Posted: February 2, 2008

Is hydrogen for airheads?

(Nanowerk News) As Korea pushes into the so-called hydrogen economy, the nation as a whole could be likened to children in the back seat of the family car, asking their parents over and over as each landmark is passed "are we there yet." The answer is not yet -- not even close, though milestones are flying by at a faster clip.
From the year 2000, when Hyundai introduced a fuel-cell powered Santa Fe SUV, to the opening of the nation’s first hydrogen fuel "gas station" last September, hydrogen has been praised as a potential savior in a world endangered by energy shortages, climate change and oil politics. Hydrogen is the most abundant element in the universe, and it is clean burning. But hydrogen, particularly in fuel cells, still poses daunting hurdles.
The one challenge that keeps advocates of hydrogen fuel cells working hardest is this: Fossil fuels are processed to acquire the gas. Thus, environmental gains are lost because the acquisition process requires burning fossil fuels in chemical reactions that blanket the globe with climate changing carbon emissions.
Lee Pil-ryul, a professor at Korea National Open University, holds a hydrogen economy as nonsensical. How can hydrogen be a clean option when producing it requires the same fossil fuels it is supposed to replace?
Korean scientists are working on this problem at the National Organization for Hydrogen and Fuel Cells. Its overall goal is clear: Develop hydrogen-based industry.
The fuel cell, the core technology in this endeavor, has been around since 1839 but has never met lofty expectations. Close up, the fuel cell looks like a winner, combining hydrogen and oxygen to produce electricity, and emitting only water. But they are expensive, with one estimate putting the cost of a fuel cell that provides 100 horsepower to an automobile at half a million dollars.
Add to this the fact that a car can go much further on a tank of gasoline than on a fully charged fuel cell. Take a wider view and two other problems enter the picture: storage and transportation.
A network of pipelines, trucks and filling stations moves gasoline easily to where it is needed, which is a factor in its continuing market viability despite rising oil prices. Hydrogen can be moved around, but with great difficulty. It corrodes pipes so thousands of hulking trucks hauling pressurized containers of the highly explosive gas will be necessary. And who would want a tank of hydrogen five times as big as a gasoline tank in their personal vehicle? Right now such a hydrogen network would entail unacceptable dangers and be very much more expensive than distributing gasoline.
But if a fuel cell could be developed that competes favorably with the internal combustion engine, the incentive would exist to solve the infrastructure problems.
Ernest J. Moniz, professor of physics and engineering at Massachusetts Institute of Technology has outlined a scenario where hydrogen fuel cells are used on a large scale for transportation. At the very top of the list of problems is where to obtain the hydrogen. Two options – natural gas and water – are appealing because of their abundance. Both, however, would be hugely prohibiting in terms of paying for the quantity of natural gas needed or paying for the energy required to drive the reaction to free hydrogen from water.
Hong Seong-ahn, head of research at the National Organization for Hydrogen and Fuel Cells, agrees that hydrogen must come from fossil fuels, but that this would be only in the early stages of a hydrogen economy. Fossil fuels would eventually be phased out, he says.
The approach at the fuel cell national organization is for nuclear power to provide the hydrogen supply – cheaply. According to the organization’s plans, by 2040 most of the hydrogen used in Korea will come from nuclear power plants. But according to Moniz, the cost will be high and the technology is not proven. And even with an abundance of hydrogen, completing the puzzle requires effective storage and efficient use.
Materials science, an area Korea has earmarked as vital to the nation’s economic development, might hold the solution. Professor Ihm Ji-soon of Seoul National University’s School of Physics and Astronomy has developed a titanium compound that stores hydrogen as a solid, which by eliminating pressurized tanks, could reduce the cost and safety hazards of hydrogen vehicles.
Nanostructures – materials on the order of one billionth of a meter – exhibit properties that can boost the chemical reactions that result in more efficient hydrogen applications. Every aspect of the hydrogen picture involves a catalyst, whether it is production, storage or end use, says Mildred Dresselhaus, professor of physics and electrical engineering at the Massachusetts Institute of Technology. Highlighting the growing importance of this research, last August the Fourth U.S.-Korea Forum on Nanotechnology, which addressed sustainable energy, included presentations on hydrogen storage and production.
Fuel cells do not compete with gasoline engines when subjected to market scrutiny. They are getting closer but critics are convinced they will never be practical. A giant leap in technology is needed to make them viable on a scale way beyond the demonstration vehicles that are making the news. Korean materials scientists are betting that their discoveries will make the much-doubted fuel cell a transportation killer app.
Source: (Arnold Stockard)
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