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.