Geocooling and thermal energy storage (TES) are two strategies that could help alleviate the energy and carbon emission burden from cooling commercial buildings. This simulation study analyses the potential for geocooling, both with and without TES, in a Mediterranean climate. Spherically-encapsulated phase change material (PCM) was used as the thermal storage medium in the TES system. A PCM TES tank model was developed and validated within the TRNSYS environment. Using a small, lightweight commercial building as a case study, it was found that electricity savings of between 24 and 45% are possible from combining geocooling with TES, when compared to a system based on a reference ground-source heat pump (GSHP). (C) 2017 Elsevier Ltd. All rights reserved.