Impacts of extreme land-use change on wind profiles and wind energy according to regional climate models  

Humans change the climate in many ways, for example, by emitting greenhouse gases or by changing land-use. While studies typically investigate the joint effects of human activity, we here isolate the impact of afforestation and deforestation on winds in the lowermost 350 m of the atmosphere to better understand the role of forests in large-scale wind energy assessments. We use vertically resolved sub-daily output from two regional climate models and compare two extreme scenarios from the LUCAS simulations (Davin et al., 2020). Our results show that afforestation lowers wind speeds by more than 1 m/s in many locations across Europe even 300 m above ground and thus matters at wind turbine hub heights. While adapting the parameters in standard extrapolation allows to capture long-term mean winds well, it remains insufficient to compute wind energy potentials as it fails to capture essential spatio-temporal details, such as changes in the daily cycle. We therefore follow an alternative approach that leverages the vertical resolution of the regional climate models to account for wind profile complexity. Doing so, we report strong changes in wind energy capacity factors due to afforestation and deforestation: they change by up to 50 % in relative terms. Our results confirm earlier studies that land use change impacts on wind energy can be severe and that they are generally misrepresented with common extrapolation techniques.   References: Davin, E. L., Rechid, D., Breil, M., Cardoso, R. M., Coppola, E., Hoffmann, P., Jach, L. L., Katragkou, E., de Noblet-Ducoudré, N., Radtke, K., Raffa, M., Soares, P. M. M., Sofiadis, G., Strada, S., Strandberg, G., Tölle, M. H., Warrach-Sagi, K., and Wulfmeyer, V: Biogeophysical impacts of forestation in Europe: First results from the LUCAS Regional Climate Model intercomparison, Earth Syst. Dynam., 11, 183–200, 2020, https://doi.org/10.5194/esd-11-183-2020, 2020 Preprint: Wohland, J., Hoffmann, P., Lima, D. C. A., Breil, M., Asselin, O., and Rechid, D.: Extrapolation is not enough: Impacts of extreme land-use change on wind profiles and wind energy according to regional climate models, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-2533, 2023