[norwaypinesavage]

"It probably costs more in energy to make the aluminum than the hydrogen would provide."

Of course. However, there have been proposals to use aluminum as a storage medium for energy. As a fuel, it is light weight and safe to store. It is nearly as good as gasoline. There is an abundant supply of bauxite and all you do is add energy. It is, however, much more expensive.

[OldGuard1]

Anything involving hydrogen is really wasteful. This probably even moreso. Plus, fuel cells cost hundreds of thousands of dollars for one big enough to run a car.