A combined cycle coal plant has a gas turbine air intake system that includes an evaporative cooler. The cooler is operated depending on meteorological conditions (warm air temperature or high humidity, for example). The cooled airflow then supplies air to the natural-gas turbine. When humidity is high and there are water droplets on the turbine blades, the blades begin to deteriorate. This leads to higher maintenance costs. In extreme situations, the turbine can break and force its replacement. Therefore, it is imperative that the cooler function as expected.