They dump it because it's not cool anymore and nobody is wanting to buy hot water from them at a cost that makes it worth their while.
If they had the capability to cool the water fast enough then they'd use a closed loop cooling system and wouldn't need to pump fresh, cool groundwater.
This is basically how we cool our house in Montana during the summers. Cold water is pumped up one well and hot water is returned down another well. It uses much less electricity than a conventional AC system.
Wow. I've thought about this, using tap water to cool the house, but it's so wasteful it was never more than a playful thought. But then the Netherlands' summers are reasonably survivable even if they make me feel shit all day and all night.
Fine but why not pump it out onto some crops? Here I am paying to heat water for my house and pool -- I should move next door to Google and hook up to their drain pipe.
Yes, I don't get it either. The article implies that they reuse it for a while, and then dump. But I can imagine how filter and ion-exchange systems need water for back-flushing and other maintenance. So maybe there's some hard-to-avoid loss.
If they had the capability to cool the water fast enough then they'd use a closed loop cooling system and wouldn't need to pump fresh, cool groundwater.