In 2012, NORCOWE partners together with Marintek initiated a project proposal combining the joint competencies in the centre to look into reducing the cost of installing wind turbines offshore. The project “Decision support for installation of offshore wind turbines” (DECOFF) started in 2013 as a 3 year knowledge building project supported by Statoil and the Norwegian Research Council. A main idea in the project has been to base the decisions on the equipment responses due to the weather rather than on conservative weather parameter limits, and thereby potentially improve the weather windows. Project partners were Christian Michelsen Research (project owner), MET Norway, Aalborg University, Uni Research, MARINTEK, University of Bergen and Statoil. Statoil took an active part in the project and served as work package manager for one of the work packages.
The project considered the following topics: Improved weather forecasting through calibration with measurements, downscaling of weather forecasts, modelling of selected installation operations in the non-linear time domain simulator SIMO (developed by Marintek), statistical modelling of the probability of exceeding critical limits, and finally integration of the above into a prototype online decision support tool.
Using a virtual test case, the project has shown that the method performs better or at least as well as the standard method. Results have been presented at Science Meets Industry in 2015, and at DeepWind’2016, and will be presented at Science Meets Industry in Stavanger.
The upper part of the figure shows a time series of the significant wave height. Each line correspond to an ensemble member of an ensemble prediction forecast. The blue line in the lower part of the figure is a time series of the computed operation failure rate, based on the output from the equipment simulator. The threshold for the failure rate is set to 10-4, which gives a weather window between 18 and 32 hours.