Yes and no. If I draw an extra 10 kWh one random hour and export 10 kWh back at some other random hour, this costs the utility essentially nothing. The transfor

Yes and no. If I draw an extra 10 kWh one random hour and export 10 kWh back at some other random hour, this costs the utility essentially nothing. The transformer is already there, and other customers near me will consume it possibly without even involving the transformer. (I say “essentially” because there is some tiny loss in the system, but that’s maybe 2%, not 70%.)