Harnessing tidal energy for power generation in South Africa

Abstract

The growth of the world population has come with an increased demand for energy since every process requires it. The most widely used source of energy for generating electricity is coal, which contributes about forty percent. However, there is a global concern about climate change, of which the use of coal- and petroleum-based fuels are stated as contributing factors. Resultantly, demand for cleaner, sustainable energy sources is on the rise. Research indicates that tidal energy is able to generate quite a significant amount of electricity. It is against this backdrop that the research presented in this thesis was undertaken, investigating the design and development of a tidal wave barrage system for South Africa. Hence, the objective of this work is to calculate, design and simulate a tidal barrage system considering the generation capacity and cost of the system. The design enabled the calculation of the potential generation of power, as well as the required size of the tidal barrage. The calculated results were used as input for the tidal wave barrage system model, which was used in the system simulation. The system functional diagram was used in developing a function Matlab®/Simulink® model, based on mathematical models of the constituent tidal barrage components. The input parameters for this model were derived from the tidal wave data and the mechanical design properties of the turbine and generator. The Simulink® simulations showed that the tidal barrage system could generate approximately 2MW per unit - the ideal generating capacity for which each generation unit was designed. However, the Simulink® simulations do not consider the hydrodynamics of the system. The hydrodynamics of the system were simulated using DTOcean® simulation software. The input for the simulation model was derived from the theoretical calculations, the tidal wave data, the site properties, and the Simulink® results. The simulations showed a lower power output compared with the Simulink® results. The system design was completed with the results indicating there is potential for generating power from tidal waves in South Africa. The economic value and costing of the tidal plant indicate that the levelised cost of energy is comparable to that of existing tidal power plants. This thesis will assist in paving the way for further studies into the utilisation of the country’s tidal energy, with a recommendation that data for specific sites is gathered for assessment of the power generation capacity.