Computational modelling is a powerful tool for the study of gas–solid interactions, and can be used both to complement experiment and design new materials. For the modelling of gas adsorption by nanoporous media, a multiscale approach can be used, in which the molecular force fields required for Grand Canonical Monte Carlo (GCMC) simulations are derived from first-principles calculations. This can result in significantly enhanced accuracy, in comparison with conventional empirical force field-based GCMC methods. In this article, we review the application of this multiscale approach to the simulation of the adsorption of hydrogen, methane and carbon dioxide in Porous Coordination Frameworks (PCFs) for the purpose of gas storage for energy transportation and Carbon Capture and Storage (CCS) technology. We also define a scheme for the design of new materials with improved adsorption performance for the storage of these gases through the combination of multiscale simulation and experimental work, and discuss some of the issues regarding gas adsorption measurement accuracy in the context of the validation of simulation results using experimental data.