In this paper, a unified adaptive energy management scheme (EMS) is proposed for renewable-interfaced hybrid energy storage system (HESS) under grid connected/islanded conditions. A second harmonic based phased locked loop is employed for effective synchronization/resynchronization of the microgrid system under contingency conditions. The operation and management of the microgrid system under both these modes are accomplished by an efficient adaptive power management algorithm. A quantitative analysis on the HESS performance is provided in order to investigate the effectiveness of the proposed approach. Load curtailment and off-maximum power point tracking features are also accommodated in the proposed scheme. This approach address seamless transfer between the various sub-modes of the system along with additional services such as power quality enhancement and effective power dispatch between various sources. The effectiveness of the proposed scheme is verified by both simulation and experimental investigations.