AfCommuter, it would require a *ton* of electricity to fix hydrogen on a large scale. Electricity production is quite dirty, using coal for the most part. Hydro power is big, but there are drawbacks. Ask the salmon.

It's incorrect to say that the oil found in the earth is finite, but the levels at which we pump will not continue unabated, meaning that the amount we pump per day will start decreasing as formerly 'full' oil wells are drawn down and then, finally, depleted.
The amount of newly created wells to depleted wells is not a 1:1 ratio, and that ratio will tip further in the 'wrong' direction in the future. It's not sustainable at our current rate of use.