Solar sites must not delete future needed land

In the light of 7 billion of us now on earth it would seem prudent to be as careful as possible with the use of land.
The footprint of solar, where it is otherwise unused or useless is a good sourse of green energy but where it covers land that may be needed there is an imperative to find other sites.
My Wasphead concept provides this at sea in conjunction with other natural harvesting of energies. The nature of placement of solar panels (eg 1x1 metres ) on such an island would be such, like tiles overlapping on a roof, that these allow potable water collection at the same time.
The footprint of the island, being approx 10 sq kilometers would accommodate some 1,750,000 panel of the size mentioned above.