The Earth receives 174 Petawatts (PW) of incoming solar radiation at the upper atmosphere. Approximately 30 % of its radiation is reflected back to space while the rest of 71 % (124 PW) is absorbed by clouds, oceans and land masses. The world cumulative solar PV installed capacity reached almost 398 Gigawatts (GW) in 2018. This is only about 0.3 % of solar energy utilization from the sun. There is a wide gap of utilization is noticed due to lack of technology. In 1931 selenium cell efficiency of 1% invented then in 1980 thin films cell efficiency of 6-7% introduced. After 2013, efficiency of 18 to 21% achieved by crystalline silicon technology. In India, the installed capacity of till 2018 is of 350 GW which includes renewable and non-renewable energy sources. In that the cumulative installed solar capacity is only about 25 GW. By 2022, India wants to install 175 Gigawatt (GW) of renewable power capacity which corresponds to around half of its total electricity production.
To achieve this capacity by improving solar cell efficiency from 20 % to 40 %, augmentation of grid infrastructure, massive subsidies and skilled manpower of 3 lakhs persons for the next three years to achieve the planned target. Most of the world's population lives in areas with solar insolation levels of 150 to 300 watts/m or 3.5 to 7.0 kWh/m per day. In India, the per capita electricity consumption from 2017 to 2018 was around 1150 to 2000 kWh. The electricity demand in the country will grow at 7 % between FY 2017 and FY 2022 and 57 % of the total electricity capacity will be generated from renewable sources by 2027 as per Central Electricity Authority (CEA). In 2011, a report by the International Energy Agency (IEA) found that solar energy technologies such as photovoltaic, solar hot water and concentrated solar power could provide a third of the world's energy by 2060.