selection is thus changed and broadened by the introduction of nanophase materials to the menu of materials to choose from it is a further object of this invention to improve operating and economic characteristics of hydride systems the ability to custom design nanophase grain diameter shapes and crystalline structure together with the many combinations of materials mixtures and alloys of materials useful for hydrides not only boosts hydrogen storage capability by weight and volume density but also greatly broadens the available range of materials and properties available the result permits optimizing some or all of the various other hydride operating and economic characteristics such as but not limited to materials costs flow rates speed of response pressure and temperature relationships and various other operating characteristics of hydride storage systems in this invention 39 s preferred embodiment nanophase materials store hydrogen as a hydride various combinations of nanophase diameters and nanophase materials or combinations of materials including mixtures and alloys of materials with the same or different nanophase diameters can be designed to optimize at least many or combinations of the following characteristics of hydride storage systems a weight density i e the total weight of the hydrogen and hydride metal in terms of deliverable energy stored while the density of hydrogen by volume in a conventional hydride is high the density by weight is much lower because of the weight of the associated metal conventional hydrides at best are about four to five times heavier than gasoline because of the weight of the metals the penalty would be still greater except that hydrogen alone has three times the energy density of gasoline weight is especially.