Incorporating shading losses in solar photovoltaic potential assessment at the municipal scale

• Published in: Solar energy Vol. 86; no. 5; pp. 1245 - 1260
• Main Authors: Nguyen, Ha T., Pearce, Joshua M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-05-2012; Elsevier; Pergamon Press Inc
• Subjects: Algorithms; Applied sciences; Connection and protection apparatus; Direct energy conversion and energy accumulation; Electric power; Electrical engineering. Electrical power engineering; Electrical power engineering; Electronics; Energy; Engineering Sciences; Equipments, installations and applications; Exact sciences and technology; GIS; Natural energy; Photoelectric conversion; Photovoltaic; Photovoltaic cells; Photovoltaic conversion; Renewable energy; Shading; Solar energy; Solar irradiation modeling; Solar radiation; Studies; Canada; North America; Ontario; America; Ontario Canada; GIS; Solar irradiation modeling; Shading; Photovoltaic; Renewable energy; Solar energy; Multicriteria analysis; Power system economics; Multiobjective programming; Modeling; Surface effect; Trade; Roof; Power markets; Robustness; Photovoltaic system; Gas insulated switchgear; System design; Algorithm; Mesoscale; Geographic information system; Morphology; Irradiation; Lidar; Shadowing; Spatial resolution
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2012.01.017

► We developed a solar irradiation model with terrain & near surface shadowing effects. ► It utilizes free and open source GRASS and the module r.sun in modeling irradiation. ► The workflow is validated on LiDAR data for 100 buildings. ► The trade off of each computation options has been quantified at the meso scale.
Recently several algorithms have been developed to calculate the solar photovoltaic (PV) potential on the basis of 2.5D raster data that can capture urban morphology. This study provides a new algorithm that (i) incorporates both terrain and near surface shadowing effects on the beam component; (ii) scales down the diffuse components of global irradiation; and (iii) utilizes free and open source GRASS and the module r.sun in modeling irradiation. This algorithm is semi-automatic and easy to upgrade or correct (no hand drawn areas), open source, detailed and provides rules of thumb for PV system design at the municipal level. The workflow is pilot tested on LiDAR data for 100 buildings in downtown Kingston, Ontario. Shading behavior was considered and suitable roof sections for solar PV installations selected using a multi-criteria objective. At sub-meter resolution and small time steps the effect of occlusion from near object was determined. Annual daily horizontal irradiation values were refined at 0.55m resolution and were shown to be lower than those obtained at 90m by 30%. The robustness of r.sun as capable of working with different levels of surface complexity has been confirmed. Finally, the trade off of each computation option (spatial resolution, time step and shading effect) has been quantified at the meso scale, to assist planners in developing the appropriate computation protocols for their regions.