Feasibility of blue energy production using reverse electrodialysis In KwaZulu-Natal coastal region : modelling study using Comsol multiphysics

Abstract

Renewable energies have gained an increasing focus in recent years, due to the climate crisis contributed or associated with the current energy generation sources in South Africa. Thus, in this thesis, a renewable energy source called salinity gradient energy or blue energy will be presented and studied. The main objectives outlined in this dissertation were to evaluate the theoretical potential of electric energy production from the KwaZulu Natal rivers which are uThukela, uMvoti, uMkhomazi, Amanzimtoti, Umgeni, and uMfolozi. Finally, to optimize and simulate RED membrane and design reverse electrodialysis membranes and feeding pumps. In terms of the theoretical potential for producing electricity in the studied estuaries, it was concluded that the uThukela estuary has a considerably higher potential than the others. So, by this information, the possibility of designing the pilot plant in this estuary was studied, noting that the location of the pilot plant where the energy produced is greater and the capital cost are lower is at the mouth of the uThukela river. As for the pilot plant of RED, it was concluded that it is economically viable since the profit/loss found was R0 which is a break-even point, the plant is not generating a profit, but it’s also not generating a loss and since the focus for now is to try generating power. It’s economically viable in the sense that it covers its costs, but it is not profitable in terms of generating surplus revenue. It was concluded that using cheap and very thin membranes with high fluxes can increase the performance of the reverse electrodialysis. Also, the performance can be increased by using more than two reverse electrodialysis stacks instead of one.