The transition from fossil fuels to green renewable resources presents a key challenge: most renewables are intermittent and unpredictable in their nature. Energy storage has the potential to meet this challenge and enables large scale implementation of renewables. In this paper we investigated the dynamic performance of a specific Adiabatic Compressed Air Energy Storage (A-CAES) plant with packed bed thermal energy storage (TES). We developed for the first time a plant model that blends together algebraic and differential sub-models detailing the transient features of the thermal storage, the cavern, and the compression/expansion stages. The model allows us to link the performance of the components, in particular those of the thermal storage system, with the performance of the whole A-CAES plant. Our results indicate that an A-CAES efficiency in the range 60-70% is achievable when the TES system operates with a storage efficiency above 90%. Moreover, we show how the TES dynamic behaviour induces off design conditions in the other components of the A-CAES plant. Such device-to-plant link of performance is crucial: only through integration of TES model in the whole A-CAES model is possible to assess the benefits and added value of thermal energy storage. To the authors' knowledge the present study is the first of this kind for an A-CAES plant. (C) 2016 Elsevier Ltd. All rights reserved.