Nuclear power will generally beat any other source hands down. And now, they are making very stable small reactors that are about the size of a shipping container. This might be a practical intermediate term solution. But in the short term, parking an aircraft carrier offshore can produce a heck of a lot of energy.
I gather in past there has been some concern about permanent desalinization plants, because they can change ocean salinity, which messes up sea life. The solution might be a more complex pipeline, that returns brine to the downstream area near the inlet.
The biggest problem is always “biologicals” that tend to clog the pipes.
Actually there is a technology that was developed over a decade ago, that I helped raise money for. It basically was a unit that went on the bottom of the ocean about 1200+ feet and had a big long pipeline. Pressure pushed the water through the membrane and then a pump took it up. The water is 99% clean and there is not a huge effluent or cleaning issue. I think they have developed some of these in the middle east. I had approached San Diego county about it but they were too nearsighted. Now they are dying for a real solution that doesn’t pollute the coastline.