To support concept studies aimed at assessing offshore wind technology, we developed the specifications of a representative utility-scale multimegawatt turbine now known as the "NREL offshore 5-MW baseline wind turbine." This wind turbine is a conventional three-bladed upwind variable-speed variable blade-pitch-to-feather-controlled turbine. To create the model, we obtained some broad design information from the published documents of turbine manufacturers, with a heavy emphasis on the REpower 5M machine. Because detailed data was unavailable, however, we also used the publicly available properties from the conceptual models in the WindPACT, RECOFF, and DOWEC projects. We then created a composite from these data, extracting the best available and most representative specifications. This report documents the specifications of the NREL offshore 5-MW baseline wind turbine-including the aerodynamic, structural, and control-system properties-and the rationale behind its development. The model has been, and will likely continue to be, used as a reference by research teams throughout the world to standardize baseline offshore wind turbine specifications and to quantify the benefits of advanced land-and sea-based wind energy technologies. vii

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 waves, sea current, hydrodynamics, and foundation dynamics of the support structure. The sophistication of these aero-hydro-servo-elastic codes, and the limited data available with which to validate them, underscore the need to verify their accuracy and correctness. The Offshore Code Comparison Collaboration (OC3), which operates under Subtask 2 of the International Energy Agency (IEA) Wind Task 23, was established to meet this need.To test the newly developed codes, the main activities of OC3 were to (1) discuss modeling strategies, (2) develop a suite of benchmark models and simulations, (3) run the simulations and process the simulation results, and (4) compare and discuss the results. These activities fell under broader objectives including:• Assessing the accuracy and reliability of simulations to establish confidence in their predictive capabilities • Training new analysts to run and apply the codes correctly • Identifying and verifying the capabilities and limitations of implemented theories • Investigating and refining applied analysis methodologies • Identifying further research and development (R&D) needs.Such verification work, in the past, led to dramatic improvements in model accuracy as the code-to-code comparisons and lessons learned helped identify model deficiencies and needed improvements. These results are important because the advancement of the offshore wind industry is closely tied to the development and accuracy of system-dynamics models.The OC3 project was performed through technical exchange among a group of international participants from universities, research institutions, and industry across the United States of America, Germany, Denmark, the United Kingdom, Spain, the Netherlands, Norway, Sweden, and Korea. Moreover, most of the aero-hydro-servo-elastic codes developed for modeling the dynamic respon...

This report, the 2016 Offshore Wind Energy Resource Assessment for the United States, was developed by the National Renewable Energy Laboratory (NREL), and updates a previous national resource assessment study (Schwartz et al. 2010), and refines and reaffirms that the available wind resource is sufficient for offshore wind to be a large-scale contributor to the nation's electric energy supply. Experience from other renewable technologies, such as landbased wind and solar energy, indicates that offshore wind site development will likely be highly selective. Therefore, the resource potential needs to significantly exceed the anticipated deployment to allow for siting flexibility. When developers and regulators have more siting options, projects can be built in the most economical and least conflicted areas. Therefore, an abundant wind resource is one of the essential building blocks that compose the value proposition for offshore wind. As such, the study shows that to implement the U.S. Department of Energy's (DOE's) Wind Vision 86-gigawatt (GW) offshore wind deployment scenario for 2050 (DOE 2015a), it would require the United States to use about 0.8% of the gross resource area or about 4.2% of the total technical resource area.

This paper was selected for presentation by an OTC Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Papers presented at OTC are subject to publication review by Sponsor Society Committees of the Offshore Technology Conference. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Offshore Technology Conference is prohibited.

No abstract