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Renewable energy has become an essential component for the survival of human beings. This is because conventional energy supply is limited, nearing its limits, and or destroying our environment. The complete transition to renewable energy is a major approach to achieving sustainable and clean energy distribution progress in this ever-changing and demanding world. This research work investigates the knowledge of renewable energy among the youth and their understanding of sustainable energy prosperity towards meeting the future generation's energy needs. To achieve this, a set of questionnaires was developed to identify their knowledge of various renewable energy resources, energy aspects, applications, and the extent to which the current syllabus provides a well-developed background. They were administered to high school students in KwaZulu-Natal, Durban. The main findings of this investigation reveal that the students were most familiar with solar energy, which could be due to the increasing availability of solar panels across the nation. However, a lack of awareness and little understanding of geothermal energy was noted among the high school students. This indicates a poor future for its development. Furthermore, 86% of the students agreed that conventional energy sources would likely still be relied upon by a significant portion of the global population to meet daily energy needs. Therefore, the government must take swift action to address these issues, by promoting the deployment of renewable energy sources in schools.

Wind energy is a promising renewable energy source that can contribute to addressing the energy challenges faced by countries such as Nigeria and South Africa. Wind turbine modeling has emerged as a critical tool for optimizing the design, operation, and maintenance of wind turbines, as well as for integrating wind energy into the power grid. This approach can potentially enhance the performance and reliability of wind turbines, increase their energy production, and reduce their environmental impact. The review examines various wind turbine modeling approaches and techniques. It also discusses these modeling approaches' strengths and limitations and highlights their potential applications in addressing energy challenges in Nigeria and South Africa. Overall, this comprehensive review provides valuable insights into the potential for wind turbine modeling to address energy challenges in Nigeria and South Africa. It provided a thorough analysis of the current state of wind turbine modeling technology and highlighted areas for further research and development.

The urgent and indispensable need to develop new methods of enhancing heat transfer efficiency to improve energy devices’ performance cannot be overlooked in this era of green energy and sustainable technologies. Nanofluids research has proliferated in the past decade, and reports indicate that nanofluids can be used for heat transfer applications in engineering and in general and/or commercial industries. Nanofluid is the dispersion of nanoparticles with high thermal conductivity in common working fluids. Nevertheless, a growing area of research in recent years has involved using two or more nanoparticles in a base fluid, known as hybrid nanofluids. Studies showed that hybrid nanofluids exhibited better thermal and rheological characteristics than mono nanofluids. In addition, many researchers have reported on the thermal-fluid behaviours of nanofluids in comparison with hybrid nanofluids on natural convection in cavity flows. This review discusses hybrid nanofluids preparation, stability analysis and characterization, thermal properties, and heat transfer characteristics in cavities. Furthermore, hybrid nanofluids demonstrated better heat transfer characteristics than mono nanofluids or conventional fluids even as more research is needed in terms of hybrid nanofluids preparation, stability, characterization, and applications.

The heating and cooling of fluid play a crucial role in many industries, such as transportation, electronics, and manufacturing; however, among other concerns like size, weight, and cost reduction of cooling and heating systems, heat transfer enhancement is a primary concern in many industrial applications. As a result, a large number of researchers have carried out numerous studies to find alternatives to enhance heat transfer. The research on nanofluids has proliferated in the past decade, and reports indicate that nanofluids can be used for heat transfer applications in engineering and in general and/or commercial industries. Nevertheless, a growing area of research in recent years has involved employing more than one type of nanoparticles in a base fluid, known as hybrid nanofluids. Studies showed that hybrid nanofluids exhibited improved rheological and thermal characteristics than single nanoparticle nanofluids. In this study, the natural convection of alumina – multiwalled carbon nanotube /water hybrid nanofluid formulated using a two-step technique at a percentage weight ratio of 10:90 Al2O3: MWNCT at various nanoparticles volume concentrations of 0.00, 0.05, 0.10, 0.15, and 0.20 vol% was studied inside a square cavity with two vertical walls which are isothermal, aimed at the Rayleigh number (Ra) range of 2.81 × 108 to 8.58 × 108 . The average Nusselt number (Nuav), heat transfer coefficient (hav), heat transfer (Qav), and Rayleigh number (Ra) were considered at varying temperature gradients of 20 °C – 50 °C. Al2O3- MWCNT/water hybrid nanofluid with 0.10 vol% volume concentration was discovered to have the maximum value for hav, Qav, and Nuav. However, it was also observed that a further increase in the hybrid nanoparticles' volume concentration led to their deterioration at various temperature gradients. The maximum enhancements of 43.98%, 49.27%, and 42.20% were noted for hav, Qav, and Nuav, respectively, at ∆T = 50 °C, in comparison with the base fluid. Al2O3-MWCNT/water hybrid nanofluid application in a square cavity demonstrated enhanced free convection. Several results from this study indicate that hybrid nanofluids offer an advantage over mono-particle nanofluids and base fluids.