  Since the current transportation sector is the largest consumer of oil, and
subsequently responsible for major air pollutants, it is inevitable to use
alternative renewable sources of energies for vehicular applications. The
hydrogen energy seems to be a promising candidate. To explore the possibility
of achieving a solid-state high-capacity storage of hydrogen for onboard
applications, we have performed first principles density functional theoretical
calculations of hydrogen storage properties of beryllium oxide clusters
(BeO)$_{n}$ (n=2 -- 8). We observed that polar BeO bond is responsible for
H$_{2}$ adsorption. The problem of cohesion of beryllium atoms does not arise,
as they are an integral part of BeO clusters. The (BeO)$_{n}$ (n=2 -- 8)
adsorbs 8--12 H$_{2}$ molecules with an adsorption energy in the desirable
range of reversible hydrogen storage. The gravimetric density of H$_{2}$
adsorbed on BeO clusters meets the ultimate 7.5 wt% limit, recommended for
onboard practical applications.
  In conclusion, beryllium oxide clusters exhibit a remarkable solid-state
hydrogen storage.
