Nuclear fission is not renewable. It relies on mined uranium, which is rather limited.
Also, cooling towers are not seen exclusively with nuclear power plants. Many chemical refineries need lots of process heat and need to get rid of that as well. Evaporating water to steam is a great way to disperse excess heat.
Any kind of heat power plant also needs some way to expel excess steam, so oil and gas plants have them as well, just usually different designs.