I'm a bit confused about why this is a serious engineering problem.

If a gigawatt class DC suddenly needs to take its sensitive IT loads off grid, it could be designed with load banks on site to stand in for the IT load. These would be exceptional use only, so the specific cooling technology (obviously we want to boil water) is not much of an ecological concern. A gigawatt will vaporize ~100 gallons of water per second. How long until the grid can adapt? Five minutes? That's not exactly a heroic amount of water for these projects.