IEA Wind Task 23 Offshore Wind Technology and Deployment

Preface This final report for IEA Wind Task 23, Offshore Wind Energy Technology and Deployment, is made up of two separate reports, Subtask 1: Experience with Critical Deployment Issues and Subtask 2: Offshore Code Comparison Collaborative (OC3). Subtask 1 discusses ecological issues and regulation, electrical system integration, external conditions, and key conclusions for Subtask 1. Subtask 2, included here, is the larger of the two volumes and contains five chapters that cover background information and objectives of Subtask 2 and the results from each of the four phases of the project. United States. Presentations covered both detailed research topics and more general descriptions of current situations in the countries. After the meeting, the IEA Wind ExCo approved Annex 23 (Task 23) to the Implementing Agreement as a framework for holding additional focused workshops and developing research projects. The work would increase understanding of issues and develop technologies to advance the development of wind energy systems offshore. By 2008, 10 countries had chosen to participate in this task, and many research organizations in these countries are sharing their experiences and conducting the work (Table 1). This annex was organized into two subtasks to (1) give the participants experience with critical deployment issues, and (2) conduct technical research for deeper water applications. The results of this work are presented in the Executive Summary and in the supporting two volumes of this report. The vast offshore wind resource represents a potential to use wind turbines installed offshore to power much of the world. Design standardization is difficult, however, because offshore sites vary significantly through differences in water depth, soil type, and wind and wave severity. To ensure that offshore wind turbine installations are cost effective, the use of a variety of support structure types is required. These types include fixed-bottom monopiles, gravity bases, and space-frames—such as tripods and lattice frames (―jackets‖)—and floating structures. In this context, the offshore wind industry faces many new design challenges. Wind turbines are designed and analyzed using simulation tools (i.e., design codes) capable of predicting the coupled dynamic loads and responses of the system. Land-based wind turbine analysis relies on the use of aero-servo-elastic codes, which incorporate wind-inflow, aerodynamic (aero), control system (servo), and structural-dynamic (elastic) models in the time domain in a coupled simulation environment. In recent years, some of these codes have been expanded to include the additional dynamics pertinent to offshore installations, including the incident …