Could easily just charge separate lines on the bill, just like they do for everything else.
1 - $0.0x c/KWh for line maintenance - this charges on both incoming and outgoing power.
2 - $0.xx c/KWh for power usage - this charges only on the incoming side.
3 - $xx flat fee every month for administration of your account.
Charge what things cost and it won’t matter how your use your energy.