Wake losses are perceived as one of the largest uncertainties in energy production estimates (EPEs) for new offshore wind projects. In recent years, significant effort has been invested to improve the accuracy of wake models. However, it is still common for a standard wake loss uncertainty of 50% to be assumed in EPEs for new offshore wind farms. This paper presents a body of evidence to support reducing that assumed uncertainty. It benchmarks the performance of four commonly used wake models against production data from five offshore wind farms. Three levels of evidence are presented to substantiate the performance of the models:• Case studies, i.e. efficiencies of specific turbines under specific wind conditions; • Array efficiencies for the wind farm as a whole for relatively large bins of wind speed and direction; and • Validation wake loss, which corresponds to the overall wake loss within the proportion of the annual energy production where validation is possible.The most important result for predicting annual energy production is the validation wake loss. The other levels of evidence demonstrate that this result is not unduly reliant on cancellation of errors between wind speed and/or wind direction bins.All of the root-mean-squared errors in validation wake loss are substantially lower than the 50% uncertainty commonly assumed in EPEs; indeed, even the maximum errors are below 25%. It is therefore concluded that there is a good body of evidence to support reducing this assumed uncertainty substantially, to a proposed level of 25%.
In principle, appropriately designed floating support structures need not be more massive nor costly than the jackets or tripods being deployed in German North Sea waters and elsewhere. A number of significant challenges remain, not least the current limited operating experience but also the limited availability of comprehensive design and modelling capabilities, and demonstrated and widely applicable safe and cost-effectively installation methods. This paper assesses the prospects in terms of technology principles, challenges and the potential resource.
This paper reports on a feasibility study of potential floating structures suitable for wind turbines in shallow seas (around 50 m). It describes the concepts, the evaluation and the selection process and includes ancillary issues, such as grid connection and O & M. Finally, it reports detailed analysis of the concept selected as most suitable in the circumstances, namely, a ‘triple-floater’ construction. A main conclusion is that although, in this case, this technology may not yet be ready for commercial application, the gap to economic viability is closing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.