Question

A generating station has a maximum demand of 500 MW. The annual load factor is 50 percent. The energy generated per annum will be:
1. 2.19 × 10⁶ MWhr
2. 600 MWhr
3. 250 MWhr
4. 7.50 × 10⁶ MWhr

Answer 1

Correct Answer - Option 1 : 2.19 × 10⁶ MWhr

Concept:

Load factor: The ratio of average load to the maximum demand during a given period is known as the load factor.

Load factor = average load / maximum demand

Energy generated (units generated) = Average load x Time (T)

If the plant is in the operation for T hours

\(Load\;factor = \frac{{Avearge\;load × T}}{{Maximum\;demand × T}}\)

\(= \frac{{Units\;generated\;in\;T\;hours}}{{Maximum\;demand × T}}\)

Units generated/annum = Maximum demand × Load factor × Hours in a year

Calculation:

Given,

Maximum demand = 500 MW

Annual load factor  = 50%

Hours in a year = 8760 hours

Units generated per annum = 500 × 0.5 × 8760 = 2.19 × 106 MWhr

Therefore units generated per year is 2.19 × 106 MWhr

Points to remember:

• The load factor may be daily load factor, monthly or annually if the period considered is a day or month or year
• Load factor is always less than 1 because the average load is smaller than the maximum demand
• It plays a key role in determining the overall cost per unit generated
• Higher the load factor of the power station, lesser will be the cost per unit generated, it is because higher load factor means lesser maximum demand
• The station capacity is so selected that it must meet the maximum demand
• Now, lower maximum demand means a lower capacity of the plant which reduces the cost of the plant