Honestly power isn't even the biggest problem with desalination, it's the spectacular volume of brine commensurate with the volume of clean water you are trying

Honestly power isn't even the biggest problem with desalination, it's the spectacular volume of brine commensurate with the volume of clean water you are trying to extract: figuring out both how to dispose of it without creating new environmental hazards and constantly repairing/replacing the machinery which must filter and plumb that caustic sludge. Which is all to say in addition to the crazy energy demands of desalinization, there are also problems that dwarf those.