[avernon]

Since you are piggybacking on their system, you'd save on peripheral equipment costs and operating costs, too. The subsystems surrounding these cooling water systems are immense. They need river/lake access for water, giant pumps to feed the makeup water into the system, giant fans running all the time, and even larger pumps to circulate the cooling water after. There is a lot of nickel and dime complexity/cost in things like water purification. I'd be shocked if it only knocked 5% of the cost off.

Plus many facilities have surplus low pressure steam you could use to regenerate your fluid.