Optimising photovoltaic power generation and useable area by varying the solar module tilt

Abstract

This paper deals with the optimisation of solar photovoltaic (PV) modules’ tilt and area required and the resulting energy generated, in light of the present attractive PV system prices. This was achieved by comparing the optimum PV inclination and its resulting output with other settings. We also analyzed other issues that may be tied to the change of tilt angle (dust accumulation, maintenance and aesthetical requirements) and their influence on the energy generated. Results showed that for a given area, an angle of around 15° for the PV modules would produce better overall energy output, when compared to the 30° tilt. The internal rate of return would also be better for this setup and this would positively affect the overall payback period of the PV installation. Dust accumulation would be a major factor in reducing power generation when the PV module inclination is lowered than 15°. PV modules placed on vertical facades would approximately produce the same total energy output as an inclined system for a given area, because the full area can be covered with the PV modules, while only 50% is utilised on a flat roof. However, the capital investment is also doubled and this increases the payback period. One could still consider the addition of PV modules on facades, because they can be used as building material and replace expensive glass facades or other finishing materials, which are normally specially coated and strengthened to reduce solar gains and withstand wind loading. The elimination of these other materials and associated cost-savings improves the payback period of such systems.