2.1.1. Anemometers and ERA5

The university building of Eibar (Engineering School of Gipuzkoa) was selected (longitude: 2.946◦ W; latitude: 43.258◦ N) to demonstrate a method for formulating a preliminary estimation of energy production using quantile-matching calibration versus a cup anemometer installed on the roof. Figure 1 shows a satellite view of the engineering school and the position of two anemometers installed on two buildings. After eight months of data acquisition, Anemometer 1 showed the best correlations with the ERA5 reanalysis, and its dataset was used for the calibration and energy estimation procedure.

The ERA5 reanalysis, ECMWF's most recent atmospheric reanalysis, covers the second half of the 20th century and this century [23]. For this study and the calibration, 40 years of data were used (from 1979 to 2018), because the complete reanalysis is not ye<sup>t</sup> available. The correlation between ERA5 and the anemometers was computed within their period of intersection (from June 2018 to February 2019). These data include atmospheric and oceanic variables, and are an appropriate tool for estimating wind energy potential [24] offshore and onshore. In this study, ERA5 hourly data with a resolution of 0.3◦ × 0.3◦ was used.

**Figure 1.** Selected buildings and anemometers 1 and 2 on the roof.
