Notice the size of the conduit for the backfilled one. The size and the fact they are grouped the way they are in that narrow slot indicates transformer. The other pad is much larger to accommodate both the distribution panels and the Supercharger cabinets. There will be conduit coming from the transformer to the distribution panels, from the panels to the Supercharger cabinets and from the Supercharger cabinets to the charging station.I assumed the one that is already backfilled is the one for the charger cabinets, because it had 8-9 conduits running to it. Also, the contractor wouldn't have to wait for the power company, to complete that side. I assumed the other side was for the supply transformer, because they have to wait for the power company to come out for that segment. That was just my guess though