I figured that one was non-serious and just used as anchoring and to take the heat whilst other large ones were ok to go under the radar.
A person who has never built anything before, who claims to be about to build the world's largest building, can be treated with some skepticism.
It's not the only GW datacenter planned [1]. AFAIK, a majority of these big datacenters are going to produce their power via natural gas turbines. I don't know of any that are actually planning on powering themselves via renewables or even nuclear power.
The sub 100MW data centers are mostly relying on the grid, but even a number of them plan on having natural gas turbines.
[1] https://cleanview.co/data-centers/us