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Nowcasting of DNI Maps for the Solar Field Based on Voxel Carving and Individual 3D Cloud Objects from All Sky Images

Nouri, Bijan and Kuhn, Pascal Moritz and Wilbert, Stefan and Prahl, Christoph and Pitz-Paal, Robert and Blanc, Philippe and Schmidt, Thomas and Yasser, Zeyad and Ramirez, Lourdes and Heinemann, Detlev (2018) Nowcasting of DNI Maps for the Solar Field Based on Voxel Carving and Individual 3D Cloud Objects from All Sky Images. In: AIP Conference Proceedings, 2033 (190001). SolarPACES Conference, 26.-29. Sept. 2017, Santiago de Chile. DOI: 10.1063/1.5067196

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Official URL: https://aip.scitation.org/doi/10.1063/1.5067196

Abstract

Accurate nowcasts of the direct normal irradiance (DNI) for the next 15 min ahead can enhance the Overall efficiency of concentrating solar power (CSP) plants. Such predictions can be derived from ground based all sky imagers (ASI). The main challenge for existing ASI based nowcasting systems is to provide spatially distributed solar irradiance information for the near future, which considers clouds with varying optical properties distributed over multiple heights. In this work, a novel object oriented approach with four spatially distributed ASIs is presented. One major novelty of the system is the application of an individual 3D model of each detected cloud as a cloud object with distinct attributes (height, position, surface area, volume, transmittance, motion vector etc.). Frequent but complex multilayer cloud movements are taken into account by tracking each cloud object separately. An extended validation period at the Plataforma Solar de Almería (PSA) on 30 days showing diverse weather conditions resulted in an average relative mean absolute error (relMAE) of around 15 % for a medium lead time of 7.5 minutes and a temporal average of 15 minutes. Further reductions of the relMAE were achieved by spatial aggregation, with a relMAE of 10.7 % for a lead time of 7.5 minutes, a field size of 4 km² and a temporal average of 1 minute (during one day). Nowcasting systems described in the literature reach similar deviations but were often validated only for a few days based on a single ground measurement station, which confirms the good performance and the high applicability of the presented system. Three implementations of the system exist already demonstrating the market maturity of the system.

Item URL in elib:https://elib.dlr.de/115635/
Document Type:Conference or Workshop Item (Speech)
Title:Nowcasting of DNI Maps for the Solar Field Based on Voxel Carving and Individual 3D Cloud Objects from All Sky Images
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Nouri, BijanBijan.Nouri (at) dlr.deUNSPECIFIED
Kuhn, Pascal MoritzPascal.Kuhn (at) dlr.dehttps://orcid.org/0000-0001-9978-5706
Wilbert, StefanStefan.Wilbert (at) dlr.dehttps://orcid.org/0000-0003-3573-3004
Prahl, Christophchristoph.prahl (at) dlr.dehttps://orcid.org/0000-0002-8596-9050
Pitz-Paal, RobertRobert.Pitz-Paal (at) dlr.dehttps://orcid.org/0000-0002-3542-3391
Blanc, Philippemines paristechUNSPECIFIED
Schmidt, Thomast.schmidt (at) dlr.deUNSPECIFIED
Yasser, Zeyadtsk-flagsol gmbhUNSPECIFIED
Ramirez, LourdesciematUNSPECIFIED
Heinemann, Detlevuniversität oldenburgUNSPECIFIED
Date:8 November 2018
Journal or Publication Title:AIP Conference Proceedings
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
Volume:2033
DOI :10.1063/1.5067196
Status:Published
Keywords:Nowcasting, All sky imagers, Forecasting, Cloud cameras, cloud object
Event Title:SolarPACES Conference
Event Location:Santiago de Chile
Event Type:international Conference
Event Dates:26.-29. Sept. 2017
Organizer:SolarPACES
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
Location: Köln-Porz
Institutes and Institutions:Institute of Solar Research > Qualification
Deposited By: Kruschinski, Anja
Deposited On:20 Nov 2017 14:07
Last Modified:08 Nov 2019 03:00

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