The Benefits of Device Level Short Term Energy Storage in Ocean Wave Energy Converters

This chapter presents an outline of the requirements for, and the benefits of, short term energy storage at the level of individual wave energy devices, in the field of ocean wave energy conversion. A general background introduction to ocean renewable energy from the perspective of industry growth and incentives, as well as an overview of the different technology types is provided. The unique and challenging features of the short term variability of wave energy is presented and its implications for equipment and grid connectivity are outlined. Short term energy storage is considered as a possible element in the amelioration of this fluctuating output. A case study of a supercapacitor based storage system is presented for an oscillating water column type wave energy device. The issue of supercapacitor lifetime is then addressed in a comprehensive manner in conjunction with results from a lifetime testing rig. Finally, some of the ancillary benefits associated with such a short term energy storage system are briefly described.