RIASSUNTO
ABSTRACT
Both offshore wind energy and offshore aquaculture are developing rapidly and moving into deeper waters to acquire better resources. Meanwhile, the offshore solar energy is also drawing more and more attention from the academic communities. A novel concept of a floating wind-solar-aquaculture (WSA) system, combining multiple megawatt (MW) vertical-axis wind turbines (VAWTs) and solar arrays with a floating steel fish-farming cage, is presented. The WSA aims to exploit the marine resources more effectively, while significantly shorten the payback period of investment in offshore wind turbines. The details of WSA are described in this study.
An aerodynamic source code based on the double multi-streamtube theory is developed. It can be exported into the commercial software Orcaflex to achieve fully coupled analysis of the WSA system. Using the developed tool, turbine aerodynamic performance, tower base bending moments, global WSA motions, and tension of mooring lines are investigated. The results affirm that WSA is technically safe and feasible. It is a promising concept to deploy in intermediate and deep waters.
INTRODUCTION
The increasing interest in exploitation of wind and solar energy resources has lasted for decades because they are easily available, sustainable, and pollution free. These two energy resources are abundant in offshore seas. To date a great number of bottom-fixed horizontal-axis wind turbines (HAWTs) are deployed in offshore regions of water depth less than 40m, due to the commercial success of HAWTs onshore (Cahay et al., 2011). However, since offshore wind farms are moving to deeper waters, floating wind turbines must be adopted to reduce the high installation cost of foundations. On the other hand, to better exploit water resources, the offshore aquaculture industry is also developing rapidly and entering deep waters. The industries of offshore wind and aquaculture seem irrelevant, but in reality they can be delicately integrated to improve utilization of marine space.