Determining the Likely Tracking Choices for Utility Scale Photovoltaic Power Plants

Abstract

During long-term generation capacity expansion planning, generalised solar photovoltaic (PV) power generation profiles are used to represent expected future production. These profiles should ideally capture the varying solar resource characteristics across the region under consideration, as well as account for likely future PV technology choices (e.g. singleversus bi-facial) and orientation decisions (e.g. single-axis versus dual-axis tracking versus fixed). This paper investigates the hypothesis that the PV power generation profile used in South Africa”s recent long-term planning simulations does not accurately represent the current and expected future PV power generation in the country. The hypothesis is tested through a literature review and industry interviews aimed at determining the cost drivers and financial viability of various technology and orientation scenarios in South Africa's future generation capacity, ultimately informing the expected future contribution of PV and the expected representative power profile for current and future PV plants. The results highlight a significant disparity between the predominant use of fixed-tilt orientation systems in recent long-term planning, and the shift towards tracking solutions as indicated by this research. The techno-economic simulations clearly demonstrated monofacial (rather than bi-facial) single-axis tracking as the most cost-effective solution, with fixed-tilt solutions not optimal in any of the scenarios simulated. The paper contributes by showing that the current PV power profile used in South Africa”s long-term planning is not representative of the actual current and future PV technology and orientation choices. A second contribution is the establishment of a new profile that does represent these current and likely future choices. These results will be valuable to modellers and planners active in planning South Africa”s future power system.