Hydrogen Breakthrough

[Haminal10]

Link

The technology produces hydrogen by adding water to an alloy of aluminum and gallium. When water is added to the alloy, the aluminum splits water by attracting oxygen, liberating hydrogen in the process. The Purdue researchers are developing a method to create particles of the alloy that could be placed in a tank to react with water and produce hydrogen on demand.

The gallium is a critical component because it hinders the formation of an aluminum oxide skin normally created on aluminum's surface after bonding with oxygen, a process called oxidation. This skin usually acts as a barrier and prevents oxygen from reacting with aluminum. Reducing the skin's protective properties allows the reaction to continue until all of the aluminum is used to generate hydrogen, said Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue who invented the process.

Since the technology was first announced in May, researchers have developed an improved form of the alloy that contains a higher concentration of aluminum.

Recent findings are detailed in the first research paper about the work, which will be presented on Sept. 7 during the 2nd Energy Nanotechnology International Conference in Santa Clara, Calif. The paper was written by Woodall, Charles Allen and Jeffrey Ziebarth, both doctoral students in Purdue's School of Electrical and Computer Engineering.

Because the technology could be used to generate hydrogen on demand, the method makes it unnecessary to store or transport hydrogen - two major obstacles in creating a hydrogen economy, Woodall said.

The gallium component is inert, which means it can be recovered and reused.

"This is especially important because of the currently much higher cost of gallium compared with aluminum," Woodall said. "Because gallium can be recovered, this makes the process economically viable and more attractive for large-scale use. Also, since the gallium can be of low purity, the cost of impure gallium is ultimately expected to be many times lower than the high-purity gallium used in the electronics industry."

As the alloy reacts with water, the aluminum turns into aluminum oxide, also called alumina, which can be recycled back into aluminum. The recycled aluminum would be less expensive than mining the metal, making the technology more competitive with other forms of energy production, Woodall said.

In recent research, the engineers rapidly cooled the molten alloy to make particles that were 28 percent aluminum by weight and 72 percent gallium by weight. The result was a "metastable solid alloy" that also readily reacted with water to form hydrogen, alumina and heat, Woodall said.

Following up on that work, the researchers discovered that slowly cooling the molten alloy produced particles that contain 80 percent aluminum and 20 percent gallium.

"Particles made with this 80-20 alloy have good stability in dry air and react rapidly with water to form hydrogen," Woodall said. "This alloy is under intense investigation, and, in our opinion, it can be developed into a commercially viable material for splitting water."

The technology has numerous potential applications. Because the method makes it possible to use hydrogen instead of gasoline to run internal combustion engines, it could be used for cars and trucks. Combusting hydrogen in an engine or using hydrogen to drive a fuel cell produces only water as waste.

"It's a simple matter to convert ordinary internal combustion engines to run on hydrogen. All you have to do is replace the gasoline fuel injector with a hydrogen injector," Woodall said.

The U.S. Department of Energy has set a goal of developing alternative fuels that possess a "hydrogen mass density" of 6 percent by the year 2010 and 9 percent by 2015. The percent mass density of hydrogen is the mass of hydrogen contained in the fuel divided by the total mass of the fuel multiplied by 100. Assuming 50 percent of the water produced as waste is recovered and cycled back into the reaction, the new 80-20 alloy has a hydrogen mass density greater than 6 percent, which meets the DOE's 2010 goal.

Aluminum is refined from the raw mineral bauxite, which also contains gallium. Producing aluminum from bauxite results in waste gallium.

"This technology is feasible for commercial use," Woodall said. "The waste alumina can be recycled back into aluminum, and low-cost gallium is available as a waste product from companies that produce aluminum from the raw mineral bauxite. Enough aluminum exists in the United States to produce 100 trillion kilowatt hours of energy. That's enough energy to meet all the U.S. electric needs for 35 years. If impure gallium can be made for less than $10 a pound and used in an onboard system, there are enough known gallium reserves to run 1 billion cars."

The researchers note in the paper that for the technology to be used to operate cars and trucks, a large-scale recycling program would be required to turn the alumina back into aluminum and to recover the gallium.

