aluminum used to create hydrogen for a transport fuel.

So in the case of fuel-cell cars using electric motors, you use electric current to electrolyze bauxite to make aluminium, then you cut the metal up into pellets, then you transport them to the users, who drop them into water to make hydrogen and oxygen which are used in fuel cells to make electric current? I wonder if taking the electricity to the user using a grid and using it to charge a battery would be more efficient?

Yes, more or less. You make an aluminum/gaium alloy into pellets, which are dropped into water. The alloy takes the oxygen from the water molecule releasing the hydrogen.

If course it's all dependent on using renewable energy to create the electricity in the first place.

The problem with electric engines is the short range and the long charging time.

Im assuming these pellets eventually dissolve but correct that if I'm mistaken.

If they do dissolve is there any waste or need to drain the water?

Is there any remaining pellet pieces?

How long do they last? (If dissolve)

How large are these pellets?

Is there any environmental impact on making the alloy?

Would it strain current aluminium demand?

The aluminum is changed into alumina or aluminium oxide and is recycled easily. The gallium is unchanged and is easily recovered and used again.

The point I was trying to get at was;

How much hydrogen is extracted per pellet over time?

If the pellets dissolve fast it increases consumption of aluminum which increases the cost because demand goes up. This impacts weather it's cost effective or not.

I can't personally attest to the efficacy of the process described here for creating free hydrogen from aluminum and gallium, however I do know that a great deal of energy (usually in the form of electrical power) is required to create free aluminum in the first place.

Hydrogen is a potentially wonderful fuel, which can easily be made to work in most modern engines, however, though hydrogen is abundant in water, free hydrogen is not found in nature, and it takes more energy to separate it from water than is released in oxidizing (burning) it.

The efficiency of current renewable energy sources isn't great enough to make this economically worthwhile.

Thank you.

Gallium induced structural failure of Coke can.

https://m.youtube.com/watch?v=FaMWxLCGY0U