Floating wind turbines

Floating offshore wind turbines have great potential as they are not limited by the same conflicts of interest as the onshore and the near-shore offshore turbines. Furthermore, wind farm developers have greater... 

Larsen, K. (2010), Hywind floating offshore wind turbine foundation . Wind Power, Renewable Energy Focus Magazine, 22 March 2010, (accessed 14 March 2011). 

Over the analysed wind turbine life time of 20 years its components are replaced completely at least once and considered as new after that (see Table 7). This planned component replacement is carried out for all four strategy options. This means that maintenance measures aim to keep downtime as a result of unplanned outages or maintenance as low as possible. A component replacement is not possible during the winter half year. If a replacement is due in a winter half year, it is waited until the summer half year begins to start the replacement. A replacement of a component requires a floating crane. 

Weinzettel J., Reenaas M., Solli C. and Hertwich E G. (2009) Life cycle assessment of a floating offshore wind turbine , Renew Energy, Vol.34, pp.742-747. 

Reynolds numbers are of value in the various fields because lesis of models are directly comparable to full-scale results of geometrically similar shapes if the Reynolds ratio for the model equals that of the actual or full-scale project. This has its practical applications in the field of hydrodynamics, in the study of water resistance of hulls or floats, and in the study of water velocities, levee problems, etc., of large rivers. It is used also to establish the best proportions of hydraulic turbines through the use of models. Much of the science of aeronautics rests upon experimental data obtained in wind tunnels. Dangerous inaccuracies might exist in drawing conclusions for actual construction from model tests, unless either the model were, tested at a Reynolds number equal to that of the completed project, or due corrections and allowances were made for the Reynolds number. See also Heat Transfer. 

A ship or a floating crane is only sent to the turbine if the wind is calm. If the wind is not calm, it is waited until it is calm. The trip duration is according to the weather condition. If the turbine is not accessible when the ship or crane arrives, it needs to idle nearby the turbine until it is accessible again. The return trip to the service harbour starts only if the weather condition is well. 

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