Not all buildings have complex clearance, but the ones that will have complex clearance are going to be the coal generator, fuel generator, nuclear power plant, train platforms, train station, refinery, particle accelerator, resource sink, and the space elevator.

So yeah, that's going to be pretty nice.

A lot of people gave a lot of feedback on that as well, and you're a little disappointed that you couldn't use that empty space, but now you can.