> "WIND" or "Solar" is not going to replace 3,500 MW of nuclear power without damaging a LOT of land.
Well, let's see. Wind uses negligible land if incorporated onto farms, so I'll assume it's all solar.
Nuclear capacity factor (fraction of the time it's operating): 0.9, call it 100%.
PV capacity factor 0.2
PV nameplate panel production per square metre 200W
PV land coverage fraction (access paths beside PV panels take up space) 0.5
Total land needed for PV to deliver equivalent power:
3 500 000 000 / (200 * 0.2 * 0.5) = 175 000 000 m^2 = 175 km^2.
Switzerland's population is 8.5M. Assuming it is 80% urbanised and 20 m^2 per person in cities (less than in Dhaka, 8.9M / 306 km^2): then Switzerland's cities take up 136 km^2. In reality, probably several times this figure.
So the land area is probably less than Switzerland's cities.
If Switzerland wished to accelerate the development of two-layer PV cells, increasing production per area by 50%, then the bulk of the 3.5GW could be provided by rooftop solar in cities.
In reality a mix of wind and PV would be used. Wind is highly compatible with pastoral farming, leaving 90% or more of the land area it "occupies" free for grazing.
The real challenge at present would be sourcing enough storage for the daily usage cycle.
Now, damage. Covering land with inert PV panels does indeed change the soil ecology, but not irremediably. Remove the panels, and the soil would be back to normal inside a decade. Contrast with coal mines and ash piles, and uranium mines. And, as above, the PV could all be on rooftops, which have already damaged the land. Get rid of the buildings!
TLDR: the "LOT of land" is not much, really, and the damage is minimal.