CUF vs PLF

While working with multiple O&M teams across large utility-scale solar power plants in India, we have often seen people being confused about 2 critical parameters to evaluate the performance of a solar power plant — Capacity Utilization Factor (CUF) and Plant Load Factor (PLF).

Both these parameters are quite similar but give slightly different information about the plant and are often considered the same by O&M teams. Here’s our simple explanation of the two parameters that can help draw the distinction.

Capacity Utilization Factor (CUF)

It is the ratio of actual output produced from the solar power plant over the year to the AC plant capacity multiplied by no. of hours in the year. In other words, CUF signifies the ratio of actual production to the production capacity of a plant in a particular year.

or, CUF = Total units (in a year) / (AC plant capacity×365×24)

Plant Load Factor (PLF)

It is the ratio of actual output produced from the solar power plant over the year to the DC plant capacity multiplied by no. of hours in the year. In other words, PLF indicates how well the DC system of plants is utilized in a particular year.

or, PLF = Total units (in a year) / (DC plant capacity ×365×24)

So, the basic difference between CUF and PLF is that you need AC plant capacity to calculate CUF and DC plant capacity to calculate PLF for a plant. For both CUF & PLF, a higher value indicates a better output from the plant, but a further deep-dive into the influence of radiation can help in developing a better understanding of plant performance. Stay tuned to for the next article on the best way to account for radiation.