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You are describing WYE connected for 480/277, that is the only was I have ever seen 480 volt done. At .03 per kWh it will be very difficult to break even, we're paying more like .27-.46 /kWh depending how energy efficient you are. We have a base line of several hundred kWh at base rate then you go up the tiers depending on your use, energy hogs during the summers heat pay near .50 per kWh but this is California, the land of regulate you to death, I haven't had a utility connection in years.
Floating delta has no neutral.....loads are phase to phase only, there is no 120 volts. Have you ever seen corner grounded delta......AKA Grounded B phase....no neutral .....phase to phase 240 volts .....A phase to ground 240 volts .....B phase grounded 0 volts...C phase to ground 240 volts.  No 120 volts, balanced loading only....very rare indeed, I found it on a farm feeding a 15 horsepower turbine pump. It took me a while to figure out what I had. It was not documented anywhere.....Only a few senior t-men even knew what I was dealing with....Schneider had never heard of it and was unwilling to supply Equiptment for this installation. I bought a new 240 volt Schneider Square D well pump controller and hacked it for this pump. It worked fine but distributor would not sell me the Equiptment to use on that job. I told them this one was for a different job. PG&E 's workers looked the other way. I had a faux artist paint the new Equiptment old to fool the supervisors......they did not notice the "painted rust".......LOL...painted dents and all...I got to did out my photos of this one......sometimes that is the only way to get things done here in the land of over regulation.  Government regulators need to be treated like mushrooms...feed them $hit and keep them in the dark....