Given enough solar/wind/battery power i do wonder if a desalination plant could run pretty cheaply. A quick chat with ChatGPT tells me it should be feasible. Roughly investing around 1 billion dollars and around 40 million per year for keeping it run producing around 100.000 m³ per year. Cost price of the water would be around $0.20 per m³. Could run for more than 25 years.