Energy and water security are crucial to human and economic development. Significant amounts of water are needed in almost all energy generation-processes, from generating hydropower, to cooling and other purposes in thermal power plants (see Figure 1), to extracting and processing fuels. However, current energy planning often fails to account for existing and future water constraints. Water scarcity can threaten the long-term viability of energy projects and, conversely, energy processes can impact water resources and limit the water available for other users. Therefore, understanding the water–energy interrelationship is critical to building more resilient and sustainable energy systems. Not taking water insecurity into account in planning can – apart from affecting a country’s economic growth - also lead to fragility and conflict.
Understanding the Water–Energy Nexus in South Africa
The water–energy challenges in South Africa are complex. They include:
- aging infrastructure struggling to achieve an ambitious development agenda without compromising natural resources and the environment;
- water scarcity with stressed basins and strict water-allocation regimes, with most of the country’s water already allocated;
- pressure to move away from a coal-based economy, which currently accounts for 80% of the primary energy supply;
- ongoing electricity crisis leading to power shortages that impact economic activity; and
- uncertainties caused by climate change.
As a first step to understanding the water–energy nexus in South Africa, the World Bank has partnered with the Energy Research Center of the University of Cape Town (UCT) through the Thirsty Energy Initiative to incorporate water constraints into its energy-planning model and foster a more sustainable system. The development of the water-smart energy model and the initiative’s main conclusions are documented in the report “Modeling the Water–Energy Nexus: How Do Water Constraints Affect Energy Planning in South Africa?” The research incorporated a representation of water supply and infrastructure costs into the energy model SATIM to better reflect the interdependence of water and energy in South Africa and the water supply challenges facing the energy system.