Assessment of solar potential of building roof surfaces at Makerere University Main Campus.

Abstract

Building-integrated photovoltaic generators are steadily attracting interest from numerous individuals and institutions in Kampala and other urban areas in Uganda. However, oftentimes there is insufficient information and spatial data available for assessing the solar potential and performance of various buildings. This limits the realization of optimum performance of installed photovoltaic solar panels. The purpose of this study was, therefore, to identify roof surfaces in Makerere University regarding their solar potential and suitability for the installation of rooftop PV solar systems. Using Analytical Hierarchy Process (AHP), the study investigated the suitability of building rooftops considering factors like aspect, slope, shading from surrounding topography, and the daily incident amount of global solar radiation computed using the ArcGIS Area Solar Radiation (ASR) tool. A suitability index map was generated followed by estimation of potential solar power output from most suitable roof surfaces. This yielded a total most suitable area of 54582.928 m2 with an estimated power output of 10.515 MW. The suitability index map was overlaid with a high-resolution aerial image for areas with pre-installed panels to compare the rendered map output with the ground truth. Most solar panels were found to lie in the moderate and most suitable roof surfaces zone. Computed global solar radiation was compared with daily observations obtained from the Center for Renewable Energy and Energy Conservation weather station. The comparison yielded an RMSE of 0.208, a moderate correlation coefficient of 0.492 and MBE of -0.078 hence the results of this study can be used as a guiding tool for prioritizing building rooftops for solar panel installation within Makerere.