Definition- Load factor(LF) is defined as the ratio of the average load to the maximum demand over a given period. The average power can be calculated by calculating the total energy consumed for that period and then dividing the total energy by the time period. Thus, the average power is ;
Now, we can define load factor(LF) as ;
Importance of Load Factor
The load factor is very important because, by use of this factor, you can calculate the unit cost of electricity generation. The higher LF of the power station leads to lower electricity generation costs. Thus, this factor shows how efficiently you use energy.
Higher Load Factor – Lower Generation Cost
Lower Load Factor – Higher Generation Cost
Load Factor Formulas
The average power-to-peak power ratio for a certain time period is called the load factor. we can choose the time period as daily, weekly, monthly, or annually.
Daily LF
For daily LF calculations, we take a time period of 24 hours. and, its formula is;
Monthly LF
If you calculate the energy consumed in a month and the maximum or peak power during the month, you can find out the monthly LF. The formula is given below;
Annual LF
If you calculate the energy consumed in a year and the maximum or peak power during the year, you can find out the annual LF. The formula is given below;
Now, let us understand the LF by taking examples.
Load Factor Example Question
The following three parameters are required for LF calculations.
- Actual energy consumed (kWh)
- Peak Power(kW)
- Time ( Hours)
Example 1:
The maximum demand for a power generating plant is 3000 kW. If the number of units (in kWh) generation per year is 18 ☓ 106. Determine the annual LF of the plant.
Solution-
Annual LF
Example 2:
The maximum demand from the load side is 100kW, and monthly unit consumption is 50000. Calculate monthly load factor.
Monthly LF
The value of LF can not be equal to 1 because the average power is always less than the maximum demand.
The high LF indicates that the power utilization is relatively constant and if it is low means the demand set is high.
Example 3:
Calculate the load factor for the load pattern shown in the below graph.
First, we will calculate the energy consumed during 24 hours.
The average load during 24 hours is;
From the above graph, the maximum load= 500 kW
Therefore, the LF is;
How to Improve LF?
The LF can be improved by either increasing the average load or by decreasing the maximum demand. The reduction in the maximum demand is a better option. The maximum demand can be reduced by shifting the electrical load from the peak time of the day to the non-peak time.
For example, there are five machines; if we run all these machines at a time, then the maximum demand will be more. Instead of running machines at a time, we can scatter the operation of machines at different times of the day and improve the load factor.
