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Hydrogen Car Update

Engineer Poet provides a withering analysis of the potential viability of the car that produces its own fuel about which we recently wrote. It looks as though the efficiency just isn't there.

Good to know. However, I must take issue with EP's conclusion:

Forget Hydrogen!

Surely that's a little extreme? After all, it's the most abundant element in the universe. It's got to be good for something.

UPDATE FROM STEPHEN:

EP is right that energy is lost using hydrogen in a hydrogen fuel cell to produce electricity.

But this Engineuity concept car would use the hydrogen extracted from water in an internal combustion engine - exploding it like gasoline or diesel under pressure.

Also, there doesn't appear to be significant loss of energy from heat because the heat is recycled to aid the electrolysis - am I right about this heat recycling? Someone with a engineering background needs to study that schematic on this point.

Anyway, EP may be right about hydrogen fuel cells, but this is a different idea.

UPDATE II:

The original IsraCast article now has an audio interview of project leader Professor Amnon Yogev.

According to the interview, reclaiming heat energy is a very important part of this concept. According to Yogev:

If you don't find a way to use the heat...actually you reject half of the energy.

Comments

Aloha,

Just returning to the "Speculist" site from
"Betterhumans" and wanting to suggest a link to your site and blog posts. In the meantime, in an attempt to recall my old sign in name and password we tried out the radio you offer. One show, discussion of somebody having their 4th child -- "paternity leave" etc. brings us to these thoughts to share:

Now, this is a very sensitive subject and one that's not appreciated by the so called "moral majority" or the right wingers.

I'd just like to interject that perhaps we will never have a better world so long as people won't practice personal populaion control. (well, maybe if we get off the planet first and into space to begin to populate (and overpopulate yet another planetary body, then we may give unbidled liense to all the human breeders out there.).

No, we won't congradulate anyone in having a child -- especially now in these times and on this struggling planet.

Yes, this is a "hard pill to swallow". But nobody is perfect, even us queers out here who keep our weenies out of places that might make babies.

Bye-bye now, and thank you for providing your great site and all that. We appreciate all the great stuff you do. Really!

Live long, joyously prosper,
"Arun" the cynic ("vog")

Vog,

Thanks for reading and for the kind words about the site. Your comments are off-topic in this thread, however. In the future, please try to leave comments in the thread you are responding to.

You are a real blast from the past, my friend. I can't even remember the last time I heard the term "moral majority." They were big...when? Early 80's? (Maybe it's time to update those magazine subscriptions.)

Unfortunately, it appears that your views on population are of a similar vintage. Check the numbers...population figures are going down in parts of the developed world. And where they aren't going down, population is leveling off or the rate of growth is slowing. We don't need government programs or even self-righteous "Save the Planet" types to make this happen. It appears to be a natural result of economic growth.

Granted, the planet isn't perfect. Nor was it perfect a few years ago when you were born. If only your parents had been more self-disciplined and concerned about the welfare of earth, eh? A little personal population control on their part and you wouldn't even exist.

Wait, don't tell me. That's different, right? Sure it's different. Of course it is.

Anyhow, I would suggest that the real political struggle isn't between the left and the right any more -- it's between what Virginia Postrel describes as the Dynamists and the Stasists. Or as we like to say around here, between the Speculists and the Buzzkills*.

Not that we have anything against cynics; they keep the conversation lively. Plus we love watching them eat their words when the future turns out much better than they anticipated.

Aloha,

Phil

*You know, like people who refuse to congratulate new parents on the birth a child.

Burning the hydrogen in an IC engine doesn't make much sense either. IC engines are typically less efficient than fuel cells, and this fuel is already very expensive.

The whole idea would make more sense if the metal were used directly in a metal-air battery. This would avoid the need for a precious metal catalyst for a hydrogen electrode. Hydrogen does have serious problems in vehicles; probably its best use is to synthesize more convenient liquid fuels, such as methanol or Fischer-Tropsch diesel.

Paul:

I was also skeptical when I first read about this car. But after hearing the interview I was left thinking that either this is for real or its an unbelievably elaborate hoax.

According to the audio interview I pointed to, the project has completed its proof-of-concept phase. Now, apparently, they just need money to develop the technology.

Forget Hydrogen!

Surely that's a little extreme? After all, it's the most abundant element in the universe.

And all of it (on earth) is bound up in compounds like water. It will always take more energy to separate it then you will get back when you use the hydrogen is fuel. All processes are less then 100% efficient. IOW, hydrogen is not a fuel, it is an energy storage medium not unlike a battery.

EP’s analysis is optimistic, he doesn’t include the energy required to produce the aluminum or magnesium. The production of aluminum is quite energy intensive:

The production of aluminum begins with the mining and beneficiation of bauxite. At the mine (usually of the surface type), bauxite ore is removed to a crusher. The crushed ore is then screened and stockpiled, ready for delivery to an alumina plant. In some cases, ore is upgraded by beneficiation (washing, size classification, and separation of liquids and solids) to remove unwanted materials such as clay and silica. At the alumina plant, the bauxite ore is further crushed or ground to the correct particle size for efficient extraction of the alumina through digestion by hot sodium hydroxide liquor. After removal of “red mud” (the insoluble part of the bauxite) and fine solids from the process liquor, aluminum trihydrate crystals are precipitated and calcined in rotary kilns or fluidized bed calciners to produce alumina (Al2O3). Some alumina processes include a liquor purification step.
Primary aluminum is produced by the electrolytic reduction of the alumina. The alumina is dissolved in a molten bath of fluoride compounds (the electrolyte), and an electric current is passed through the bath, causing the alumina to dissociate to form liquid aluminum and oxygen. The oxygen reacts with carbon in the electrode to produce carbon dioxide and carbon monoxide. Molten aluminum collects in the bottom of the individual cells or pots and is removed under vacuum into tapping crucibles.