"In the meantime, there are other promising potential markets, including lawn mowers and personal motor vehicles such as golf carts and wheelchairs," Woodall said. "The golf cart of the future, three or four years from now, will have an aluminum-gallium alloy. You will add water to generate hydrogen either for an internal combustion engine or to operate a fuel cell that recharges a battery. The battery will then power an electric motor to drive the golf cart."

Another application that is rapidly being developed is for emergency portable generators that will use hydrogen to run a small internal combustion engine. The generators are likely to be on the market within a year, Woodall said.

The technology also could make it possible to introduce a non-polluting way to idle diesel trucks. Truck drivers idle their engines to keep power flowing to appliances and the heating and air conditioning systems while they are making deliveries or parked, but such idling causes air pollution, which has prompted several states to restrict the practice.

The new hydrogen technology could solve the truck-idling dilemma.

"What we are proposing is that the truck would run on either hydrogen or diesel fuel," Woodall said. "While you are on the road you are using the diesel, but while the truck is idling, it's running on hydrogen."

The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.

"You could replace nuclear submarines with this technology," he said.

Other types of boats, including pleasure craft, also could be equipped with such a technology.

"One reason maritime applications are especially appealing is that you don't have to haul water," Woodall said.

The Purdue researchers had thought that making the process competitive with conventional energy sources would require that the alumina be recycled back into aluminum using a dedicated infrastructure, such as a nuclear power plant or wind generators. However, the researchers now know that recycling the alumina would cost far less than they originally estimated, using standard processing already available.

"Since standard industrial technology could be used to recycle our nearly pure alumina back to aluminum at 20 cents per pound, this technology would be competitive with gasoline," Woodall said. "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 Purdue Research Foundation holds title to the primary patent, which has been filed with the U.S. Patent and Trademark Office and is pending. An Indiana startup company, AlGalCo LLC., has received a license for the exclusive right to commercialize the process.

In 1967, while working as a researcher at IBM, Woodall discovered that liquid alloys of aluminum and gallium spontaneously produce hydrogen if mixed with water. The research, which focused on developing new semiconductors for computers and electronics, led to advances in optical-fiber communications and light-emitting diodes, making them practical for everything from DVD players to television remote controls and new types of lighting displays. That work also led to development of advanced transistors for cell phones and components in solar cells powering space modules like those used on the Mars rover, earning Woodall the 2001 National Medal of Technology from President George W. Bush.

Also while at IBM, Woodall and research engineer Jerome Cuomo were issued a U.S. patent in 1982 for a "solid state, renewable energy supply." The patent described their discovery that when aluminum is dissolved in liquid gallium just above room temperature, the liquid alloy readily reacts with water to form hydrogen, alumina and heat.

Future research will include work to further perfect the solid alloy and develop systems for the controlled delivery of hydrogen.

The 2nd Energy Nanotechnology International Conference is sponsored by the American Society of Mechanical Engineers and ASME Nanotechnology Institute.

Note: This story has been adapted from a news release issued by Purdue University.

Sounds really interesting.

[Uraniun235]

The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.

"You could replace nuclear submarines with this technology," he said.

I'm pretty skeptical of that, given the enormous difference between chemical and nuclear reactions.

[Fingolfin_Noldor]

Sounds similar to the electrolysis method of coating aluminium.

[Sea Skimmer]

They’ve been working on this technology for some time; it’s not an enormous advantage over pressurized tanks in terms of fuel load in a given sized vehicle, but it is a good deal more practical and safer. Hydrogen technology isn’t really going to take off until this works well enough to be put into mass production. That is still some time off.

[PeZook]

They’ve been working on this technology for some time; it’s not an enormous advantage over pressurized tanks in terms of fuel load in a given sized vehicle, but it is a good deal more practical and safer. Hydrogen technology isn’t really going to take off until this works well enough to be put into mass production. That is still some time off.

Furthermore, it's awesome because we won't have to build an entirely new distribution infrastructure. You can use existing gas stations or even home faucets to refuel.

[Singular Intellect]

They’ve been working on this technology for some time; it’s not an enormous advantage over pressurized tanks in terms of fuel load in a given sized vehicle, but it is a good deal more practical and safer. Hydrogen technology isn’t really going to take off until this works well enough to be put into mass production. That is still some time off.

Furthermore, it's awesome because we won't have to build an entirely new distribution infrastructure. You can use existing gas stations or even home faucets to refuel.

