Scientists Question Hydrogen Fuel Cells

Yahoo News-AP Science ^ | September 08, 2003 | AP Science Staff

[PeaceBeWithYou]

LOS ALAMOS, N.M. - Hydrogen fuel cells may not be the most environmentally friendly answer to America's dependence on foreign oil, according to a study led by a Los Alamos National Laboratory scientist.

Los Alamos researcher Thom Rahn headed a team of scientists from California universities and the National Center for Atmospheric Research in Boulder, Colo. Their study of the natural cycle of atmospheric hydrogen was published in a recent edition of the British science journal Nature.

While there are certain benefits to hydrogen power, Rahn said there may also be unforeseen consequences that need to be examined before the energy technology replaces fossil fuels.

The reason scientists were interested in hydrogen's natural cycle was "because there are possibilities of perturbations in the future," especially if humans start producing a lot of hydrogen, Rahn said.

Proponents of a hydrogen-based economy powered by fuel cells argue the technology could reduce smog by replacing traditional fossil fuels and produce more efficient engines. Fuel cells convert hydrogen into electricity and heat.

Production of hydrogen near the Earth's surface could also damage the highest region of the atmosphere, or stratosphere, if escaped hydrogen accumulated, Rahn said. The hydrogen buildup could deplete the ozone layer near the earth's poles and increase global warming (news - web sites), he said.

"It is impossible to manufacture, store and transport hydrogen without at least some fractional loss (to the atmosphere)" because hydrogen molecules are so small and lightweight that they are tough to contain, he said.

Rahn and other Los Alamos researchers are studying how the atmosphere might respond to increased hydrogen and are establishing a baseline for further comparisons.

The atmospheric effects of hydrogen are similar to those produced by chloroflurocarbons, or CFCs, which have been used as refrigerants and aerosol propellants, he said.

"Everyone thought that (CFCs) were innocuous and nonreactive, and they were in the troposphere, but not in the stratosphere," he said.

In the stratosphere, CFCs contribute to the depletion of the ozone layer that protects the planet against harmful ultraviolet rays.

Rahn said more hydrogen may make it easier for some chemicals already present in the stratosphere to eat away at the ozone and contribute to global warming by increasing the amount of water vapor in the upper atmosphere.

Los Alamos atmospheric scientist Manvendra Dubey, who heads Rahn's research group at the lab, said hydrogen technology holds great potential for cleaner air and more efficient engines although more study is needed.

"With every new technology you have inadvertent consequences," Dubey said.

[PeaceBeWithYou]

I have been waiting for the environuts to come out with this ever since the President endorsed Hydrogen Fuel Cell technology.

Ozone does indeed react with Hydrogen(and lots of other elements too), and it is the lightest of all elements, but most if not all of it would react with something else long before it reaches the Stratosphere.

Also, Ozone is a product of ultraviolet light and Oxygen. Oxygen is our protection from UV light, not Ozone.

[PeaceBeWithYou]

Ping.

[sleepy_hollow]

You've got it right.

Hey, I've got an idea! Why not build a model like the one they used to see if the space shuttle was damaged at lift off? We could feed that model all kinds of garbage data and then use the results to substantiate any claim we want to make. Anyone who disagrees with us will be branded as ignorant unsophisticates.

By the way, that polar ozone hole thing has always bothered me. How do we know the holes were created by our chemicals? Who has been measuring those things and for how long? Cannot have been more than a small interval of time relatively speaking.

[Marauder]

I have been waiting for the environuts to come out with this

Yup, me too. It didn't take long to see the old fruitcake global warming crap once I started reading the article.

It amazes me that anyone even listens to these liberal crackpots.

[RightWhale]

because hydrogen molecules are so small and lightweight that they are tough to contain, he said.

Are they smaller than, say, oxygen molecules? Don't want to crapcan the article before knowing this vital fact.

[mtbopfuyn]

So, what was the cells' answer?

[Britton J Wingfield]

Why not just burn hydrogen in an internal combustion engine? BMW does that.

[Consort]

Those scientists might own a lot of oil stocks or are employed by oil companies. Maybe.

[LOC1]

Yes, hydrogen molecules are much smaller than oxygen molecules.

Hydrogen is routinely produced in pertolem refineries and consumed in many refinery processes. It is difficult to contain, which really just means that it costs more money to contain it.

The real problem with hydrogen fuel cell technology is what happens when the hydrogen is generated. Most hydrogen generation process, like steam methane reforming, also generate a carbon rich byproduct, carbon monoxide, carbon dioxide, etc. Other process which use electric power to disassociate water to form hydrogen and oxygen require the power to be generated somewhere. That power generation generally generates carbon dioxide by burning a hydrocarbon. So the problem then becomes, what does one do with the carbon dioxide? There are thoughts about injecting it into salt caverns, or into depleted oil production zones. But there are problems and costs with the various proposals for carbon dioxide containment, which is what really limits the development of hydrogen technlogy.

[Cooter]

These atmospheric scientists seem to be at odds with the fuel cell program at Los Alamos. The quest for funding trumps all, I guess.

[buwaya]

H2 molecules are small, volatile, and hard to contain.

Much harder than O2.

You need better seals, seals that work at much lower temps than O2, pressures are higher and you need lower temps in general.

I have always thought that H2 as such was too much of a problem to distribute cheaply.

There are alternatives to feeding fuel cells - there's the Sodium Borohydride system for instance (Millenium Cell Inc.). This avoids transporting volatile gases.

There are other options too.

[buwaya]

The most environementally clean system is to set up additional nuclear power stations to do the seawater-cracking.

Power from fossil fuels does not avoid either the supply problems or the environmental problems of internal combustion engines.

[RightWhale]

I can't find any actual data of gas molecule sizes on this useless Internet. There are apparently several methods to store hydrogen, liquified hydrogen [cryogenic], metal hydride, glass microspheres, carbon absorption, probably more. One problem is that hydrogen is low density, which means the tank would have to be large if the hydrogen is stored as a liquid compared to gasoline to get the same energy. Hydrogen permeability is visualized mechanically as relatively small molecules even though we know the size of the hydrogen atom is one of the largest. Helium is a small molecule, really just the atom and a small atom at that, so a party balloon won't last long.

[RightWhale]

Right, a metal hydride tank works well. They say it takes half the energy available in the hydrogen just to liberate the hydrogen from its metal hydride.

[oncebitten]

Here is my idea for disposing of nuclear waste and making use of nuclear power more acceptable. Uranium makes a great projectile, right? We build a massive rail gun somewhere in the desert package the spent uranium in a case of some sort and fire it out of earth orbit into the sun. Is there any reason this will not work?

[resistance]

Oh, sure. Now we are going to contaminate the surface of our sun!

Yours truly,
Shiela Jackson Lee

[Axenolith]

Its not 1st on the PTE fer nothin'...

[buwaya]

With gaseous/liquid H2, you will need energy for refrigeration, costs for depreciation of the very expensive facilities and transport system, maintenance of same, etc.

This needs to come out in the cost analysis, but just because the overall energy efficiency of something like the borohydride system is lower does not mean it is uncompetitive.

[buwaya]

No need to bother.

It is fine to reprocess it in breeder reactors, and ultimately bury what is left in Nevada.

[RoughDobermann]

Scientists Question Hydrogen Fuel Cells

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