Utility companies charge based on consumption in kWh. Range of approximately 3 to 10 cents per kWh (rates vary by locale)
So consumption is directly proportional to watts of the load.
A 30 watt light bulb running for 100 hrs
would cost half of what a 60 watt bulb burning for the same time frame.
30 x 100= 3 KWh
60 x 100= 6 kWh
So use LED lights that give same lumens for much less watts of power
