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

Abstract

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 semiautomatic 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 90 m 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.

Applications of 3D City Models: State of the Art Review

“…Figure 5 illustrates a visualisation of a shadow analysis. This use case is also essential in the estimation of the solar potential of buildings, which may negatively affect the photovoltaic yield of a solar panel [102,112,[222][223][224][225][226][227]. In this context, this use case is closely related to the previously mentioned one of estimating the insolation of buildings, and they are often used together.…”

Automatic Sky View Factor Estimation from Street View Photographs—A Big Data Approach

“…A significant relationship was found between SVF and urban heat islands at a local scale [9]. Sky obstruction can substantially reduce the amount of solar radiation reaching the ground [10], and hence SVF serves an important role in solar radiation modeling [11,12]. It was found that SVF was significantly correlated with surface emissivity in urban canyons [13].…”

Photovoltaic potential assessment and ranking of rooftops segments based on LiDAR data

“…State-of-the-art methods also consider shadowing from vegetation by either using semitransparent vegetation modelling [6] or light transmission estimation by using satellite-derived Leaf Area Index (LAI) [10]. Most of the state-of-the-art also consider only the constant efficiency of a PV module when estimating the PV potential [8]. Recently, it has been shown that it has bias in accuracy, in comparison to using the nonlinear efficiency characteristics of a PV module and a solar inverter [10].…”