ABSTRACT
Water is used in various processes in coal-fired power plants. The largest amount of water is used to cool down the steam exiting the steam turbines, followed by flue gas desulfurization, dry ash removal, boiler makeup, coal transport and domestic uses. Open-loop cooling systems withdraw significant volumes of water but consume a very small proportion. Closed-loop cooling systems withdraw substantially less water but consume almost all of the water withdrawn. Air-cooling systems require the least water inputs but are less energy efficient. Generating technology and environmental factors also affect a coal power plant’s water use efficiency. Increased river water temperature lowers cooling efficiency and increases water requirements. Compared to coal power generation, wind power and solar PV require negligible amounts of water, mainly for cleaning purposes. Hydropower production also results in substantial water consumption because of evaporation in dammed reservoirs. Concentrated solar power requires water for cooling as well as for cleaning the panels. Natural Gas Combined Cycle and Integrated Gasification Combined Cycle turbines significantly reduce water requirements compared to coal-fired plants due to the efficiency of gas turbines.
