Posted on 06/19/2005 6:26:00 PM PDT by calcowgirl
Hydrogen can be supplied to a fuel cell directly or may be obtained from natural gas, methanol or petroleum using a fuel processor, which converts the hydrocarbons into hydrogen and carbon dioxide through a catalytic chemical reaction.
There are just a couple of problems with that process.
1. If producing hydrogen is going to produce carbon dioxide, a greenhouse gas, it would be much more efficient to just burn the hydrocarbon in the first place (and besides, there's no real value to burning hydrogen, since you won't be reducing the production of greenhouse gases, you'll just be producing them somewhere besides in your automobile).
2. Energy has to be supplied to break the hydrocarbon into hydrogen and carbon dioxide - where do you get that energy, and how much pollution is produced in supplying it?
Also, forgot to add, if we're getting the hydrogen by breaking down petroleum or natural gas, it doesn't reduce our dependence on fossil fuels.
"Water vapor is a more significant green house gas than CO2."
That's my concern as well. More water vapor>>more clouds>>global cooling>>more rain/flooding.
..Remember when TI first came out with themI BOUGHT a couple of those for use in engineering classes (it gets so tedious looking up sine, cosine and tan values et al in tables!); I still have the SR-50 (although the batts are gone) that got me through school - so we've not covered any new ground yet in our discussion.
I do hope that you look into the economics of some of the alternaive fuels, such that you gain a better appreciation for real costs (of production and farming of crops destined for fuel use) and market forces (WHAT the market will pay for a given commodity).
I still stand by my earlier statement as well: "I can't believe that anything is cheaper than raw feedstock that is pumped out of the ground ..."
I have some training in physics and some in engineering. I know something about people who like to employ themselves in those disciplines. Many of them, seems like, don't even have time for a life. So to speak.
The hybrid car is too small for my taste, but the picute of the vehicle I saw a few months back looked like an SUV that was modified to use fuel cells. One I read about actually used methane made with pig manure :^)....Now that's really thumbing the nose at the ME.
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lol
oops .. sorry.
Yeah, and if this were to actually become a reality some other group of Californian enviro-whacko fruitloops would come out of the granola box to protest that hydrogen kills... something... ANYTHING, because we can't solve the enviro-energy issue or they'll be out of a job blaming Bush!!
The other issue is efficiency, and I don't refer to mechanical efficiency but cost. Looking at efficiency from beginning to end it seems that hydrogen has to cost more than oil/gas to our transportation fleet. And it is so. But, somebody is looking ahead and seeing that oil/gasoline will not always be sufficiently available or cheap as it is now. That equation will give different results than it does now. Those who are complaining about the efficiency of a hydrogen economy will hopefully see the light--that mechanical efficiency is important, but not necessarily the determining factor.
IMO If they are going to be cost effective they will use methanol....On my computer that crashed there was a long list of all the bi-produces that were now considered waste that could be turned into methanol......We have one of the larger "dumps" in the midwest a few miles from here (Click on Hoosiermama) Would love to see 90% of it turned into energy....Probably not in my lifetime, but maybe my grandchildrens.
Jim, Does it count that I still have my slide rule?
"It can be produced from molecules called hydrocarbons by applying heat."
And the heat comes from WHERE..???
By burning fossil fuels to make steam of course...or splitting atoms.....
From the Ballard information page:
The core of the Ballard® fuel cell consists of a membrane electrode assembly (MEA), which is placed between two flow-field plates.
The MEA consists of two electrodes, the anode and the cathode, which are each coated on one side with a thin catalyst layer and separated by a proton exchange membrane (PEM). The flow-field plates direct hydrogen to the anode and oxygen (from air) to the cathode.
When hydrogen reaches the catalyst layer, it separates into protons (hydrogen ions) and electrons.
The free electrons, produced at the anode, are conducted in the form of a usable electric current through the external circuit. At the cathode, oxygen from the air, electrons from the external circuit and protons combine to form water and heat.
I understand that. The question is how you obtain the hydrogen.
Natural gas is the primary source of hydrogen now. Methanol might do, either directly or as converted to hydrogen. There are cars already that can run on alcohol or gasoline at the flip of a switch. That isn't hydrogen, but alcohol could run the fleet, and does, if I hear right, in Brazil.
I know Alan, and you are wrong.
It's simple...ethanol to run cars, nukes for everything else. We can do this now.
Hopefully our great-great-grandchildren. :)
Just found a book you may find interesting...It's not on cars but flight. WINGS OF THEIR DREAMS (Purdue In Flight) by John Norberg Published by Purdue University Press...
Love the dedication:
"To the Purdue people of yesterday and today who have dedicated their lives to flight and to the next generation of visionaries who will fashion tomorrow on the wings of their dreams...."
Now it's time for Hoo mama to do a little dreaming...Night
..ethanol to run cars, nukes for everything else. We can do this now.Some analyists point out that we don't have enough of something termed 'farmland' to produce the required ethanal; not to mention the current pipline infrastructure (national piping system) won't handle pure ethanol either ...
Thermodynamics of the Corn-Ethanol Biofuel Cycle
[the] conclusion is that corn ethanol is a net loss to the environment and in energy, and a net contributor of CO2.Corn ethanol research is funded because the farmers are a powerful lobby, not because it makes sense to grow corn for energy.Conclusions
- Excluding the restoration work of decontaminating aquifers, rivers, and the Gulf of Mexico, the minimum cumulative exergy consumption in restoring the environment polluted and depleted by the industrial corn-ethanol cycle is over 7 times higher than the maximum shaft work of a car engine burning the cycle's ethanol.
- This unfavorable ratio decreases to ~4, when an efficient internal combustion engine is used to burn the ethanol, and to 2.4 when an imaginary hydrogen fuel cell is used.
- The industrial corn cycle is not renewable, and is unsustainable by a wide margin (at least 2.4 -- 7.1 times).
- No process changes can make this cycle more viable.
- The annual corn-ethanol biofuel production is a human assault on geologic processes and the geologic time scale, and it can never work.
- The limiting factors, nutrient-rich humus and water that carries the dissolved nutrients to plant roots are augmented by chemicals obtained in the linear, irreversible fossil fuel-based processes.
- Over the last fifty years, corn yield has grown five-fold, mostly because of the steep increases in fertilization rate of corn fields.
- Sunlight is not a limiting factor, and could be used to great benefit if we were in less of a hurry
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