Software defined network (SDN) can effectively improvethe performance of traffic engineering and will be widely used inbackbone networks. Therefore, new energy-saving schemes musttake SDN into consideration; this action is extremely importantowing to the rapidly increasing energy consumption in telecom andInternet service provider (ISP) networks. Meanwhile, the introductionof SDN in current networks must be incremental in mostcases, for technical and economic reasons. During this period, operatorsmust manage hybrid networks in which SDN and traditionalprotocols coexist. In this study, we investigate the energyefficienttraffic engineering problem in hybrid SDN/Internet protocol(IP) networks. First, we formulate the mathematical optimizationmodel considering the SDN/IP hybrid routing mode. Theproblem is NP-hard; therefore, we propose a fast heuristic algorithmnamed hybrid energy-aware traffic engineering (HEATE) asa solution. In our proposed HEATE algorithm, the IP routers performshortest-path routing by using distributed open shortest pathfirst (OSPF) link weight optimization. The SDNs perform multipathrouting with traffic-flow splitting managed by the global SDNcontroller. The HEATE algorithm determines the optimal settingfor the OSPF link weight and the splitting ratio of SDNs. Thus, thetraffic flow is aggregated onto partial links, and the underutilizedlinks can be turned off to save energy. Based on computer simulationresults, we demonstrate that our algorithm achieves a signifi-cant improvement in energy efficiency in hybrid SDN/IP networks.