We conclude that, for the adsorbent materials considered in Fig. , the reduction in the mass of the pressure vessel walls, enabled by reduced storage pressures provided by the adsorbents, does not compensate for the increased mass of adsorbent material. That is, an adsorbed Xe storage system does not provide weight savings compared to the bulk Xe storage system. Because the mass of the adsorbent dominates the tankage fraction, the tankage fraction is, to first order approximation, inversely related to the gravimetric saturation loading of xenon in the adsorbent [units: amount of Xe per mass of adsobent]. Our model suggests to, in pursuit of an adsorbent that can outperform the bulk storage system, search for adsorbents with a xenon saturation loading exceeding 94 mol Xe/kg adsorbent.