We now investigate how our approximation, bulk density of the nanoporous material ρ ads ≈ crystal density, influences our results. This is important because, in our model, ρ ads is used for two The measured bulk/tap densities of CC3, HKUST-1, and Ni-MOF-74 reported in Ref. are shown in Fig. . We now use these bulk/tap densities for ρ ads to investigate how the tankage fraction changes, compared to when we used the crystal density for ρ ads (listed in Fig. ) as in Fig. . Fig. shows that, for these three materials for which the bulk density was available: when using the more realistic bulk density ρ ads as input to the model, the optimal storage pressures are reduced, but, the tankage fraction changes only marginally. I.e., the approximation bulk density ≈ crystal density is unlikely to significantly influence our conclusion that the adsorbed storage systems we considered do not provide lower tankage fractions than a bulk storage system.