Are you sure that's not part of pilgrim? It may no longer be powering the active hospital, but I am 995 sure it was previously.
If you take a good look at the older images of Pilgrim, even the architecture looks the same.
I can't seem to find a clear resolution map, but this one from 1938 shows a powerplant in what would be the same place.
http://opacity.us/...grim_map_small.jpg