygen with no other polluting by-products. How do we get the energy to separate the hydrogen out of water without the energy production causing pollution? Solar energy is an obvious choice. It's clean, "free" and abundant. The issue here is the technology to economically extract that "free" solar energy. To be successful, the entire process of hydrogen production to fuel cell usage must be affordable.
February 16, 2005 12:45 PMHydrogen/oxygen fuel cells aren't the only option. They get the most research dollars. The underlying problem is that the hydrocarbon fuel industry is huge. They exert a lot of influence to channel fuel cell research into areas that will still require the consumption of the hydrocarbon fuels they supply. Metallic Power (in Carlsbad, CA) was developing zinc/oxygen fuel cells. These used zinc pellets and oxygen from the air. They were working on an efficient way to plug the cell into the electrical grid (a wall plug)and reverse the process. The result would be a system that took zinc pellets and air as an input, generated electricity by oxidizing the zinc, could be plugged in to "charge" (i.e., regenerate pure zinc pellets by using electricity to drive the oxygen back into the air), and could operate back and forth like this for many cycles. Metallic Power closed their doors last year. There is very little interest (in this country) to develope a fuel cell technology that replaces hydrocarbon fuels. The driving force appears to be to get rid of the internal combustion engine, but make sure we keep the fuel supply industry.
February 19, 2005 11:12 PMThe problem with hydrogen is that it is an intermediate energy storage mechanism / device; it is not a source of enery. It must be created from other energy sources such as HC's, or nuclear to electrolysis of water. Unlikes HC's buried in the ground, deposits of hydrogen do no exist.
March 3, 2005 11:44 AMAbout 3 or 4 years ago (2001-2002) I read in a Seattle newspaper or the Seattle NBC affiliates news internet site, where Honda had developed & was showcasing on the West Coast (Washington State), a fully functional fuel cell prototype automobile. It utilized a body that was cover in solar cells. The solar cells were the catalyst to remove Hydrogen from ordinary tap water, which in turn fueled the engine. Did anybody else hear about this & if so, what happened to this inovation. There seemed 2 B a lot of hype regarding it, but I never heard of it again. Could the oil industry be putting the quietist on things like this???? Always on my mind.
April 4, 2005 4:44 PMWhy are zinc pellets any different from batteries (at Fred Hunt's comment)
It seems to me like obtaining hydrogen from fossil fuels or electrolysis will not raise the efficiency level very much at all. What about the use of bacteria? Fermentation or something? Alcohol has quite a lot of energy.
January 16, 2007 12:15 PMhow regenerate zinc from zinc oxide?
April 28, 2008 5:59 AM
