Renewable energy choices and their water requirements in South Africa

Abstract

South Africa is an arid country, where water supply is often obtained from a distant source. There is increasing pressure on the limited water resources due to economic and population growth, with a concomitant increase in the energy requirement for water production. This problem will be exacerbated by the onset of climate change. Recently, there have been concerns about negative impacts arising from the exploitation of energy resources. In particular, the burning of fossil fuels is significantly contributing to climate change through the emission of carbon dioxide, a major greenhouse gas. In addition, fossil fuels are being depleted, and contributing to decreased energy security. As a result of this, the international community has initiated various interventions, including the transformation of policy and regulatory instruments, to promote sustainable energy. With this in mind, South Africa is making policy and regulatory shifts in line with international developments. Renewable energy is being promoted as one way of achieving sustainable energy provision in the country. However, some issues require scrutiny in order to understand the water footprint of renewable energy production. Due to the large gap that exists between water supply and demand, trade-offs in water allocation amongst different users are critical. In this vein, the main objective of this study was to investigate and review renewable energy choices and water requirements in South Africa. Data were acquired through a combination of a desktop study and expert interviews. Water withdrawal and consumption levels at a given stage of energy production were investigated. Most of the data was collected from secondary sources. Results show that there is limited data on all aspects of water usage in the production chain of energy, accounting in part for the significant variations in the values of water intensity that are reported in the literature. It is vital to take into account all aspects of the energy life cycle to enable isolation of stages where significant amounts of water are used. It is found that conventional fuels (nuclear and fossil fuels) withdraw significant quantities of water over the life-cycle of energy production, especially for thermoelectric power plants operated with a wet-cooling system. The quality of water is also adversely affected in some stages of energy production from these fuels. On the other hand, solar photovoltaic and wind energy exhibit the lowest demand for water, and could perhaps be considered the most viable renewable options in terms of water withdrawal and consumption.