Towards building solar in India - A combined mapping and monitoring approach for creating a new solar atlas

Against the background of rising energy demand and climate change, solar energy applications are expected to become one of the fastest growing sources in India. To support India's solar policy and to respond to a growing demand for high-accuracy solar resource data a new solar resource atlas was created in the study presented. To derive temporal and spatial consistent datasets measured values from 51 ground measurement stations distributed over the whole country were used to derive site-specific correction factors. Another 61 stations were used to validate the resulting maps of long-term monthly-averaged datasets. Correlation factors were transferred to the needed spatial extent using geospatial interpolation and used to adjust satellite-derived data sets with a resolution of approx. 3 × 3 km. Solar datasets created based on the years 1999 to 2014 provide a comprehensive overview of solar resources in India. Long-term averages, annual averages for each month of the year, as well as standard deviations, are presented for all three components of irradiation. The results show that the adjustment using monthly correlation factors significantly improves the quality of long-term estimations from satellite-derived sources and reduces the associated uncertainty.