Floating lidar was introduced in 2009 as an offshore wind measurement technology focusing on the specific needs of the wind industry with regard to wind resource assessment applications. Floating lidar systems (FLS) are meant to replace an offshore met mast, being significantly cheaper and saving an essential part of project upfront investment costs. But at the same time, they need to overcome particular challenges—these are (1) the movement of the sea imparting motion on the buoy and the lidar, and the subsequent challenge of maintaining wind speed and direction accuracy, and (2) the remoteness of the deployed system in an extremely challenging environment necessitating robust, autonomous and reliable operation of measurement, power supply, data logging, and communication systems. The issue of motion influences was investigated in a number of studies and is to be checked and monitored in offshore trials of individual FLS realizations. In trials to date, such influences have been demonstrated to be negligibly or manageably small with the application of motion reduction or compensation strategies. Thereby, it is possible to achieve accurate wind measurement data from FLS. The second kind of challenge is tackled by implementing a sufficiently robust and reliable FLS design. Recommended practices collected by a working group within the International Energy Agency (IEA) Wind Task 32 and within the UK offshore wind accelerator program offer guidance for FLS design and configuration, and furthermore set requirements for trialing the system types and individual devices in representative offshore conditions. WIREs Energy Environ 2017, 6:e250. doi: 10.1002/wene.250 This article is categorized under: Wind Power > Science and Materials Wind Power > Climate and Environment

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%.

Fast engineering wake models are the backbone of wind farm annual energy production (AEP) estimators, whereas the addition of induction zone models in existing tools is a more recent response to rising concerns over wind farm blockage associated losses. Here, “blockage” describes the combined induction fields of all wind turbines inside a farm. Unlike the term might suggest, blockage not only reduces flow speeds, but also increases them; for instance along the outer edges of wind farms. Evaluating the overall impact on AEP of these gains and losses necessitates accurate wind farm induction models. Whilst engineering wake models are tuned to predict wind farm performance, existing induction zone models are all derived for accurately predicting the near field induction not the far field value—important for wind farm simulations. This paper presents the induction models implemented in the wind farm simulation tool PyWake, as well as results from novel analytical models and compares their far field predictions to RANS-AD simulations of different turbines. We demonstrate that when including blockage in AEP simulations, the downstream speed-ups need to be included to avoid an unrealistic bias toward AEP loss and that wake expansion significantly impacts induction at rated thrust levels.

The Trial of the Major War Criminals at Nuremberg, the personalities associated with the trial, the verdicts rendered, and criticisms directed toward both those verdicts and the tribunal itself have generated a multitude of historical works. However, few historians have explored the American print media's coverage of the trial and even fewer have studied how a newspaper's disposition towards the trial reflected that publication's political ideology and influenced the newspaper's coverage of the trial itself. For this reason, it is the objective of this thesis to examine this neglected area, thus contributing to the scholarship of the first Nuremberg Trial. The newspapers chosen for assessment reflect varying degrees of ideological affiliation and are somewhat diverse geographically. Of the five publications selected, two, The Wall Street Journal and Chicago Daily Tribune, were recognized to be solid supporters of the political right. Likewise, during the period examined, the other publications, The New York Times, The Washington Post, and Los Angeles Times, were considered politically moderate to liberal in their ideology. This study examines editorials, columns (both unique to the specific publication and those syndicated nationally), and letters to the editor dedicated to the trial, in conjunction with the actual reports filed by the newspaper's correspondents and wire services. This thesis also examines the regularity of each newspaper's coverage of the trial and its selection of the information published within its pages, including a comparison with the other publications. After an intense examination of the materials listed above, this study finds that there exists a strong correlation between the political ideology associated with the individual newspapers and their disposition towards the trial, a bias that often manifested itself in the newspaper's coverage of the proceedings. As one might expect, those publications considered traditionally moderate to liberal endorsed the trial and viewed it as a positive step towards strengthening international law and establishing global security. Those newspapers often identified as being politically conservative questioned the trial's legitimacy, believing that its mechanisms were anathematic to western legal principles and infringed on national sovereignty.

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