hold the Phone... i don't think this is debunked....and Maybe someone else pointed this out but....i think "solar wall" might be take a bit to literal ...
They would NOT put solar panels on the Mexican side of the wall or anyplace they could be damaged from mexico..so I wouldn't think panels on the actual wall is an option.
the wall includes government controlled land next to it for patrolling the wall. one would assume that they would put a solar farm on the US side next to the wall which would massively increase the total number of solar panels they could place .. this could easily be larger by a factor of 10.
so instead of revenue of ~100m per year your talking revenue of ~1billion per year.
and frankly there building this from the ground up.. there no saying they even have to limit themselves to the size, they could go larger!
This is similar to what we are seeing a lot more of in my area which is solar farms on the side of interstates and sometimes in the median when the distances between the opposing traffic lanes make it feasible