India, due to its geo-physical location, receives solar energy equivalent to nearly 5,000 trillion kWh/year which is equivalent to 600 GW. This is far more than the total energy consumption of the country today. But India produces a very negligible amount of solar energy compared to other energy resources.
Following graph depicts solar energy potential in the country. While India receives solar radiation of 5 to 7 kWh/m2 for 300 to 330 days in a year, power generation potential using solar PV technology is estimated to be around 20MW/sq. km and using solar thermal generation is estimated to be around 35MW/sq. km.
For a Solar Photovoltaic (SPV) project, Capacity Utilization Factor (CUF) is the ratio of actual energy generated by SPV project over the year to the equivalent energy output at its rated capacity over the yearly period.
The energy generation for SPV project depends on solar radiation, measured in kWh/sq m/day and number of clear sunny days.
The output of Solar Cell is measured in terms of Wp (Watt Peak) and refers to nominal power under Standard Test Conditions (STC) (1000 W/m2, 250C, 1.5AM).
According to the Solar Radiation Handbook (2008), published by Solar Energy Centre, MNRE the daily average global radiation incident over India is in the range of 4.3 kWh/Sq m to 5.8 kWh/Sq m.
Also, it is noted that around 290 to 320 clear sunny days are prevalent across most parts of India throughout the year.
Hence, considering an average clear sunny days around 300 and daily average global solar radiation to be around 5.8 kWh/Sq m/day, the capacity utilization factors for various Solar PV based power project installations is expected between 15% to 25 % based on SPV (thin film or crystalline) and up to 35% based on concentrated PV (CPV).