With　tremendous　growth　in　bandwidth　demand,　energy　consumption　problem　in　elastic　optical　networks　(EONs)　becomes　a　hot　topic　with　wide　concern.　The　sliceable　bandwidth-variable　transponder　in　EON,　which　can　transmit/receive　multiple　optical　flows,　was　recently　proposed　to　improve　a　transponder＇s　flexibility　and　save　energy.　In　this　paper,　energy-efficient　routing,　modulation　and　spectrum　allocation　(EE-RMSA)　in　EONs　with　sliceable　bandwidth-variable　transponder　is　studied.　To　decrease　the　energy　consumption,　we　develop　a　Mixed　Integer　Linear　Programming　(MILP)　model　with　corresponding　EE-RMSA　algorithm　for　EONs.　The　MILP　model　jointly　considers　the　modulation　format　and　optical　grooming　in　the　process　of　routing　and　spectrum　allocation　with　the　objective　of　minimizing　the　energy　consumption.　With　the　help　of　genetic　operators,　the　EE-RMSA　algorithm　iteratively　optimizes　the　feasible　routing　path,　modulation　format　and　spectrum　resources　solutions　by　explore　the　whole　search　space.　In　order　to　save　energy,　the　optical-layer　grooming　strategy　is　designed　to　transmit　the　lightpath　requests.　Finally,　simulation　results　verify　that　the　proposed　scheme　is　able　to　reduce　the　energy　consumption　of　the　network　while　maintaining　the　blocking　probability　(BP)　performance　compare　with　the　existing　First-Fit-KSP　algorithm,　Iterative　Flipping　algorithm　and　EAMGSP　algorithm　especially　in　large　network　topology.　Our　results　also　demonstrate　that　the　proposed　EE-RMSA　algorithm　achieves　almost　the　same　performance　as　MILP　on　an　8-node　network.　(C)　2017　Elsevier　Inc.　All　rights　reserved.