Hydrogen is the ideal energy carrier, it can be used to propel cars using fuel cells or even normal cars could be converted to use with hydrogen with only water as a by-product. The main obstacle is that hydrogen is very difficult to store, so the fundamental bottleneck to the use of this clean fuel is the lack of hydrogen storage materials that can be used in safe and reliable conditions.
Neutrons interact very strongly with hydrogen atoms, allowing the study of the properties of hydrogen storage materials in a detail that is not always available to other techniques. Most metals are transparent to neutrons, so Neutron Scattering techniques can be used under realistic operation conditions.
Neutron diffraction can precisely determine the structure of materials; Neutron spectroscopy can study the dynamics of hydrogen in unparalleled detail. Computer modelling and neutron scattering data is straightforward to compare, making modelling an ideal tool for a deeper understanding of the properties of materials.
Neutrons also study fuel cells, from catalyst to membranes, fuel cells are a vital part in the hydrogen economy, using fuel cells and hydrogen can increase the efficiency of motor vehicles by 50%!