With fresh water becoming increasingly scarce in many regions of the world, a recent article in Power Engineering International magazine looks at the growing popularity of using less water – or none at all – to cool coal-fired power plants, and references several SPX dry cooling system installations around the world.
Turning coal into electricity is a highly water-intensive process. Traditional coal power plants need water to create the steam that turn the turbines and then more water to cool the steam and minimize back pressure on the turbine.
The World Resources Institute, meanwhile, reports that baseline water stress is becoming increasingly severe in every continent, particularly in much of Asia and along the West Coast of the United States.
With nearly 1,200 new coal-fired power plants proposed around the world, the bulk of which are proposed for water-stressed India and China, power producers are often turning toward to dry-cooling and hybrid-cooling systems that use air to cool the steam being generated.
The article explains that a dry-cooling plant requires 90 percent less water, though capital and operating costs are higher and thermal efficiency is often lower. Hybrid plants can use dry-cooling on cooler days and switch over to wet-cooling in hot weather as air-cooling becomes increasingly less efficient.
As the article points out, SPX Cooling Technologies has completed numerous dry-cooling installations around the world, including the Zhengian, Zuoquan, Qinling and WuAn plants in China. They are currently working on a 4.8 GW air-cooled condenser at the new Kusile power plant in South Africa.
