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Why do condensing steam turbines require large quantities of cooling water?

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Rows of white wind turbines with spinning blades stand on a dry, grassy landscape at a wind farm near Tehachapi, California. — turbine Wind turbines near Tehachapi, California.

Condensing steam turbines require large quantities of cooling water to effectively carry away the heat released during the phase change of steam into liquid water.1

In these systems, steam is expanded to pressures significantly below atmospheric pressure—often 90 to 100 kilopascals lower—to maximize the expansion of the steam and increase the change in enthalpy. This process allows the turbine to extract more energy from the steam, resulting in higher work output and greater overall efficiency compared to noncondensing turbines.1

Because the steam must be condensed to maintain these low pressures and complete the Rankine cycle, a condenser is used to remove the latent heat from the vapor. Large volumes of water are necessary to act as the cooling medium to facilitate this heat transfer, ensuring the system operates at peak efficiency.123