What’s Wrong with Fuel Cells?
January 12th, 2007 by Stephen
When confronted with the issue of diminishing reserves of oil and our car dependent culture that consumes more and more of these reserves, I often here the retort:
Electric fuelcell operated vehicles, in my opinion, are the answer.
Wrong.
A fuel cell vehicle is powered by hydrogen gas, which is turned into water as a byproduct of the process. It is nice and clean on a local level, but think for a minute: where are the hydrogen mines?
We obtain hydrogen in a copule of ways. We can use hydrocarbon fuels and catalytic cracking - but then we are still using fossil fuels. The other method is through a form of electrolysis of water. This splits the hydrogen from the oxygen in the water, which can then be used in a fuel cell (the same process is used to create rocket fuel, where both hydrogen and oxygen are gathered).
But the law of conservation of energy says this: if you turn water into hydrogen and then back into water, then at maximum efficiency, the energy used to create the hydrogen is equal to the energy you gain from that hydrogen later.
Fuel cells are not 100% efficient, but even if they were, they would be nothing but batteries. They store the input of energy for later use.
Electrolysis requires electrical energy, but wher does that energy come from? Well some of it can come from renewable sources, some of it from nuclear power, but most of it comes from burning fossil fuels, and certainly if our requirement increases significantly then we will be forced to meet those requirements by burning more fossil fuels.
Okay, so we can burn coal and gas as well as oil, but we are still back where we started - using capital reserves of energy as if they were income.
Fuel cells are not the answer - they are merely an enabling technology.
I think you make excellent points here, Stephen– we’re simply moving where we expend the fuel to somewhere else. I’ve heard this same argument when it comes to corn based fuel (ethanol) where we end up expending fossil fuel to convert it to ethanol to burn it, and we end up wasting more energy than we are saving.
I guess the only part of this that would seem reasonable is IF we could figure out how to expend less energy over time to create the hydrogen batteries or ethanol, or the engines of the new cars could expect to maintain a better consistency in usage such that it made it more feasible overtime, otherwise we are only having a symbolic item, rather than a substantive one.
Yes indeed. However, there is some hope for hydrogen production. Imagine if you built a massive array of solar panels in the Sahara. You could then build a sea water pipeline into the Sahara to bring water there, and use the solar energy to produce hydrogen. The hydrogen could be pumped into dirigibles which would be flown to wherever it is needed.
In the U.S., the Mojave would be a suitable replacement for the Sahara.
Certain problems exist:
If you start collecting sea water, you have a hazard around the intake, and a filtration problem.
As you must pump to a point above sea level, you must use some energy to transport the water.
You would need a lot of dirigibles!
The risk of fire in the dirigibles is overstated by people remembering the Hindenberg disaster. The risk to the dirigible comes from the nature of the air frame rather than the gas it holds.
But this is one possible solution to the Hydrogen problem.
Unfortunately we are a long way from it, and even when we have it, it will not sustain our current levels of fossil fuel use I think (because of the hydrogen transportation problem).
Thanks for the comment.
I guess I never would have thought of the dirigibles– that is an interesting alternative.
Are you sure on your data about diminishing “fossil fuels”? I believe that I heard two different things that would confront that data.
As far as generating energy– it seems that it’s more acceptable to burn coal for electricity than for propulsion, so that would be one plus on the hydrogen/ethanol camps.
This is all interesting, mostly new to me.
I wanted to say I’m jealous of your header picture, Stephen! It’s beautiful. I might try this theme to see if it will accept more panoramic pics than the one I currently use. Do you have any tricks up your sleeve? :O)
The header pic came with the theme, so I can’t claim any credit for it, unfortunately.
Thanks for stopping by.
Stephen
I think the future of hydrogen production will come from many sources and not just dirty fossil fuels or the electrolysis of water. Hydrogen can be created in more ways than have been listed here.
For instance, there is direct solar-to-hydrogen, hydrogen from biogas (from landfills, industrial and farm waste), clean coal technology ala FutureGen with near-zero emissions and hydrogen from hydrogen-rich chemical compounds such as sodium borohydride.
The future lies in alternative ways to produce this alternative fuel.
Kevin, thanks for stopping by.
Hydrogen from waste products is another source I did not mention, but it is a relatively small source. An important renewable, but insufficient for the massive demand if all vehicles moved to hydrogen power without a reduction in vehicle use.
Clean coal and other clean chemical technologies are clearly better for the environment, but do not deal with the issue I raised: that they consume capital reserves of energy - which by their nature are limited. It is bad management to spend your capital as though it were revenue.
Direct solar to hydrogen is mentioned above. It is done with a form of electrolysis, with electricty being generated through photovoltaic cells.
As I pointed out in my comments, I do see future for fuel cells as an enabling technology through mass production of renewable hydrogen. However, I don’t believe current usage is sustainable, and the technology is a long way off.
Thanks for your comment.
Stephen
Min, I don’t think fossil fuels are renewable. In any case, any renewal of energy needs ultimately to come from the sun.
You are right that oil will not actually run out. At some point the energy cost of extraction of the oil will exceed the energy of the fule. At this point the remaining oil will largely be left in the ground (although there will be some extraction for other oil based products perhaps).
But the fossil fuel reserves are limited.