That was my immediate reaction. If we could throw enough resources and effort into this system and it works well enough, could be a great way to replace our oil dependency.

Can't say I'm really counting on it though...

[Zixinus]

Quote:
The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.

"You could replace nuclear submarines with this technology," he said.

I'm pretty skeptical of that, given the enormous difference between chemical and nuclear reactions.

And the enormous energy difference. This thing could competite as a backup generator, but not as a primary. If I read right, this method basically uses aluminium corrosion controlled by gallium. Essentally, a highly improved version of generating hydrogen. However, the aluminium is going to eventually corrode to the point that it won't generate power. A nuclear battery's lifetime is measured in the half-lifes and the tolerance of the thermocouples. I'm willing to bet that the former goes faster.

[Molyneux]

Quote:
The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.

"You could replace nuclear submarines with this technology," he said.

I'm pretty skeptical of that, given the enormous difference between chemical and nuclear reactions.

And the enormous energy difference. This thing could competite as a backup generator, but not as a primary. If I read right, this method basically uses aluminium corrosion controlled by gallium. Essentally, a highly improved version of generating hydrogen. However, the aluminium is going to eventually corrode to the point that it won't generate power. A nuclear battery's lifetime is measured in the half-lifes and the tolerance of the thermocouples. I'm willing to bet that the former goes faster.

(I know that both forms are technically correct, but we really need to settle between aluminum and aluminium. Perhaps a Brit chemist and an American chemist could flip a coin?)

What I would like to know is exactly how much aluminum and gallium are required to acquire a significant amount of hydrogen in a reasonable time frame.

[Knife]

Didn't I just post this last week?

Anyway, I don't see it replacing gasoline anytime soon. Just mining the aluminium not to mention the gallium will require quite a bit of energy. Both will have to be seriously ramped up considerably.

However, as a large scale way to produce hydrogen without buring coal to make it, it looks good.

[Molyneux]

Didn't I just post this last week?

Anyway, I don't see it replacing gasoline anytime soon. Just mining the aluminium not to mention the gallium will require quite a bit of energy. Both will have to be seriously ramped up considerably.

However, as a large scale way to produce hydrogen without buring coal to make it, it looks good.

The article does mention that the aluminum and gallium can be recycled at a much lower cost than the costs of mining.

[Sikon]

"Since standard industrial technology could be used to recycle our nearly pure alumina back to aluminum at 20 cents per pound, this technology would be competitive with gasoline," Woodall said. "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.

Such suggests around 350 pounds of aluminum per vehicle (350lb * $0.20/lb = $70). From their earlier discussion of an 80-20 aluminum-gallium alloy, the total per vehicle may be around 430 pounds of hydrogen-storing metal: ~ 350 lb aluminum and ~ 90 lb gallium. At the hydrogen mass density of 6% mentioned, such corresponds to storing around 26 pounds of hydrogen, which has several times higher energy content than an equal weight of gasoline.

Since that would add up to several hundred pounds extra weight to a vehicle which may have a base weight of several thousand pounds, it would moderately affect fuel efficiency, but that's not large enough of an effect to be of concern in these approximate calculations.

For example, for a couple hundred million vehicles, that would be 35 million tons of new aluminum needing to be mined and ~ 8.8 million tons of impure gallium.

Thus, although this is not actually expected to occur, if one pretended there was such a switch to this fuel system over a period of 3 decades, an order of magnitude estimate of the amount of new aluminum being mined and added to the aluminum<-->alumina recycling system would be ~ 1.2 million tons on average annually during the 30-year conversion.

At current prices, there would be ~ $2.6 billion new mined aluminum expense during each year of conversion. For example, at around the personnel requirements that exist for current aluminum production per million tons produced annually, that amount of extra aluminum mined would require on the order of 20,000 new workers. (That's not 20,000 new workers per year but rather just like adding 20,000 new employees who worked for thirty years each). Using their figure of <= $10/lb for impure gallium gives a cost estimate for the new gallium of <= ~ $0.6 billion per year during conversion.

