Abstract The solar thermal energy could be stored and reused at a desired locations and conditions. The prerequisite is to develop a suitable media which could able to store the solar thermal energy reversibly. The metal-metal hydride system could be one of the option to store the thermal energy in the form of metal and hydrogen which on recombination will form metal- hydride and release the stored thermal energy with high efficiency. Besides the high hydrogen storage capacity, the ultrafast hydrogenation-dehydration kinetics is desirable for the viable commercial applications. In connection to this, magnesium – magnesium hydride system has been considered as a potentials candidate. However, the sluggish hydrogenation-dehydrogenation kinetics is an issue. In the present study nano-engineered Mg-V composite has been developed using MgH2 and V2O5 as a precursor for magnesium and vanadium, respectively. The composite has shown an ultrafast hydrogenation-dehydrogenation kinetics at remarkable low temperature. The hydrogenation of composite has efficiently released the thermal energy. The hydrogenated composite could be dehydrogenated using compact solar power (CSP) even below 200 °C.