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Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite observations are compared to selected offshore meteorological masts in the Baltic Sea and North Sea. The overall aim of the Norsewind project is a state-of-the-art wind atlas at 100 m height. The satellite winds are all valid at 10 m above sea level. Extrapolation to higher heights is a challenge. Mesoscale modeling of the winds at hub height will be compared to data from wind lidars observing at 100 m above sea level. Plans are also to compare mesoscale model results and satellite-based estimates of the offshore wind resource.
Polityka Energetyczna – Energy Policy Journal, 2018
This article, as far as possible based on the available literature, empirical measurements, and data from mesoscale models describes and compares expected wind conditions within the Baltic Sea area. This article refers to aspects related to the design and assessment of wind farm wind resources, based on the author's previous experience related to onshore wind energy. The consecutive chapters of this publication are going to describe the present state and the presumptions relating to the development of wind energy within the Baltic Sea area. Subsequently, the potential of the sea was assessed using mesoscale models and empirical data from the Fino 2 mast that is located approximately 200 kilometers away from the majority of areas indicated in the Polish marine spatial development plan draft of Poland for offshore wind farm development (Maritime Office in Gdynia 2018). In the chapter describing mesoscale models, the author focused his attention on the GEOS5.12.4 model as the source of Modern-Era Retrospective Analysis for Research and Application 2 data, also known as MERRA2 (Administration National Aeronautics and Space Agency, 28), which, starting from February 2016, replaced MERRA data (Thogersen et al. 2016) and have gained a wide scope of applications in the assessment of pre-investment and operational productivity due to a remarkable level of correlation with in-situ data. Model-specific data has been obtained for eight locations, which largely overlap with the locations of the currently existing offshore wind farms within the Baltic Sea area. A significant part of this publication is going to be devoted to the description of the previously mentioned Fino 2 mast and to the analysis of data recorded until the end of 2014 by using the said mast (Federal Maritime and Hydrographic Agency 2018). The analysis has been carried out by means using scripts made in the VBA programming language, making it easier to work with large chunks of data. Measurements from the Fino 2 mast, together with long-term mesoscale model-specific measurements can be used, to some extent, for the preliminary assessment of wind farm energy yield in the areas designated for the development of renewable energy in the Polish exclusive maritime economic zone (Maritime Office in Gdynia 2018). In the final part of this article, pieces of information on the forecasted Baltic Sea wind conditions, especially within the exclusive economic zone of Poland, are going to be summarized. A major focus is going to be put on the differences between offshore and onshore wind energy sources, as well as on further aspects, which should be examined in order to optimize the offshore wind power development.
Remote Sensing of Environment, 2015
The offshore wind climatology in the Northern European seas is analysed from ten years of Envisat synthetic aperture radar (SAR) images using a total of 9256 scenes, ten years of QuikSCAT and two years of ASCAT gridded ocean surface vector wind products and high-quality wind observations from four meteorological masts in the North Sea. The traditional method for assessment of the wind resource for wind energy application is through analysis of wind speed and wind direction observed during one or more years at a meteorological mast equipped with well-calibrated anemometers at several levels. The cost of such measurements is very high and therefore they are only sparsely available. An alternative method is the application of satellite remote sensing. Comparison of wind resource statistics from satellite products is presented and discussed including the uncertainty on the wind resource. The diurnal wind variability is found to be negligible at some location but up to 0.5 m s −1 at two sites. Synergetic use of observations from multiple satellites in different orbits provides wind observations at six times in the diurnal cycle and increases the number of observations. At Horns Rev M2, FINO1 and Greater Gabbard satellite and in situ collocated samples show differences in mean wind speed of −2%, −1% and 3%, respectively. At Egmond aan Zee the difference is 10%. It is most likely due to scatterometer data sampled further offshore than at the meteorological mast. Comparing energy density with all samples at Horns Rev M2 shows overestimation 7-19% and at FINO1 underestimation 2-5% but no clear conclusion can be drawn as the comparison data are not collocated. At eight new offshore wind farm areas in Denmark, the variability in mean energy density observed by SAR ranges from 347 W m −2 in Sejerøbugten to 514 W m −2 at Horns Rev 3. The spatial variability in the near-shore areas is much higher than at areas located further offshore.
2013
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Satellite images, spanning January 2005 to January 2012, from ESA's Envisat Advanced Synthetic Aperture Radar (SAR) were used to investigate the wind energy offshore Iceland. In total 2500 images were calibrated and the wind speed calculated using the CMOD5N geophysical model function, on a 1x1 km grid. The wind direction used was taken from the US Navy Operational Global Atmospheric Prediction System (NOGAPS) model. It has much lower spatial resolution and therefore the model wind directions are interpolated in space and time before performing the SAR-based wind retrieval. Off the northern coast this analysis resulted in around 400 overlapping images but only 200 off the more data sparse southern coast. Wind resource statistics of mean wind speed, Weibull scale and shape parameters, and energy density have been calculated using the Satellite-WAsP (S-WAsP) program. The individual wind maps from SAR reveal a multitude of atmospheric phenomena off the complex coastline, including lee effects and gap flows in the fjords. The wind resource statistics shows the mean wind speed to range from 5 to 8 m/s at 10 m height above the sea level. Specific areas for case study are being selected for further investigation. SAR-derived wind maps have the advantage of covering the coastal zone. Further offshore the SAR-derived winds will be compared to the NORA10 atmospheric model results and scatterometer winds. In Iceland the wind resources on land are promising for wind energy application but not yet exploited on a significant scale. This analysis of the offshore wind resource is useful as pre-feasibility study in case this cean energy resource is to be exploited at a later stage. The work is part of the Nordic Icewind project.
