1 / 22

Forecasting Offshore Wind Power in Portugal

Ana Rosa Trancoso ( arosa@ist.utl.pt ) Guillaume Riflet Prof. José Delgado Domingos. Forecasting Offshore Wind Power in Portugal. http://meteo.ist.utl.pt. Outline. Portugal Offshore Wind Power Offshore Forecasting Objective Case Study Methodology Results Conclusions

laksha
Download Presentation

Forecasting Offshore Wind Power in Portugal

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ana Rosa Trancoso (arosa@ist.utl.pt) Guillaume Riflet Prof. José Delgado Domingos Forecasting Offshore Wind Power in Portugal http://meteo.ist.utl.pt

  2. Outline • Portugal Offshore Wind Power • Offshore Forecasting • Objective • Case Study • Methodology • Results • Conclusions • Future Developments 15-09-2009 EOW Stockholm

  3. Portugal Offshore Wind Power Current Situation • Large continental platform (~25 to 200m depth) • Low slopes (~3%) • Potential 3.5 GW up to 40m depth* • 500 MW already being planned by TSO up to 2014. -200 * Source: Ana Estanqueiro, Director of Wind and Oceans Energy Unit, INETI. 15-09-2009 EOW Stockholm

  4. Offshore Forecasting: The Problem(vs Onshore) 15-09-2009 EOW Stockholm

  5. Offshore Forecasting: State of the art • Extrapolation based on Monin-Obukhov similarity theory is not adequate above 50 m over sea. • Sea surface roughness has minor impact. • Thermal effects (air-sea temperature gradients and thermal winds such as sea breeze) are being recognized as non negligible. (Lange, 2002, Sempreviva et al., 2007) 15-09-2009 EOW Stockholm

  6. Objective • Upwelling is a phenomena where cold deep waters rise to the surface and decrease Sea Surface Temperature (SST) • It’s frequent and intense in Portugal, from April to September, stronger in August. What is the influence of this phenomena in offshore wind power forecasts? 15-09-2009 EOW Stockholm

  7. Case Study: August 2008 1 Aug 2008 10 Aug 2008 Synoptic Situation by GFS Reanalysis Colour: 500 hPa geopotential (gpdm) White contours: Pressure at surface (hPa) Source: http://www.wetterzentrale.de 20 Aug 2008 30 Aug 2008 15-09-2009 EOW Stockholm

  8. Case Study: Sea Surface Temperature • ODYSSEA (Ocean Data Analysis System) • L4 product (multi-sensor merged high-resolution) • 0.02° (~2km) • Daily images • Since Oct 2007 • Online! 26 Aug 2008 12:00 15-09-2009 EOW Stockholm

  9. Methodology: WRF WRF Terrain (9km) Simulation Conditions 88x54x27 • WRF-ARW v3.011: • Microphysics: 3-class WRF • Radiation: RRTM • Land Surface Model: Noah • PBL: Yonsé Univ. • Cumulus: Kain-Fritsch • Boundary: Analysis from GFS grib2 (0.5⁰) 15-09-2009 EOW Stockholm

  10. Methodology: Twin Experiment GFS (0.5⁰ ~ 40 km) ODYSSEA (0.02⁰ ~ 2 km) 6 Aug 2008 12:00 15-09-2009 EOW Stockholm

  11. Results: Mean Wind Speed August 2008 Mean Wind Speed = +0.6 H=80 m H=100 m H=120 m 0 -0.6 15-09-2009 EOW Stockholm

  12. Wind Speed @80m 12 Mean wind speed +0.6 6 Mean difference 0 0 4 St. dev. wind speed -0.6 3 2 1 15-09-2009 EOW Stockholm

  13. Converting to Power • What is the importance of this difference for forecasting on 500 MW offshore? *Lange, 2005 15-09-2009 EOW Stockholm

  14. MeanDifferences +0.3 +0.3 Wind speed Vorticity 0 0 August 2008 @ 80m -0.7 -0.6 +0.4 +0.8 zonal meridional 0 0 -0.6 -0.3 15-09-2009 EOW Stockholm

  15. Stability: Viana Castelo Height (m) Potential Temp. (ºC) 9 km Land Sea 11 Aug2008 0 h + 6 h 12 h 18 h 24 h GFS ODYSSEA 15-09-2009 EOW Stockholm

  16. Stability: Aveiro Height (m) Potential Temp. (ºC) 9 km Land Sea 11 Aug2008 0 h + 6 h 12 h 18 h 24 h GFS ODYSSEA 15-09-2009 EOW Stockholm

  17. Stability: Figueira da Foz Height (m) Potential Temp. (ºC) 9 km Land Sea 11 Aug2008 0 h 6 h + 12 h 18 h 24 h GFS ODYSSEA 15-09-2009 EOW Stockholm

  18. Stability: Torres Vedras Height (m) Potential Temp. (ºC) 9 km Land Sea 11 Aug2008 0 h 6 h + 12 h 18 h 24 h GFS ODYSSEA 15-09-2009 EOW Stockholm

  19. Conclusions • Offshore wind forecasting presents different challenges than onshore • Twin experiment indicates: • positive feedback in winds, e.g., decrease in SST causes a decrease nearshore northerly wind speed. • Increase stability on and offshore, up to 200m. • Seems to decrease transversal sea breeze. • Offshore wind resource assessment and forecasts should take into account sea interaction, otherwise optimistic. 15-09-2009 EOW Stockholm

  20. Future Developments • 2-way coupling with ocean to identify positive & negative feedbacks in air-sea interaction. • Validation with buoys and satellites. • Best resolution compromise. 15-09-2009 EOW Stockholm

  21. References • Mizzi, A. P., Pielke, R. A. (1984) A Numerical Study of the Mesoscale Atmospheric Circulation Observed during a Coastal Upwelling Event on 23 August 1972. Part I: Sensitivity Studies. J. Climate, 76:76-90. • Lange, B. (2002) Modelling the Marine Boundary Layer for Offshore Wind Power Utilization. PhD Thesis, Physics Faculty, Oldenburg University. • Lange, M. (2005) On the uncertainty of Wind Power Predictions - Analysis of the Forecast Accuracy and Statistical Distribution of Errors. J. of Solar Eng., 127:177-184. • Sempreviva, A. M., Barthelmie, R., Giebel, G., Lange, B., Sood, A. (2007) Offshore wind resource assessment in European Seas, state-of-the-art. A surveu within the FP6 “POW’OW” Coordination Action Project. EWEC Milan, Italy. • Song, Q. Chelton, D. B., Esbensen, S. K., Thum, N., O’Neill, L. (2009) Coupling Between Sea Surface Temperature and Low-Level Winds in Mesoscale Numerical Models. J. Climate. 22:146-164. 15-09-2009 EOW Stockholm

  22. Thank you! arosa@ist.utl.pt http://meteo.ist.utl.pt/new http://rosatrancoso.googlepages.com 15-09-2009 EOW Stockholm

More Related