- The interlinking of the world’s growing need for affordable energy and the increasing pressure on the quantity and quality of fresh water supplies – the water-energy nexus – continues to grow in importance.
- Energy and environmental policies that were once quite separate, have progressively converged to reflect the nexus and are now aimed at encouraging responsible water conservation and protecting water quality.
- The largest consumers of coal for power generation globally (China, India, the USA and South Africa) have policies on water use that have been developed in conjunction with national energy needs.
- Through a systematic consideration of the many processes in power generation, schemes for saving water in the cooling stages and pollution control technologies have been identified and implemented and work continues on further savings.
- The concept of zero liquid discharge is the logical technical solution for current and future plants and increasingly, national legislation mandates this approach.
- The higher efficiency of modern new-build coal-fired power plants has the added advantage of a lower water requirement per MW generated.
- The drive to utilise alternative sources of water will become increasingly important. Significant developments have occurred in using readily available supplies such as municipal wastewater, but other sources have a more patchy uptake.
Water issues for coal-fired power plant
Dr Ian Barnes