On the influence of wind speed model resolution on the global technical wind energy potential

Previous estimations of the global technical onshore wind energy potential (WEP) range between 64 and 690 PWh/yr. The diversity of WEP estimates is caused by various applied wind resource data sets, geographical restrictions, and wind turbine features. So far, little attention was paid to the wind speed model resolution and hub height influence on national and global WEP. Thus, this study's goals were to compare WEP estimates from highly and coarsely resolved wind speed data in 120 and 140 m hub height. The wind resource was assessed based on ERA5 wind speed time series at a horizontal resolution of 0.25° × 0.25° and L-moments from the highly resolved Global Wind Speed Model (GloWiSMo) available at 250 m × 250 m horizontal resolution. Theoretical distributions and a generic 3.3 MW wind turbine power curve were used to estimate the average annual energy yield at a 1000 m × 1000 m global grid. A total of twelve geographical restrictions were specified to exclude inaccessible areas from WEP estimations. Using highly resolved wind speed data at 120 m hub height, global WEP was estimated to be 404 PWh/yr. It decreases by 16.1% (339 PWh/yr) using ERA-5 wind speed data, whereas, at 140 m hub height, WEP increases by 11.8% (452 PWh/yr). The results presented highlight the relevance of spatial resolution of wind speed data for wind resource assessment from local to global scales.