Improving the Techno-Economic Performance of Wave Energy Converters

Abstract

Ocean wave energy has a huge potential to make a contribution to global energy transition. However, the high Levelized Cost of Energy (LCOE) is currently a big hurdle to the development of wave energy converters (WECs). This thesis is motivated to improve the techno-economic competitiveness of WECs. It focuses on the effects of systematic sizing of WECs. "Systematic sizing" is reflected in this thesis by considering the effects of sizing on the two main components of WECs, namely the buoy and PTO system. The main body of this thesis starts with a literature review. First, it is intended to provide an overview of current wave energy technologies and the application of power take-off (PTO) systems. Secondly, the studies relevant to sizing of WECs are reviewed, and sizing methods used in the context are discussed and compared. It indicates that the existing studies mainly focus on the effects of buoy sizing and there is a lack of consideration of PTO sizing. In addition, the sizing methods based on the Budal diagram and Froude scaling can only be used to conduct sizing of buoy but the influence of PTO sizing cannot be covered. Numerical simulation can be applied to take into account both effects of buoy sizing and PTO sizing, but it is usually associated with low computational-efficiency. As sizing can be regarded as a kind of optimization which normally requires a number of iterations, an efficient method is beneficial for accelerating the design process of WECs. Followed up by the literature review, Chapter 3 to Chapter 7 of this thesis are dedicated to accomplishing two main research objectives...