Validation of spatially resolved all sky imager derived DNI nowcasts

Pascal Kuhn (1) , Stefan Wilbert (1) , David Schüler (1) , Christoph Prahl (1) , Thomas Haase (1) , Lourdes Ramírez (2) , Luis Zarzalejo (2) , Angela Meyer (3) , Laurent Vuilleumier (3) , Philippe Blanc (4) , Jean Dubranna (4) , Andreas Kazantzidis (5) , Marion Schroedter-Homscheidt (1) , Tobias Hirsch (1) , Robert Pitz-Paal (1)

1 DLR - German Aerospace Center
2 CIEMAT - Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
3 Federal Office of Meteorology and Climatology MeteoSwiss
4 O.I.E. - Centre Observation, Impacts, Énergie
5 University of Patras

Mainly due to clouds, Direct Normal Irradiance (DNI) displays short-term local variabilities affecting the efficiency of concentrating solar power (CSP) plants. To enable efficient plant operation, DNI nowcasts in high spatial and temporal resolutions for 15 to 30 minutes ahead are required. Ground-based All Sky Imagers (ASI) can be used to detect, track and predict 3D positions of clouds possibly shading the plant. The accuracy and reliability of these ASI-derived DNI nowcasts must be known to allow its application in solar power plants. Within the framework of the European project DNICast, an ASI-based nowcasting system was developed and implemented at the Plataforma Solar de Almería (PSA). Its validation methodology and validation results are presented in this work. The nowcasting system outperforms persistence forecasts for volatile irradiance situations.

Mots clés: Solar power; Direct Normal Irradiance

Pascal Kuhn, Stefan Wilbert, David Schüler, Christoph Prahl, Thomas Haase, et al.. Validation of spatially resolved all sky imager derived DNI nowcasts. AIP Conference Proceedings, 2017, SOLARPACES 2016: International Conference on Concentrating Solar Power and Chemical Energy Systems, 1850 (1), pp.140014. ⟨10.1063/1.4984522⟩. ⟨hal-01553607⟩