Electrical energy storage systems

This chapter examines electrical energy storage systems (ESSs) for wave energy converters (WECs). The motivations for including on-board energy storage are outlined in terms of power smoothing, low-voltage ride-through (LVRT) and ancillary services. Various wave energy converter technologies are explored as well as their inherent energy storage mechanisms. Electrical energy storage technologies, including batteries, capacitors, and supercapacitors, are then compared. Two case studies are described where electrical energy storage, namely supercapacitor energy storage, is applied to help smooth the output power from a WEC. The first case study examines power smoothing for a SEAREV WEC and the second case studies explores smoothing the output power from an offshore oscillating water column (OWC) WEC operated at variable speed.