Of course, there's also the expense of constantly using and recycling the aluminum in this system, which would involve more continuing expense and more workers than the initial aluminum production from mines. Indeed, that would be up to hundreds of billions of dollars a year, vastly more than the original aluminum mining expense, as the aluminum again and again became alumina converted back into non-oxidized form. However, the earlier quote from the article implies how it is relatively comparable in magnitude to the expense of $3.30/gallon gasoline, e.g. ~ $70 energy expense for a 350 mile trip with either this system or $3.30/gallon gasoline.

As a result, the actual net cost can be far less than hundreds of billions a year. There's some more expense, like modifying engines, though that's technically affordable if spread out over a number of years or decades.

However, although they gave an illustration with gasoline at $3.30 per gallon, when one considers the extra trouble involved in dumping used alumina and getting new metal at gas stations, their system is not fully competitive with gasoline at that close to current prices. Customers would view it as a nuisance, and gas stations would have to charge extra to have someone replacing the metal in each vehicle being refueled (or else spend money installing equipment to do that).

It is workable, though, if the competitives weren't so cheap. If a tank of regular gasoline someday cost a few hundred dollars instead of the $70 or so that it does currently, then customers might become willing to accept the extra trouble, due to being motivated by saving large amounts of money. But that motivation doesn't exist today.

Thus, although the system is technically a workable solution, it will have little to no success in the general automobile marketplace in the immediately foreseeable future, due to competition from alternatives such as currently $3/gallon gasoline.

They might find some smaller market niches, though. For example, there could be specialty applications where some customers might much prefer storing a container of metal that reacts with water rather than storing flammable gasoline. Such would make sense with the following quote:

Another application that is rapidly being developed is for emergency portable generators that will use hydrogen to run a small internal combustion engine. The generators are likely to be on the market within a year, Woodall said.

If they had just said commercialization was a vague time like 10 or 20 years away, that might not occur, but them expecting sales of such to occur within a year suggests that they have a serious development plan for those generators.

[Sikon]

The article does mention that the aluminum and gallium can be recycled at a much lower cost than the costs of mining.

Yes. And I just realized some clarification of my previous post may help the casual reader.

Aluminum can be recycled from alumina in this system at less than the cost of mining it per use. However, while it is only mined once, it may be repeatedly recycled many times per year, still more times per decade. As a result, the total cost for recycling it many times amounts to much more than the cost of first mining it once. That is addressed in the article, though, in their cost estimate of recycling aluminum used in a 350-mile trip (350 pounds of it) at $0.20/lb, where it is more expensive than current < $3/gallon gasoline prices but not vastly so.

[Sikon]

EDIT:

To slightly adjust wording in my first post, this doesn't literally store hydrogen, not like a metal hydride. But by producing hydrogen on demand when reacted with water, it is equivalent to such.

[Sikon]

One last edit:

Using their figure of <= $10/lb for impure gallium gives a cost estimate for the new gallium of <= ~ $0.6 billion per year during conversion.

... should be instead:

Using their figure of <= $10/lb for impure gallium gives a cost estimate for the new gallium of <= ~ $6 billion per year during conversion.

[Knife]

An easier system would be to have the fueling stations recieve the aluminium and gallium and convert it on site to Hydrogen, then the cars would fuel up on the hydrogen. In effect the gas station becomes a small refinary/pumping station, rather than large tankers traveling around full of hydrogen.

[Sikon]

An easier system would be to have the fueling stations recieve the aluminium and gallium and convert it on site to Hydrogen, then the cars would fuel up on the hydrogen. In effect the gas station becomes a small refinary/pumping station, rather than large tankers traveling around full of hydrogen.

In that case, the hydrogen would have to be stored on the vehicles by some method like compressed tanks of hydrogen gas or metal hydrides, eliminating the point of this system.

From this and your past post, it looks like you are thinking of this as a general hydrogen generation method:

However, as a large scale way to produce hydrogen without buring coal to make it, it looks good.

But this is not advantageous for stationary, industrial generation of hydrogen over just electrolysis or steam reforming. For example, it's not more efficient to make aluminum from alumina, react the aluminum with water to produce hydrogen plus alumina, and process the alumina back into aluminum using electricity than to just electrolyze the water directly; it's actually less efficient in itself.

