The commercial unit of electrical energy is kilo watt hour (kWh).
1 kWh can be converted to joule as:
1kWh=3.6×106J
The kilowatt-hour (symbolized kWh) is a unit of energy equivalent to one kilowatt (1kW) of power expended for one hour (1h) of time. The kilowatt-hour is not a standard unit in any formal system, but it is commonly used in electrical applications. kWh is the unit of electrical energy, it is same for both commercial as well as domestic. Commercial unit is having different rate of charge and it is more than domestic unit rate. It is basically applied on power consumptionin factories or other business sectors.