The performance of a PV power plant is often denominated by a metric called the capacity utilisation factor. It is the ratio of the actual output from a solar plant over the year to the maximum possible output from it for a year under ideal conditions. Capacity utilisation factor is usually expressed in percentage.

Capacity Utilisation Factor(C.U.F) =           (Actual energy from the plant(kwh)) / (Plant Capacity (kwp) x 24 x 365)

The energy generation of a plant primarily depends on two key parameters; solar radiation received and the number of clear sunny days experienced by the plant’s location. These two factors affect the capacity utilization factor as well.

According to the reports from MNRE in 2013, the average capacity utilization factor of solar PV plants in India is in the range of 15-19%.In particular, solar plants in Rajasthan and Telangana have recorded the highest capacity utilization factor; it being in the range of 20%.The geophysical location of these states has helped this cause. Moreover, it is interesting to note that the highest capacity utilization factor was for a Concentrated PV (CPV) plant and it came up to almost 35%.

The C.U.F for several solar friendly states in India and the approximate output per day for a 1kWp plant is given below:

State	CUF (%)	Output for 1 kWp panel (kWh/day)
Gujarat	18	4.32
Karnataka	19	4.56
Madhya Pradesh	19	4.56
Maharashtra	19	4.56
Punjab	19	4.56
Rajasthan	20	4.80
Seemandhra/Telangana	20	4.80
Tamil Nadu	19	4.56
Uttarakhand	19	4.56

 

Note: The calculation is based on average plant performance across each state. Output from a particular location may vary from these estimates.

Most research suggests that the plant load factor and the capacity utilisation factor basically represent the same parameter. The term capacity utilisation factor has replaced plant load factor in many a cases. The C.U.F doesn’t consider the degradation of solar panels and hence technically doesn’t paint a highly accurate picture of the plant’s performance.