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Validation of an all-sky imager-based nowcasting System for industrial PV plants

Kuhn, Pascal Moritz and Nouri, Bijan and Wilbert, Stefan and Prahl, Christoph and Kozonek, Nora and Schmidt, Thomas and Yasser, Zeyad and Ramirez, Lourdes and Zarzalejo, L.F. and Meyer, Angela and Vuilleumier, L. and Heinemann, Detlev and Blanc, Philippe and Pitz-Paal, Robert (2017) Validation of an all-sky imager-based nowcasting System for industrial PV plants. Progress in Photovoltaics: Research and Applications, pp. 1-14. Wiley. doi: 10.1002/pip.2968. ISSN 1062-7995.

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/pip.2968/full


Because of the cloud-induced variability of the solar resource, the growing contributions of photovoltaic plants to the overall power generation challenges the stability of electricity grids. To avoid blackouts, administrations started to define maximum negative ramp rates. Storages can be used to reduce the occurring ramps. Their required capacity, durability, and costs can be optimized by nowcasting systems. Nowcasting systems use the input of upward-facing cameras to predict future irradiances. Previously, many nowcasting systems were developed and validated. However, these validations did not consider aggregation effects, which are present in industrial-sized power plants. In this paper, we present the validation of nowcasted global horizontal irradiance (GHI) and direct normal irradiance maps derived from an example system consisting of 4 all-sky cameras (“WobaS-4cam”). The WobaS-4cam system is operational at 2 solar energy research centers and at a commercial 50-MW solar power plant. Besides its validation on 30 days, the working principle is briefly explained. The forecasting deviations are investigated with a focus on temporal and spatial aggregation effects. The validation found that spatial and temporal aggregations significantly improve forecast accuracies: Spatial aggregation reduces the relative root mean square error (GHI) from 30.9% (considering field sizes of 25 m2) to 23.5% (considering a field size of 4 km2) on a day with variable conditions for 1 minute averages and a lead time of 15 minutes. Over 30 days of validation, a relative root mean square error (GHI) of 20.4% for the next 15 minutes is observed at pixel basis (25 m2). Although the deviations of nowcasting systems strongly depend on the validation period and the specific weather conditions, the WobaS-4cam system is considered to be at least state of the art.

Item URL in elib:https://elib.dlr.de/115452/
Document Type:Article
Title:Validation of an all-sky imager-based nowcasting System for industrial PV plants
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Kuhn, Pascal MoritzUNSPECIFIEDhttps://orcid.org/0000-0001-9978-5706UNSPECIFIED
Nouri, BijanUNSPECIFIEDhttps://orcid.org/0000-0002-9891-1974UNSPECIFIED
Wilbert, StefanUNSPECIFIEDhttps://orcid.org/0000-0003-3573-3004UNSPECIFIED
Prahl, ChristophUNSPECIFIEDhttps://orcid.org/0000-0002-8596-9050UNSPECIFIED
Yasser, Zeyadtsk-flagsol gmbhUNSPECIFIEDUNSPECIFIED
Heinemann, Detlevuniversität oldenburgUNSPECIFIEDUNSPECIFIED
Blanc, Philippemines paristechUNSPECIFIEDUNSPECIFIED
Pitz-Paal, RobertUNSPECIFIEDhttps://orcid.org/0000-0002-3542-3391UNSPECIFIED
Date:November 2017
Journal or Publication Title:Progress in Photovoltaics: Research and Applications
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 1-14
Keywords:all‐sky imager, grid integration, nowcasting systems, photovoltaic, plant control, solar nowcasting
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Thermal Technology
DLR - Research area:Energy
DLR - Program:E SW - Solar and Wind Energy
DLR - Research theme (Project):E - Impact of Desert Environment (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Solar Research > Qualification
Deposited By: Kruschinski, Anja
Deposited On:21 Nov 2017 17:28
Last Modified:02 Nov 2023 13:06

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