For example, using the common Hall-Heroult process technique, taking alumina (Al2O3), dissolving it in molten cryolite, electrolyzing the mixture, obtaining aluminum, then having 2Al + 3H2O --> Al2O3 + 3H2 is not done for stationary, industrial generation of hydrogen. It's possible, but not quite as simple and cheap as 2H2O --> 2H2 + O2 with electricity in electrolysis or producing hydrogen through steam reforming.

But the point of this is for hydrogen generation in a mobile vehicle, which doesn't have the outside electricity supply, which isn't connected to a stationary power line.

Bear in mind, there's no net energy gain from this system, as rather its function is more analogous to rechargeable batteries in an electric vehicle. If all the electricity generation was coal powered, you'd use as much or rather more coal than before, using much electricity to convert alumina back to aluminum. However, its benefit would be if the energy came from non-fossil-fuel power plants, e.g. nuclear power plants, being a method of making cars indirectly nuclear-powered rather than consuming gasoline.

The point of this is as an alternative to storing hydrogen on vehicles by other methods like compressed hydrogen tanks or metal hydrides. I'm not convinced it is actually superior to those methods or to other alternatives overall. But its goal is to avoid their disadvantages, and it would be a technically workable solution, whether or not it was the best solution.

[Knife]

I'm going from the presumption (as I recall from the guys website) that all this is predicated on the idea of lowering the enviromental factors in oil and coal, not necassarily the most efficient way to go from mining to fuel to power in your car.

Which is why I don't really think it'll replace gasoline. If you insist on making it power cars, then as a larger infrastructure to make hydrogen large scale without using coal fired plants to make the hydrogen seems a better route.

[Zixinus]

(I know that both forms are technically correct, but we really need to settle between aluminum and aluminium. Perhaps a Brit chemist and an American chemist could flip a coin?)

http://dictionary.reference.com/browse/aluminium

http://dictionary.reference.com/browse/aluminum

Both are correct. There is a large list of differences between British and American English. This is just one more entry.

Also, I guessed my spelling from the Hungarian spelling, which is "aluminium". We take allot of words from other languages. Sometimes too much.

They might find some smaller market niches, though. For example, there could be specialty applications where some customers might much prefer storing a container of metal that reacts with water rather than storing flammable gasoline.

Storing aluminium that corrodes without control and released boom-gas in the process is a that better alternative?

[Molyneux]

(I know that both forms are technically correct, but we really need to settle between aluminum and aluminium. Perhaps a Brit chemist and an American chemist could flip a coin?)

http://dictionary.reference.com/browse/aluminium

http://dictionary.reference.com/browse/aluminum

Both are correct. There is a large list of differences between British and American English. This is just one more entry.

Also, I guessed my spelling from the Hungarian spelling, which is "aluminium". We take allot of words from other languages. Sometimes too much.

No, I know that both versions are technically correct - but as far as I know, it's the only element on the periodic table known by more than one name. One way or another, a single name really should be settled upon.

[Sikon]

However, as a large scale way to produce hydrogen without buring coal to make it, it looks good.

[...]
An easier system would be to have the fueling stations recieve the aluminium and gallium and convert it on site to Hydrogen, then the cars would fuel up on the hydrogen. In effect the gas station becomes a small refinary/pumping station, rather than large tankers traveling around full of hydrogen.

[...]
If you insist on making it power cars, then as a larger infrastructure to make hydrogen large scale without using coal fired plants to make the hydrogen seems a better route.

Its purpose is not to make hydrogen on a large scale industrially, and, if one pretended it was illogically used for such, not zero but more coal power plants would be involved in producing hydrogen through it than in producing hydrogen more directly ... unless one first changes the primary source of electricity powering aluminum recycling plants, e.g. to nuclear power.

But I already explained that its suitability is only to provide a mobile, portable source of hydrogen. It is equivalent to a hydrogen storage method, in which a vehicle carries around metal and a tank of water instead of a bulky highly compressed tank of hydrogen gas.

The difference between this and a system aimed at producing hydrogen for general industrial production is like the difference between a battery producing electricity and a power plant producing electricity. It is like a battery, providing mobile power. Outside of portable usage, it would lack its practical purpose compared to the alternatives.

