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Instead of siting polar panels in the desert, it would be overwhelmingly more efficient use of resources to float the solar panels on the canals and reservoirs involved, cutting evaporation and bio-fouling while keeping the panels cool for better efficiency and longevity, and also more easily cleaned of dust. California has begun experimenting with PV on canals, while in India it is already in full production. So, panel area is moot.

Brine may be returned to the sea via a long leaky hose, eliminating effects of excess salt concentration on wildlife by distribution along its length. There is no need to produce extremely concentrated brine, anyway: there is plenty of seawater, and it takes less energy to extract fresh water from less-concentrated brine.

You don’t need expensive PV and reverse osmosis to separate fresh water from brine: greenhouses can do the job at much less capital cost, with incoming water used to cool the glass that fresh water will condense onto the bottom of, and heat exchanged from outgoing brine to incoming brine after it drains off the condenser and spreads out over black evaporation pans.

In some places, condensing the fresh water is unnecessary; the water vapor may be released for the wind to carry off, to rain out into mountain streams collected behind alpine dams. North/central California is ideally situated for this mode, with myriad dams in long use in the Sierra Nevada range.

Hawaii successfully demonstrated using deep sea water solely as a coolant to condense fresh water directly from ambient humidity.