Performance evaluation of solar Photovoltaic systems: a case of fixed, single and dual axis tracking systems

Abstract

Solar energy is a clean and naturally available source of energy. Its exploitation has been hampered by the low conversion efficiency of PV panels. This research investigates the technical and economic benefits of two modes solar tracking systems that is, single axis and dual axis tracking systems. The additional energy achieved by solar tracking is compared to energy harnessed from a solar PV operating in a fixed platform. The objective of this work is to quantify the benefits of solar tracking systems and give a verdict on its importance in the solar PV industry. Computer simulation of a 1 MW solar PV plant installed at latitude -1.3˚ and longitude 36.75˚ operating under three modes of operation was performed and it was discovered that dual axis is the most attractive in terms of energy yield and fixed axis mode was the least attractive in terms of energy yield. When the economic analysis was carried out using the Net Present Value approach, when the cost of land was wholly subsidized by the government then single axis tracking was the most economically viable followed by fixed axis and dual axis was the least economically viable. In absence of land subsidiesfixed axis became the most economically viable followed by single axis and dual axis was the least viable option. The maximum threshold in the cost of land per acre beyond which it is not economically viable to invest in the PV plant for this area of study is USD 190592, USD 91236 and USD 98170 respectively for single axis, fixed axis and dual axis tracking. It was concluded that full benefits of tracking could be realized in this area of study if the cost of land is subsidized and Balance of System (BOS) is low. Tracking is also beneficial when the irradiance level is high. In the area of study it was more beneficial to incorporate tracking in the months of December, January and February in relation to other months. From historical data, these are the hottest months in a typical meteorological year in Nairobi.