Spatial complementary of offshore wind farm Iberian Peninsula sites based on COSMO-REA6 high-resolution reanalysis.

The energy transition is a fundamental endeavour in the way towards a zero-carbon future that will allow us to mitigate anthropogenic climate change. There are plans at a European Union level and, also at Iberian Peninsula (IP) one, to strongly increase the installed wind power capacity by 2030, with the aim by 2050 of making Europe the first climate-neutral continent. Onshore wind and solar photovoltaic are currently by far the main renewable technologies installed on the IP, receiving other potential dispatchable energy resources such as offshore wind less attention. This resource should also be considered due to its high energy potential and the increasing difficulty of finding suitable land for new onshore wind farms. Although some areas, such as the western IP, show high potential, there are important spatial constraints for the deployment of floating offshore wind towers, related to wind infrastructure technologies and legislative limits. Together, wind power generation is, by nature, complex, irregular and hard to be forecasted. Thus, increasing interconnections between regions can dampen the impact of wind variability on local wind power generation. An analysis of the spatial complementarity of the top potential floating offshore wind farm sites across IP is then proposed in this work. For this purpose, hourly wind fields from COSMO-REA6 very high resolution reanalysis (0.055º) in the 1995-2018 period were used to compute the wind capacity. The wind speed was vertically interpolated to the hub height of 105 meters of a reference turbine at each grid point between the levels 36-39 (approximately 35 to 178 meters) of the reanalysis by a cubic polynomial function using the least squares fit. Then, a total of 55 potential locations of Iberian commercial floating wind farm projects were manually collected, mainly from publicly available information. Of these, ten potential sites were chosen by applying a methodology that finds the combination of sites that minimizes the coefficient of variation of the aggregate wind power. The first results indicate that, in the period considered, it is more advantageous for the Iberian electricity system to build wind farms farther apart, giving priority to wind farm projects located in the northeast and northwest coastal corners of IP. Thus, as more distant sites are added, the coefficient of variation decreases more than the capacity factor. This behaviour varies slightly by season, with the variation decreasing the most in winter and the capacity factor decreasing the most in summer.