A Comparative Study of Battery, Supercapacitor and Undersea Energy Storage Systems in Wave Energy Applications

A technical comparison between two standard energy storage technologies, i.e. battery and supercapacitor (SC), and a novel alternative, i.e. undersea energy storage system (UESS), in wave energy applications is presented. Various sea states with different significant wave heights are considered for investigating the efficiency and lifetime of the storage devices. Comparisons are carried out assuming that the storage device operates in parallel with a wave energy converter to deliver fixed power, i.e., average harvested wave power, to the grid during a designated period of time. While battery and SC outperform the UESS in terms of efficiency, extreme oversizing is required for achieving lifetime periods that satisfy maintenance and reliability requirements, however.