1) we here in Germany, for non-standard connections (including using the grid as backup for local generation), have split price between max-power-reached-in-any-15min-rolling-average, and per-kWh.
The former is low-medium single-digits per kW and year, depending on whether you hook up to the 6kV (to neutral; low-voltage would be 240V) medium voltage or they have to keep a 6kV->240V 3-phase transformer ready for you.
At 20-30ct/kWh, this sums up to (assuming low-voltage) 0.3% duty cycle getting you to spend as much on energy as you spend on power/capability.
As for the substation: it doesn't care beyond possibly having to switch some taps that are used to correct for load-current-dependant voltage drop in that 6kV network, but I doubt they get anywhere near their delivered voltage limits in normal operation, anyways.
At 20-30ct/kWh, this sums up to (assuming low-voltage) 0.3% duty cycle getting you to spend as much on energy as you spend on power/capability.
As for the substation: it doesn't care beyond possibly having to switch some taps that are used to correct for load-current-dependant voltage drop in that 6kV network, but I doubt they get anywhere near their delivered voltage limits in normal operation, anyways.