The Full Form of PLF is Plant Load Factor.

Determining the performance of a power plant can be a complex topic to understand, given the various factors such as availability of fuel/water, installed capacity, the age of the unit, planned outage etc, at play. A brief understanding of different aspects of plant load factor may help in enhancing our knowledge on performance parameters for thermal power plants. The Plant Load Factor is commonly considered as a measure of a power plant’s capacity utilisation.

The Central Electricity Regulatory Commission defines Plant Load Factor as a percentage of energy sent out by the power plant corresponding to installed capacity in that period. For example, if a power plant with an installed capacity of 500 MW operates through the day at its maximum load, the energy generated will be: 500 MW X 24hr = 12,000 MWh.

The energy sent out by the plant when operating at 450 MW for 24 hours will be: 450 MW X 24hrs = 10,800 MWh

Plant Load Factor (PLF): 10,800 MWh ÷ 12,000MWh = 0.9 (90%)

A low PLF is bad for the power plant as it indicates that the plant is not being used to its optimal capacity. This will increase the per-unit cost of the power thus produced, making it unattractive for purchase by Discoms. A higher PLF, on the other hand, will generate a greater total output which will reduce the cost per unit of energy generated. The higher the output, the lesser will be cost per unit. The additional energy produced would also result in an increase in revenue of the plant.

In India, the Ministry of Power has, since the early 90s, used the Plant Load Factor as a metric to check the efficiency of a plant. A PLF norm has been set, and incentives are being given to those producers who produce power in excess of the norm. Currently, the flat rate payable for excess generation corresponding to the scheduled generation is 50 paise per kWh as specified in regulation 36 (B) of CERC regulations.

In the last decade, India’s Plant Load Factor for coal-based power plants has seen a steady decline. Here’s a look at the annual average PLF for coal and lignite-based plants from 2009-10.