4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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    Estimating rooftop solar energy potential using spatial radiation models and thermal remote sensing: The case of Witwatersrand University
    (University of the Witwatersrand, Johannesburg, 2023) Ndemera, Rudo Hilda; Adem, Ali K.; Adam, Elhadi
    The main purpose of this research was to estimate the University of Witwatersrand building’s rooftop solar energy potential using the GIS-based solar Area Solar Radiation (ASR) analyst upward hemispherical view shed algorithm. The two major datasets used in this research for rooftop solar energy potential modelling are building footprint data and the Digital Surface Model. Building footprint data, specifically rooftop area was extracted using machine learning CNTK unified toolkit and deep neural networks. The data was presented as individual polygon shape files for each building. The high-resolution Digital Surface Model imagery was sourced from the Advanced Land Observation Satellite. Pre-processing of the imagery was done for atmospheric correction. The DSM was then used in the Area Solar Radiation model to create an upward view shed for every point on the study area which is essential for computing solar radiation maps. The efficiency of using this algorithm is that it considers the shading effects caused by surrounding topography and surrounding man-made features, alterations in the azimuth angle and the position of the sun. Apart from the incoming solar radiation reaching the rooftops, the elevation and orientation of the rooftop cells limit the solar panel tilt angle and intensity of the incoming solar radiation, respectively. These factors were used in setting the suitability criteria together with solar radiation for the identification of suitable rooftop cells in this research. The relationship between land surface temperature and solar radiation values was assessed to determine if it can be used as an indicator for solar panel efficiency. Results from this research indicate that the University of Witwatersrand receives high levels of incoming solar radiation and has a high solar energy rooftop generation capacity that can meet the energy demand on campus. To improve accuracy of the research results, a drone could have been used to measure insolation across the study area to improve the spatial resolution. However, this was not possible due to various restrictions.
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    Impact of weighted average cost of capital (wacc) on utility‐scale solar photovoltaics (pv) levelized cost of electricity
    (University of the Witwatersrand, Johannesburg, 2023) Shendile, Severus Twahafa; Odei-Mensah, Jones
    Namibia has one of the highest solar irradiation levels in the world, making it an ideal destination for renewable energy investments. The country receives an average of 300 days of sunshine per year. This means that there is an abundance of solar energy that can be harnessed for electricity generation using solar photovoltaic (PV) technology. The levelized cost of electricity (LCOE) is a key metric used to evaluate the financial viability of a solar PV project and is influenced by a range of factors that impact the cost of generating electricity from solar energy. The parameters that affect LCOE for solar PV systems include solar irradiation, O&M cost, financing cost, inverter efficiency, system design, system lifetime, regulatory environment, and the weighted average cost of capital. These parameters can interact with each other, and changes to one parameter can impact the LCOE in different ways. Several studies have considered the sun’s strength as the primary exogenous factor driving the cost of electricity and have treated other parameters such as the WACC, as largely endogenous and thus irrelevant to their analysis. This study has analyzed how the weighted average cost of capital from twenty- six projects in Namibia between 2014 -2022, impacts the levelized cost of electricity of utility-scale photovoltaic. This study has shown that while both solar irradiation and the WACC are essential factors that influence the LCOE of a solar PV project, WACC has a more significant impact on the LCOE for solar PV projects than solar irradiation because the cost of capital represents a substantial portion of the total cost of a solar PV project, while solar irradiation mainly affects the electricity generation potential of the project