Performance analysis of a grid-connected rooftop solar PV system in Kuala Terengganu, Malaysia

Abstract

This paper presents the real performance of a 7.8 kWp grid-connected rooftop photovoltaic (PV) system from a field monitoring at a residential house under the feed-in-tariff scheme. The performance parameters of PV system were assessed based on the two-year energy production in 2018–2019. PVsyst software was used to find the best orientation and tilt angle for the selected area to increase the system performance. Next, the PV derating factor was calculated from the two-day data collection. The derating factor was used in the simulation of the system using HOMER Pro, and the economic parameters for 21 years project lifetime were predicted. The results show that the performance of the installed system was better for 2019 compared to 2018 due to the higher solar irradiance in 2019 and the malfunction of inverter in July to August 2018. The best performance ratio obtained from the recorded data was 75.72% and the average loss was 1.68 kWh/kWp/day. The annual capacity factor and overall system efficiency were in the range of 13%–16% and 10%–12%, respectively. The best tilt angle and orientation was 5° with the increment of annual energy production up to 4.8%. From the simulation, the error between the simulation and measurement results was high when the derating factor was assumed to be 100%. When the value used was based on the calculation obtained from data collection, the annual error was 1.7%, which is acceptable. Thus, the software is considered reliable assuming no component failure in the PV system. From the economic analysis, the annual net profit can be obtained was almost RM 3,000, and the payback period was in the range of 5–7 years. In addition, the installed PV system on the single house has the potential to reduce the CO2 emission of approximately 7.45 tons/year.