Study of the temporal variation of offshore wind energy potential in southeast Brazil

Abstract

Global energy consumption has grown over the years marked by technological development and industrialization. Renewable sources have gained prominence due to climate urgency and international agreements that aim to reduce CO2 emissions across the planet. In this regard, wind energy, already consolidated in the onshore region, has evolved offshore regions. In Brazil, there is a growing interest in offshore wind projects. Many of these projects are currently through the environmental licensing process, mostly in the southeastern region of the country. It is known that this area has a relevant wind energy potential. This area is dynamically dominated by the South Atlantic Subtropical Height, the main meteorological phenomenon in the region, which has been affected by recent changes in the global atmospheric circulation. This work aims to evaluate the temporal variation of offshore wind potential in southeastern Brazil. ERA5 reanalysis hourly outputs from 1979 to 2020 were evaluated through high-level computational tools (python and CDO programming languages and GIS software) and consolidated statistical analysis mechanisms. A general decrease in the frequency of low wind speed records (≤7.5 m·s−1) and a raise in the higher wind speed range (>7.5 m·s−1), mainly related to the intensification and expansion of the South Atlantic Subtropical Height (SASH) over the past 40 years, were observed and affected the estimates of offshore wind potential over the analyzed region. Apart from the coast of São Paulo and the south coast of Rio de Janeiro, there was a consistent increase in the wind power density over decades. The four analyzed points presented an increase of 1.55 W·m−2·y−1 to 1.89 W·m−2·y−1, which corresponds to an increase of 8.2% to 11.2% in the median wind power density.