Hydrogen is often called the fuel of the future because it contains no Carbon (and therefore produces no CO2) and it can be made from water.
However there are considerable problems to be overcome:
- the amount of energy required to make it, by separating the Hydrogen and Oxygen in water,
- its highly explosive nature when mixed with oxygen
- its very low density (the lightest material in the universe!) and consequent low energy density
So it is likely to be some years before it becomes a serious contributor. Nevertheless, Auto manufacturers are already working hard on the technology to use Hydrogen in internal combustion engines, and in the longer term in fuel cells, which produce electricity directly from the fuel, without burning, making it more efficient and much cleaner than a combustion engine.