I drove by Tuesday afternoon on my way from DC to Durham NC. There was a crew working on the site at the time; I didn't want to disturb them so I just took one photo of the equipment. They weren't really anywhere near the photo; they were digging off-camera to the left, on the far end, i.e. in front of the stall that's closest to the mall.
Interestingly, I see a 5th supercharger cabinet in the photo on the left that looks a little different from the other 4 (and is also open on the bottom). I think it would be strange to only add 2 stalls here, so I wonder if either (a) there's another set of cabinets behind the ones in the photo, or (b) they haven't added more yet because they need to expand the fenced area or make other changes to the site first. I suppose possibility (c) is they only have enough power / space / permission for 2 more stalls. I didn't notice the 5th cabinet till I looked at the photo that night, otherwise I might've looked from a couple different angles.