Purdue finds a better way to bust up water

Some very good news from Purdue University now requires that I give hydrogen-powered engines equal billing with ultrabatteries and ultracapacitors whenever I venture a guess as to which new technology might be the first to get us to oil independence day.   

Recent years' media hype about hydrogen fuel cell vehicles has typically focused on the sexy, silent-and-fast electric vehicle that emits only water from its tailpipe—while downplaying or even omitting the important question, But where will all that hydrogen come from?  Our gasoline production and distribution system took a hundred years and multi billions of dollars to build; how long and how much would it take to build one of those for hydrogen gas (which is far more uncooperative to make and move than gasoline is)? 

Too long and too much, that's what.  If sufficient quantities of hydrogen could not be produced very close to (or onboard) the car itself, the hydrogen-powered vehicle would turn out to be the 21st century version of those flying cars Tom Swift promised us fifty years ago, for which I'm still waiting. 

But the good news from Purdue changes the prospects dramatically: we just might be able to make an end run around the show-stopping need for massive hydrogen production and distribution infrastructure.  It's a way to split water into hydrogen and oxygen using an alloy of aluminum and gallium.  Electrolysis without (much) electricity.  Hydrogen on demand.  Goodbye gasoline.  [Go read the whole article here.]

In short, there just might be a powerful answer to the important question, But where will all that hydrogen come from?  The answer could be: My new car will manufacture it—as long as I remember to fill its tank up with water every so often. 

Obviously, there's a lot more for the scientists, engineers, entrepreneurs, and business managers to understand before we observers can safely turn this from a hope to a probability.  But I'm going to put hydrogen-powered vehicles back on my radar, up there with ultrabatteries and ultracapacitors.  Somebody could be getting very rich very soon from a breakthrough in one of those areas.  I hope so anyway... and I'm ready to contribute my fair share as soon as they've got something.   

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End note:
The QandO blog spotted the Purdue story yesterday; because that's my alma mater, I had to investigate further.  This, by the way, is the kind of university-spawned idea Paul Romer talks about in his interview with Russ Roberts; if you haven't listened to it yet, you're missing a treat. 

Comments

[Bob]

Sure beats the heck out of filling up the tank with food. Any bauxite in Iowa?

[James Dhimmi]

We may need a gallium-aluminum alloy infrastructure for this to work. It is not a catalytic reaction, because the aluminum gets oxidized and used up, so you would have to refuel your car with water, and replace the heavy converter block with a fresh block of aluminum-gallium alloy.

[mark]

I have worked in the power industry for 25 years. One of the first things I learned at Nuke power school in the Navy is "you can't get something for nothing". More technically - energy in equals energy out. My guess is recylcing all that alumina WILL require an energy input equal to the energy output minus losses. So it still goes back to generating ALL that energy required by the transportation system. It sounds like the efficiency of the system will make it cost competative, but that does not change the fact that the energy will still have to be generated somehow.
And by the way, if the car is using a fuel cell, you will not have to fill up with water. A fuel cell generates water so the water could just be recylced back to the input (some may have to be added to account for losses).

[Fat Man]

The process cited above essentially burns aluminum. Aluminum is extremely energy intensive to make.

Gutowski, T. “Design and Manufacturing for the Environment," chapter in the Handbook of Mechanical Engineering, Springer-Verlag*:

"For example, the production of 1 kg of aluminum requires on the order of 12 kg of input materials and 290 MJ of energy. The energy for this production plus other processing effects, in turn, leads to about 15 kg of CO2 equivalent for every kg of aluminum produced."

The press release cited above says:

"... recycle ... alumina back to aluminum at 20 cents per pound. Using aluminum, it would cost $70 at wholesale prices to take a 350-mile trip with a mid-size car equipped with a standard internal combustion engine. ... That compares with $66 for gasoline at $3.30 per gallon. If we used a 50 percent efficient fuel cell, taking the same trip using aluminum would cost $28."

The $70 of aluminum at $0.20/lbs is 350 lbs (157.8 kg). At 290 MJ/kg, it would require approximately 46,000 MJ of energy to refine. That is the same amount of energy as is contained in 1323 l (349 gal.) of gasoline, which would take my Accord on 20 such trips.

The problem with the previous quote is that aluminum is running around $2500/metric tonne (2205 lbs) on the London market, or more than $1/lbs, 5 times the $70/trip quoted.

The aluminum process for obtaining hydrogen is the electrochemical equivalent of roasting a pig by burning down a house. It is extraordinarily wasteful in economic and energetic terms.

* web.mit.edu/ebm/Gutowski%20Mech%20Eng%20Handbook%20Ch%20Dec%206%2020041.pdf

[mark]

Fat Man,
I think you are comparing apples and oranges. The energy statistic you give is for the production of aluminum that is probable from bauxite. The article gives a price to recycle alumina back to aluminum. Two different processes.
You do bring up a very good point. If the cost is 20 cents per pound and that results in 350 miles costing $70, then it must require 350 pounds to drive 350 miles. Imagine changing out 350 pounds of spent alumina for 350 pound of fresh aluminum every 350 miles. Not to mention trucking all that weight to and from the recycling stations (unless the recycling is done on location which will mean bringing the energy source for recycling to the location. Assuming it is electricity will require a dramatic improvement in the electric grid).
Don't mean to rain on the parade, but I think there is a lot more involved here than putting a block of aluminum in the car and telling the Arabs to kiss my gas.

[JD]

Sadly I see this as a non starter for transportation. Why generate hydrogen to "burn" in an ICE engine or even a PEM fuel cell (consider how pricey those are). If they have the tech to prevent the oxidation layer build up then go straight to an aluminum-air battery and an all electric vehicle. Why use electric potential to generate hydrogen that would be utilized with a 50% efficiency at best.

http://en.wikipedia.org/wiki/Aluminium_battery

Aluminum-air batteries have about four times the energy density of lead-acid. Good but not great. Some of the newer rechargeable lithiums reach that level.

My own opinion is that lithium battery equipped electric vehicles (let's not forget EESTOR if it's not a hoax) coupled with a highly efficient SOFC (multi-fuel potential, no platinum use and far far cheaper to build) would do the trick. SOFC's have suffered from long start up times, but if you have an appreciable battery powered range you simply let the SOFC do it's startup sequence while you drive. Research is ongoing and is steadily improving this facet. Such a fuel cell is ly much more energy efficient than the hydrogen fueled PEM (potential of near 70% ?). It would allow very extended trips or recharging of the lithium batteries when electrical service was unavailable.

[Fat Man]

"Imagine changing out 350 pounds of spent alumina for 350 pound of fresh aluminum every 350 miles. "Not to mention trucking all that weight to and from the recycling stations"

Mark: First, because the aluminum is being oxidized, the resulting alumina will be almost twice (~1.89) as heavy.

Second, the separation of alumina from bauxite (which is done by dissolving it in NaOH) is far less energy intensive than the high temperature electrolysis used to refine any alumina.

Third, the distribution of the aluminum gallium mixture, gathering the spent fuel, and reprocessing would consume a great deal of energy and other resources.

Fourth: how are you going to re-load your car? 350 lbs is a lot. Spent fuel would be even heavier. So much for self service.

Speaking of mixing apples and oranges, the Purdue press release I quoted compares the cost of reprocessing alumina with the retail cost of gasoline.

[embutler]

you missed the point of the new technology... you have to replace the compound...makes adding water trivial..