10 b] Discuss how electricity bill is calculated based on unit which is consumption of electrical energy for domestic consumers.
Solution :
UNIT: The unit of electrical energy consumed is kWh. One kilowatt-hour is the electrical energy consumed by an electrical appliance of power 1 kW when it is used for one hour. Therefore 1kwh =1 unit.
Calculation of electricity bill for low tension domestic consumer is as follows.
The electricity bill consists of two components: fixed charges and variable charges (running charges). It can be expressed as:
Total Electricity Bill = [A (kW) + B (kWh)] + Tax
Where, Fixed charges – A = charge per kW of max demand
A= Total kW X charge per kW
Example: if the sanctioned load is 3KW then A= [1×85 + 2×95] = 275rs
(Note: For 1kw it is 85 rs and above 1kw it 95 rs per kw)
Where Variable charges – B = charge per kwh of energy consumed.
B = No of units consumed x rate per unit
Example: If the no of units consumed is 120 units then
B = [50 x4.1 + 50 x 5.55+ 20 x 7.1] = 624 rs
(Note: For 0- 50 units – 4.1 rs per unit, 50- 100 units – 5.55 rs , 100- 200 units – 7.1rs)
Therefore Total Electricity bill for given example is
= 275 +624+ Tax.