IEEE Journal of Oceanic Engineering, 2017
Identification of prominent sea areas for the efficient exploitation of offshore wind energy potential requires primarily the assessment and modeling of several aspects of the long-term wind climate. In this work, the offshore wind speed and wind direction climate of the Mediterranean Sea is analytically described, the corresponding offshore wind energy potential is estimated on an annual and seasonal basis, and candidate areas for potential offshore wind farm development are identified. The analysis is based on ocean surface wind fields obtained from the Blended Sea Winds product, provided by the U.S. National Oceanic and Atmospheric Administration (NOAA), from 1995 to 2014. The satellite data are evaluated with reference to buoy wind measurements in the Spanish and Greek Seas. Wind data analysis reveals areas in the western and eastern Mediterranean Sea with high mean annual wind speed combined with rather low temporal variability. The obtained results suggest that offshore wind power potential in the Mediterranean Sea is fairly exploitable at specific suitable locations, such as the Gulf of Lions (with mean annual wind power density up to ∼1600 W/m 2) and the Aegean Sea (with mean annual wind power density up to ∼1150 W/m 2), that are certainly worth further in-depth assessment for exploiting offshore wind energy. Finally, based on the available offshore wind resource potential and the water depth suitability, three specific sites (in the Gulf of Valencia and the Adriatic and Ionian Seas) are selected and the average wind power output for a specific wind turbine type is estimated. Index Terms-Blended sea winds, Mediterranean Sea, offshore wind energy, UpWind turbine. I. INTRODUCTION C URRENTLY, among renewable ocean energy resources, offshore wind energy has a leading role in a worldwide basis, since it is considered the most technologically advanced and mature ocean energy resource with regard to installed capacity, as well as policy and legislation frameworks. Without doubt Northern Europe has led the offshore wind Manuscript
2021
We validate a new high-resolution (3 km) numerical mesoscale weather simulation for offshore wind power purposes for the time period 2004-2016 for the North Sea and the Norwegian Sea. The 3 km Norwegian reanalysis (NORA3) is a dynamically downscaled data set, forced with state-of-the-art atmospheric reanalysis as boundary conditions. We conduct an in-depth validation of the simulated wind climatology towards the observed wind climatology to determine whether NORA3 can serve as a wind resource data set in the planning phase of future offshore wind power installations. We place special emphasis on evaluating offshore wind-power-related metrics and the impact of simulated wind speed deviations on the estimated wind power and the related variability. We conclude that the NORA3 data are well suited for wind power estimates but give slightly conservative estimates of the offshore wind metrics. In other words, wind speeds in NORA3 are typically 5 % (0.5 m s −1) lower than observed wind speeds, giving an underestimation of offshore wind power of 10 %-20 % (equivalent to an underestimation of 3 percentage points in the capacity factor) for a selected turbine type and hub height. The model is biased towards lower wind power estimates due to overestimation of the wind speed events below typical wind speed limits of rated wind power (u < 11-13 m s −1) and underestimation of high-wind-speed events (u > 11-13 m s −1). The hourly wind speed and wind power variability are slightly underestimated in NORA3. However, the number of hours with zero power production caused by the wind conditions (around 12 % of the time) is well captured, while the duration of each of these events is slightly overestimated, leading to 25-year return values for zero-power duration being too high for the majority of the sites. The model performs well in capturing spatial co-variability in hourly wind power production, with only small deviations in the spatial correlation coefficients among the sites. We estimate the observation-based decorrelation length to be 425.3 km, whereas the model-based length is 19 % longer.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2008
Remote sensing observations used in offshore wind energy are described in three parts: ground-based techniques and applications, airborne techniques and applications, and satellite-based techniques and applications. Ground-based remote sensing of winds is relevant, in particular, for new large wind turbines where meteorological masts do not enable observations across the rotor-plane, i.e., at 100 to 200 m above ground level. Light detection and ranging (LiDAR) and sound detection and ranging (SoDAR) offer capabilities to observe winds at high heights. Airborne synthetic aperture radar (SAR) used for ocean wind mapping provides the basis for detailed offshore wind farm wake studies and is highly useful for development of new wind retrieval algorithms from C-, L-, and X-band data. Satellite observations from SAR and scatterometer are used in offshore wind resource estimation. SAR has the advantage of covering the coastal zone where most offshore wind farms are located. The number of samples from scatterometer is relatively high and the scatterometer-based estimate on wind resources appears to agree well with coastal offshore meteorological observations in the North Sea. Finally, passive microwave ocean winds have been used to index the potential offshore wind power production, and the results compare well with observed power production (mainly land-based) covering nearly two decades for the Danish area.
2024
The essay argues –based on a close study of the past century --for doses of rationality and soul-searching in the ongoing battle for minority rights and dignity. It urges India's Muslim communities to make their own contribution to invest in secularising India, and underlines that minority communalism is no antidote to majoirtarianism.
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