Estimation of Hourly Direct Normal Irradiance (DNI) for 22 Stations in India (Revised)

Concentrated Solar Power (CSP) plants require Direct Normal Solar Irradiance (DNI) data for both design and operation. The availability of DNI data, especially with closer time intervals, until 2010-12 was scarce. However, the India Meteorological Department (IMD) published a Typical Meteorological Year (TMY) data on Global Horizontal Irradiance (GHI) and Diffuse Horizontal Irradiance (DHI). The study developed a methodology to use these GHI and DHI data and arrive at DNI.