Yes, this plant is not nuclear despite having nuclear cooling towers (rumor is, they were building a nuclear plant but switched to coal after the towers were built). I'm currently doing research about this plant, trying to obtain as much information as I can.
Hyperbolic concrete cooling towers are not exclusive to nuclear power plants. Thermal (i.e. steam) power plants of any type, be they coal, oil, gas, nuclear, CCGT, can and do utilise these types of towers depending on design/location.
Power - Coal 
fmpa.com/index.php/power-generation/power-facilities/stanton-energy-center