Indeed, as an analogy, if there is a new rechargeable battery system developed for electric cars, it is not an improvement to suggest having the batteries kept in gas stations instead of in the vehicles, to provide electricity to the gas stations (rather than the stationary gas stations running on power from the power lines). Such misses the whole point, of the batteries not being a net energy source but just suited to being a portable energy supply. If you don't put the aluminum-gallium alloy system in the vehicles, instead illogically using it for stationary industrial hydrogen production infrastructure, then you need some other method for the cars to have hydrogen onboard.

Storing aluminium that corrodes without control and released boom-gas in the process is a that better alternative?

Have a container of aluminum exposed to a spark by accident, and it doesn't explode. That's not always true for a tank of gasoline, in contrast.

To have this cause an explosion from hydrogen would require a series of circumstances: First, the aluminum alloy in storage would have to be in contact with water through some accident. Then, since ordinarily the hydrogen gas produced over a period of time would just disperse into the atmosphere rather than building up, such would have to occur in a confined volume. Otherwise, the extremely low molecular weight of hydrogen causes it to be buoyant, with the hydrogen generated rapidly diffusing to below its flammability range. The confined volume would have to be large enough for it to be a powerful explosion. Then, finally, an accident providing the ignition source must occur.

A twenty gallon tank of gasoline has an energy content of 2600 MJ. For perspective, that much energy in hydrogen requires 18 kg, which takes a minimum of ~ 200 cubic meters volume (like a dozen moderate-sized rooms) to confine at atmospheric pressure and typical temperature due to its extreme low density in gaseous form.

Compressed tanks of hydrogen gas are more dangerous than the preceding since the hydrogen is orders of magnitude more dense, under high pressure. This metal method does have advantages over such in some regards, both in compactness, and, to some degree, potentially even in safety.

In some ways, it is a little analogous to binary chemical warheads, where instead of having nerve gas itself stored, two less dangerous chemicals were stored separately apart from each other, which only upon combination became the nerve gas.

Whether or not this is overall superior to alternatives is a different question, but there are potential reasons why some customers might prefer storing a container of this metal for a portable generator over storing a container of gasoline. In some applications, it could have some safety advantages. Neither it nor other fuels are perfectly safe, but neither is gasoline.

[Ender]

The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.

"You could replace nuclear submarines with this technology," he said.

I'm pretty skeptical of that, given the enormous difference between chemical and nuclear reactions.

Yet diesel subs are still competitive today. The advantage of nuclear technology is its long term application, not its high power. The power demands are easily met by chemical technology, but the fact that they can keep meeting those demands indefinitely is a major edge. This could in theory negate it.

[aerius]

One thing I'm wondering about. We're taking doped aluminum and turning it into alumina to make hydrogen, then refining the alumina back into aluminum to start the process all over again. The refining process as I understand it involves electrolysis and a crapload of electricity.

What I'm trying to get at is this. In the traditional view of the hydrogen economy, the hydrogen is just an energy carrier, and in fact we "lose" a crapload of energy making and transporting the hydrogen. Isn't this just a variation of that, where the aluminum-gallium alloy becomes the energy carrier instead of the hydrogen?

[Sikon]

One thing I'm wondering about. We're taking doped aluminum and turning it into alumina to make hydrogen, then refining the alumina back into aluminum to start the process all over again. The refining process as I understand it involves electrolysis and a crapload of electricity.

What I'm trying to get at is this. In the traditional view of the hydrogen economy, the hydrogen is just an energy carrier, and in fact we "lose" a crapload of energy making and transporting the hydrogen. Isn't this just a variation of that, where the aluminum-gallium alloy becomes the energy carrier instead of the hydrogen?

Yes, replacing more direct storage of hydrogen on the vehicles (e.g. no pressurized hydrogen tanks or metal hydrides) by carrying around the aluminum-gallium metal plus water to produce the hydrogen onboard.

Of course, there are energy losses, although today's gasoline vehicles aren't super-efficient either, not more than a few percent efficiency overall, for reasons varying from most internal combustion vehicle engines being <= ~ 25% starting efficiency to the basic inefficiency of a several thousand pound vehicle being moved around to transport typically one ~ 100-kg person.

But it's better environmentally to have X amount of nuclear energy or other clean electricity consumed even with Y * X amount "wasted" than to have Z amount of fossil-fuel gasoline consumed, for the relative values of X, Y, and Z plausible to occur. Again, I'm not saying this in particular is the best method compared to other clean alternatives, just describing how it could work.