Why is desalination so difficult?

Is not just a question of preferences, there are risks also.

If the problem is that we need lots of energy to create pressure to separate salt from brine, well... I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom.

The problem would be to calculate if moving all this weight up and down the sea (and in open sea) would be economical or not. Or of would unavoidably lead to people cutting corners and release part of the salt to the deep water ecosystems. Deep water masses are salty yet so a small amount of salt would impact less here than if released on surface, thats for sure.

In any case, physic laws about density and mass are our friend. Things either float or sink without extra energy added.

> may be they should move

As if immigration isn't a hugely fraught political topic. And you might want to consider how many people moved to Israel and why.

a little from column A, a little from column B

Having all of this in mind, I would go further and propose to regulate by law changing the material of the deep sea submarine ballasts.

It seems technically doable and would have some benefits

1) Lesser impact on deep sea ecosystems. No human trace left behind.

Disposable loads of iron or concrete will remain forever in the bottom. If we use salt or sand instead the impact on fragile deep sea ecosystems seems reduced. The organisms there are adapted naturally to deal with very salty water. The sand or salt ballast could be released gradually over a bigger surface reducing even more the impact over a particular spot or colony

2) Improved economics?

To dump valuable iron made with valuable energy into the sea seems a suboptimal solution. Substitute it with some common by products that are yet in the area and don't need to be transported from a mine far away could save some money probably. Containers of ballast would be fully recyclable also.

Ships could be adapted to literally making part the ballast on the open sea while in campaign, instead to need to carry all of it from a port.

3) Extra safety.

If your load weight gets stuck by a net you are trapped in the bottom forever, With a ballast of sand or salt you have the extra possibility of open a few escape valves and let the concentrated salt go away. You can also release part of the weight much more gradually. After a while the submarine would tend to float and ascend automatically even if the energy supply would have been entirely lost in an accident.

Having the machine on the surface (or closer to the surface) would save millions and would made a big difference on humanitary and economical aspects of the rescue operation. A damaged submarine can be still repaired. Building another would be much more expensive.

Dunno about the possible negative aspects, more volume required for example, but would deserve thinking about it a little more.

Actually solar powered desalination makes a lot more sence - solar is much cheaper and you don't need 24/7 properties of nuclear. so you are overpaying for no reason.

We cam store huge quantities of water, sometimes a year's worth. So intermittency is not a prohlem.

The idea of floating nuclear reactors used for whatever was floating around for a while, but won't happen with government support. It is really just another approach to modular reactors, not a terrible one, but free market wont do it.

What would make more sence, is making all our large cargo ships nuclear powered, and reducing emissions that way