Energy yield of solar PV in 34 Indonesian cities with respect to various roof pitches and orientations

In the tropical regions such as Indonesia, the energy yield difference from rooftop solar photovoltaic (PV) between facing to and away from the equator may be lesser than that in the non-tropical regions. However, a detailed recommendation on optimum roof orientation for various locations in Indonesia is yet to be found. This study aims to map the potential annual energy yield from rooftop solar photovoltaic (PV) in 34 Indonesian cities with respect to various roof pitches and orientations, and to quantify the impact of the design variables, using computational modelling and simulation with Rhinoceros, Grasshopper, and Ladybug plugins. The roof pitches as eight cardinal and inter-cardinal orientations of 20°, 30°, 45°, and 60° are considered as common roof pitches in Indonesia. Based on simulations of 100 Wp solar PV with 0.748 m² panel surface area, the greatest annual energy yield across all cities is approximately 208, 199, 183, and 158 kWh/m². The greatest annual energy yields are found in cities in Bali and Nusa Tenggara islands. The East orientation provides the maximum annual energy yield in most parts of Sumatera, Borneo, Sulawesi, and Papua islands. In almost all parts of Java, Bali, and Nusa Tenggara islands, the best orientation is North. Based on sensitivity analysis with multilinear regression, the roof pitch has a greater influence on the annual energy yield, compared to roof orientation. Selecting the optimum roof pitch is therefore critical in the design and implementation of rooftop solar PV in the Indonesian context.