Chapter 8 - Wave Energy

Abstract

This chapter gives an overview of the wave energy sector and some of its fundamental principles, and an understanding of the challenges and possible solutions. The focus of the wave energy sector, though, is the conversion of ocean wind waves. These wind waves are formed by winds blowing across large areas of ocean, with the surface friction transforming the energy. There are two types of wave that the wave energy converter is interested in: swell waves and local wind seas. Swell waves are generated from distant storms, whereas local wind seas are generated much closer to the point of interest. The forecasting of waves is useful for estimating energy output in the longer term. Using prediction allows an even more accurate short-term estimate. Both of these factors could combine to allow wave energy to become a dispatchable energy resource. The wave energy resource can be measured at a particular location using a number of different instruments. The industry standard is usually a small floating buoy which follows the sea surface and records its own vertical displacement. This is then recorded onboard and also transmitted ashore via a suitable telemetry system. These devices usually record for a period of around 20 minutes to get a representative sample of the wave conditions. The drivers and context for energy are now diversity of generation and security of supply. Once wave energy devices can show their commercial potential, their integration into the mainstream energy market will follow swiftly.