It will take more energy to convert the aluminum oxide into aluminum then you will get going from aluminum to aluminum oxide. The bottom line is the whole process results in a net loss of energy.
A Hoax.

This engine is not a hoax but it is also not a miracle by any means. The hydrogen is created through a process of endothermic reaction with the aluminum and combustion exhaust(steam). This is accomplished by running a weak electric current through the aluminum which causes the aluminum oxide to fall off during the reaction. Basically the real fuel is the extra electron in the aluminium which gets lent to the hydrogen in the h2o. This allows the hydrogen to be released and leaves a by-product of aluminum oxide. In order to recover the aluminum one simply elcroliyzes the aluminum oxide. So in reality the aluminum becomes a means of storing energy. You do not need to mine new aluminum. The problem with this system is that the hydrogen must be used in an ICE in order be able to recycle that heat into the chemical reaction. This solves the problem of petroleum combustion pollution but hydrogen is much more effective in a fuel cell because electric motors are far more efficient than heat engines. Its a good idea but probably unpractical for a number of reasons in the final analysis.

Greg:

"All processes are less then 100% efficient."

True, otherwise we'd be running the country off this nifty perpetual motion machine I've got stashed in my attic. :-)

But saying that it must be less than 100% efficient doesn't prove that this process is more than 100% inefficient - thereby costing us more energy to use it than we get out of it.

In order to be a useful technology, this process probably needs to be north of 20% efficient.

Micah just wrote a thoughtful post on the hydrogen economy over at Event Horizon.

In the post he states that hydrogen is not a fuel, but is a source of stored energy. He would define fuel as something readily attainable without chemical processes to free it up from other molecules.

I've heard this before, but in this case it strikes me as a distinction without a difference.

If you don't want to call hydrogen a fuel, but will concede that hydrogen is a form of stored energy, then we can move on to the next question:

Can this UNfuel be useful to us in any practical way? This is another way of asking whether the energy we can get out of burning hydrogen or using it in a fuel cell, etc., is worth the energy it takes to free it from other molecules - probably H2O.

That's what makes this potential Israeli development so exciting. These scientists are claiming that the answer is an unequivical "yes - hydrogen is worth the trouble."

So we believe them, or we don't, or we wait and see.

IF these scientists really have completed the proof of concept phase and are now ready to scale this up for development, then this is a very big deal.

The primary inputs to the system is aluminum oxide plus energy to produce aluminum. Using the most efficient process it takes 14kWh to produce 1kg of aluminum from aluminum oxide. The energy input to produce one mole of aluminum is 325 kCal. To produce of one mole of hydrogen (70.6 kCal) requires an input of 217 kCal (to produce the aluminum), a conversion efficiency of 32.6%. So tell me, why would you opt for a complex process that is at best 32.6% efficient when simple electrolysis of water can be had at 70% efficiency? The hoax is not that it won’t work mechanically, it is that it won’t work economically.

If you don't want to call hydrogen a fuel, but will concede that hydrogen is a form of stored energy, then we can move on to the next question:
Hydrogen is not a form of stored energy, it is a way of storing energy, much like a battery. Like a battery, to store energy in the form of hydrogen results in a net energy loss.

I see you did some research Stephen. That was the point I was trying to make but I was unsure of the math. Also you are right that the battery/fuel distinction is merely semantic. I was just using those labels as a convenience for distinguishing between a fuel that is ready made like oil, and a fuel that is merely a medium for storing energy like hydrogen. Any fuel-cell is really just a battery that can be 'refueled', i.e. recharged via a different method. I mean if water is a byproduct of a hydrogen fuel-cell and the hydrogen was achieved by electrolysis of water then the difference between an electric battery and a hydrogen fuel cell is mostly semantic as well.

correction: I meant to address Greg concerning the math.

I see Greg F. didn't read the source post fully, or he would have seen my caveat about losses in the metal reduction process.

I thank him for his figures (32.6% from electricity to hydrogen via aluminum?!) and note that a 25% conversion efficiency in an internal combustion engine (which is rather high) would produce a throughput of a mere 8.15%; wind power at 4.5¢/kWh put through such a pathway would cost 55¢/kWh at the crankshaft, considerably more than we're now paying for gasoline.

That won't fly.  To beat fossil fuels, the economics have to be even better to overcome the disadvantages in infrastructure and scale.

I'm not sure what the efficiency of aluminum-air batteries is, but if the throughput is as low as 25% the cost of 4.5¢/kWh wind power would rise to a whole 18¢ at the battery terminals.  What I've heard of rechargeable zinc-air cells says that their cycle efficiency is closer to 50%.

Ceteris paribus, you'd have to be an idiot to transfer energy at 8.15% efficiency when you could do it at 25% efficiency.  You'd have to be the heir to the kingdom of idiots to do it at 8.15% when you could do it at 50% efficiency!

(I can't help but compare to the subject line of the spam I just got, which I shall not repeat here out of deference to family values.  Suffice it to say that both are about equally credible.)

I've mentioned the exceptions to my rule before:  if hydrogen is the direct product of a process such as algal photosynthesis, it makes a great deal of sense.  If it has to be extracted from water using electricity or an even less direct method, it makes no sense at all.

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