Offshore Validation of ERA5 Reanalysis with Hub Height Wind Observations of Brazil

Abstract

Wind is a natural resource that has been explored widely in recent years in different regions around the world. In Brazil, the penetration of wind energy represents ~ 11 % of the country's generation capacity, currently explored in continental areas. Although offshore wind projects are in the environmental licensing phase, the country lacks coastal and offshore observations performed at height of modern wind turbines. Atmospheric models have been a valuable tool for the assessing the potential and distribution of offshore wind power. Some reanalysis present hourly datasets with long time record and global coverage. Here the ERA5 atmospheric reanalysis of ECMWF is compared to hub height wind observations of three locations in Brazil. The first is derived from a coastal meteorological tower located on Alcantara Launch Center in the state of Maranhão (MA- Tower). The second is derived from LIDAR observations of a coastal pier in Santa Catarina (SC-LIDAR). The last are tall tower observations performed by a Petrobras oil platform located in Santos Basin (Tower-PETRO). The temporal characteristics of the winds at these locations are explored and compared to ERA5. Power generation is simulated considering a 8 MW offshore wind turbine. Results demonstrate that ERA5 is well suited for daily to monthly scale analysis of wind speeds. The model spatial resolution, however, precludes a close representation of the diurnal variability in locations where the sea breeze is an important component of the circulation. Power simulations demonstrated good results for all ERA5 comparisons.