What's left to figure out is the ratio of panels to water to land, and in turn whether the long term value of the land is worth the investment. (Dubai would argue it is.)
While brine can impact local salinity, so does treated-effluent outflows (mixed together they are neutral.) Regardless elevated brine levels drop off sharply from the point of outflow.
If it's profitable, it'll be implemented all over, and underestimating that cumulative effect is something we would plead willful ignorance on as we have done with other industries in the past.
Second point I will try to make, habitats are often unique and small, we would just want to make sure an ecosystem is truly ubiquitous before destroying a small pocket of ecosystem.
Especially now, there are animals that live in just one or few specific spots. We should be careful.
That's because almost all the water that is taken out of the ocean will make its way back to the ocean. We just borrow it for a while.
If all the water used by humans were taken from the ocean, we'd take about 1/300000th of the ocean's water per year. Most of that will be back in the ocean within 200 years. That puts the cap on the amount of water that would be missing from the ocean of 1/1500th of its volume, which means that the steady state increase in salt concentration would be less than 0.1%, which is much less than the natural variation in ocean salt levels.
1) cheaper energy means you can mix more water in to get whatever salt level you want.
2) you can mix in the output of your sewage plants
3) most water is borrowed and returned, not a huge net loss. Every toilet full returns to the ocean, every washing machine run, etc.
WRONG WRONG!!!
No, we used the brines to create even more batries which store our solar charge Now we have POWER at day and at NIGHT. 24/7. 247 we are producing the brines, but then that goes onto make more batries. Ain't no ecosystem destroyed here (though I'm sure people will try to perform a regression of muh bad event unto muh new technology because that is a timelessly vogue thing to do)
Btw touristic heaters are based on https://en.m.wikipedia.org/wiki/Sodium_acetate and that's also energy storage
Compared to the amount of water that is naturally desalinated every day (ie via evaporation), even large scale desalination is a drop in the bucket.
Desalination is already operating on a massive scale in the middle east, and we're not seeing any medium scale effects there. Elevated salinity dissipates very quickly from the point of outflow.
I've not seen any evidence supporting this is the case, but the opposite; large swathes of high-saline concentrated blobs sweeping accross the sealife, killing it. We've had to build specialized very long outflow pipes to give the brine even a change to level