A kilowatt (kW) is power, the rate a device draws; a kilowatt-hour (kWh) is energy, power sustained over time. A 150 W bulb draws 0.15 kW and consumes 0.15 kWh in an hour. In a parking facility:
- Chargers and service loads are sized in kW; utility bills and charging fees are settled in kWh.
- The paper’s planning rate: about 3.1 miles of range gained per kWh delivered for current BEVs.
Considerations
- Selling energy by the kWh makes the charger a commercial measuring device subject to metrology law. kW builds the system; kWh pays for it.