Browsing by Author "Pontes, M.T."
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- Assessing the wave energy resource using remote sensed dataPublication . Pontes, M.T.; Bruck, M.; Lehner, S.The use of accurate remote sensed wave data in the coastal area (water depth up to 80m) will enable a high quality characterization of the wave energy resource. Work has been carried out with this objective for a number of years namely assessing the quality of the radar altimeter and SAR sensors data. In this paper a summary of the quality of wave period estimates from the NASA/CNES Jason radar altimeter is presented, showing that the analytical models that have been proposed in recent years provide already accurate results. This paper also includes a verification of ESA ENVISAT SAR data (height, period and direction parameters in addition to the shape of frequency spectra) against NDBC buoy data, which has shown good accuracy for wave energy resource assessment. However, the long Exact-Repeat-Period of NASA (10 days) and of ESA satellites (35 days) poses serious limitation to the usefulness of their wave measurements except for long-term wave climate assessment. These shortcomings are expected to be overcome by the new high spatial-resolution TerraSAR-X satellite that is obtaining reliable data for nearshore areas, being able to provide data at 2 - 3 day interval.
- Integrating Offshore Wind and Wave Resource AssessmentPublication . Pontes, M.T.; Sempreviva, A.M.; Barthelmie, R.; Giebel, G.; Costa, Paula Silva; Sood, A.The aim of this paper is to review the sources of wind and wave information, the methodologies to assess offshore wind and wave energy resources, and the more relevant results at the European level as a first step to integration of the evaluation of both resources. In situ and remote sensed wind and wave data (using satellite based sensors) are done generally by distinct systems (except for SAR) but numerical atmospheric models and wind - wave models are closely related. Offshore wind resource studies using various types of data are reviewed especially in northern European seas and in the Mediterranean. The wave energy resource assessment at European and national levels is also reviewed and the various atlases are identified.
- Spectral Bandwidth and WEC Performance AssessmentPublication . Saulnier, J.-B.; Ricci, P.; Pontes, M.T.; Falcão, António F. de O.This paper investigates the dependency of wave energy conversion on the spectral bandwidth of sea-states. To this aim, the performance of an axisymmetrical Wave Energy Converter is assessed in the frequency domain by using a stochastic model in two far different wave climates (Portugal and North Sea) both represented by more than 23000 energy spectral densities obtained from measurements. The correlation between the performance and various bandwidth parameters found in the literature is observed. Then, refined methods for predicting the long-term converted wave energy based on wave statistics including spectral bandwidth are compared to more common procedures and conclusions are drawn.
- Wave energy resource in the North SeaPublication . Beels, C.; Henriques, J.C.C.; De Rouck, J.; Pontes, M.T.; De Backer, G.; Verhaeghe, H.Due to the high potential of wave energy and the goal to raise the share of renewable energy supply in the EU up till 20 % in 2020, the development of wave energy is accelerated. Until now the wave energy resource was highlighted in regions with a high wave energy density. As Wave Energy Converters (WECs) still contend with problems such as structural strength and mooring in a severe and energetic wave climate, the prospects of wave power conversion in a less aggressive wave climate should be investigated. This paper describes the wave power resource in a rather sheltered area i.e., the North Sea. The available wave power is studied on 34 locations. Characteristic sea states are defined for the Belgian, Dutch, German, Danish, Norwegian and UK Continental Shelf. An inverse-ray refraction model, implemented at INETI (Instituto Nacional de Engenharia, Tecnologia e Inovação), is presented to calculate the resource on more convenient locations for wave energy conversion. The wave power potential in the North Sea is compared with the resource of the West European coast. Near shore (< 30 km off the coast) up to a maximum of approximately 11 kW/m is available in the North Sea.