Impact of Solar Panel Orientation on Large Scale Rooftop Solar Photovoltaic Scenario for Mumbai

Abstract

Abstract Application of solar photovoltaic systems at a large scale is becoming increasingly interesting for researchers, policymakers and investors. Singh and Banerjee (2015) [1] have presented a methodology for estimation of the rooftop solar photovoltaic potential of a city. The methodology has been applied and illustrated for the Indian city of Mumbai (18.980N, 72.830E). In this paper, different orientations of the solar panels to be used for the Mumbai rooftop solar photovoltaic scenario have been analyzed and compared in terms of their impact on the generation from the scenario. The three possible orientations studied and compared in this study are – fixed tilt orientation, two-point system orientation, and horizontal N-S axis E-W tracking. The results show that for the fixed tilt orientation, the best tilt angle for year-round optimal performance is same as the latitude of the place, i.e. 190. However, optimization of seasonal output would warrant another tilt angle. Further, it has been found that, as compared to the fixed tilt at 190, the two-point system gives 2.21% higher annual plane-of-array insolation; and horizontal N-S axis E-W tracking gives 10.18% higher annual plane-of-array insolation. However, in terms of the annual generation from the large scale Mumbai rooftop scenario, the gain is only 1.97% with the two-point system, and 9.62% with the horizontal N-S axis E-W tracking, as compared to the fixed tilt (at 190) orientation. Incremental cost-benefit analysis for the excess capital expenditure on the tracking equipment has also been done. For this analysis, the Average Unit Cost of Power Supply for India has been taken into account, which is found to have a CAGR of 8.57% over the last decade; discount rate has been estimated as per the Renewable Energy Tariff Regulations passed by the Central Electricity Regulatory Commission (CERC), and has been found to be 10.76%. The ensuing analysis gives a discounted payback period of around 13 years for the excess capital expenditure due to the tracking equipment costs.