We review recent developments and applications of computational modelling techniques in the field of materials for energy technologies including hydrogen production and storage, energy storage and conversion, and light absorption and emission. In addition, we present new work on an Sn ₂ TiO ₄ photocatalyst containing an Sn(II) lone pair, new interatomic potential models for SrTiO ₃ and GaN, an exploration of defects in the kesterite/stannite-structured solar cell absorber Cu ₂ ZnSnS ₄ , and report details of the incorporation of hydrogen into Ag ₂ O and Cu ₂ O. Special attention is paid to the modelling of nanostructured systems, including ceria (CeO ₂ , mixed Ce _x O _y and Ce ₂ O ₃ ) and group 13 sesquioxides. We consider applications based on both interatomic potential and electronic structure methodologies; and we illustrate the increasingly quantitative and predictive nature of modelling in this field.