5. Conclusion

Whether in direct combustion, combustion engines or fuel cells, this article shows that the use of hydrogen is benefiting from a large number of real advances. When necessary, transporting gaseous hydrogen by pipeline and liquid hydrogen by truck or sea remains the most rational solution, even if it requires considerable investment. Finally, in terms of storage, certain solutions are already becoming widespread:

• liquid hydrogen for large quantities for stationary use or for propulsion of ships, trains and heavy vehicles;

• High-pressure compressed hydrogen gas for medium quantities, especially for light vehicles;

• hydrogen stored in solids for small quantities.

The result is that hydrogen or, better still, "green" hydrogen, a fuel produced...