Floating 2-MW Turbine Prototype Tests Feasibility of Harnessing Offshore Wind

Abstract

This article, written by Editorial Manager Adam Wilson, contains highlights of paper OTC 23492, ’Implementation of a 2-MW Floating Wind Turbine Prototype Offshore Portugal,’ by Christian A. Cermelli, Marine Innovation & Technology, and Dominique G. Roddier and Alla Weinstein, Principle Power, prepared for the 2012 Offshore Technology Conference, Houston, 30 April-3 May. The paper has not been peer reviewed. A 2-MW floating offshore wind system prototype was implemented off the coast of Portugal. The project was designed to prove the technical and economic feasibility of floating offshore wind turbines in southern Europe. It is based on the WindFloat concept, a three-column semisubmersible-platform design with water-entrapment plates. Such technology enables deployment of multimegawatt wind-turbine generators at great distances from shore, in any water depth. Synergies with offshore oil and gas platforms have been exploited; however, deployment in an area with no previous offshore oil and gas activities led to unique challenges. Project Design Bases The project design bases were driven by the following principle: The floating wind turbine should be large enough to provide meaningful testing of fabrication, installation, and operation capabilities. Some of the main project design bases were A location in 49-m-deep water, 6 km offshore Aguçadoura, a small town located north of Porto on the west coast of Portugal A wind-turbine size from 2 to 2.3 MW A connection to the country’s main power grid Although no specific targets were set for local content, the drive to maximize work performed locally was also seen as a critical success factor for the project. Previous testing conducted during earlier feasibility studies was performed at a 1/67 scale in a model-testing facility. Intermediate-scale testing (between in-door controlled-environment testing in a wave tank and full-scale prototype) was not seen as a necessary step. Commercial development of floating wind farms will likely be based on the largest available wind turbines. Currently, 3- to 6-MW machines are available for the offshore market; however, because of budgetary limitations and limited experience with wind turbines of such size, the more common and lower-capacity 2- to 2.3-MW turbines were considered optimal for this project. A testing site 6 km off the west coast of Portugal was selected because of the presence of a subsea electrical cable with sufficient capacity to transport power from the WindFloat prototype to shore. The target design life for the plat-form is 5 years, but planned operation should not exceed 2 years.