Assessing the future solar resources over India at 1.5°C and 2°C warming worlds

India aspires to increase its reliance on renewable energy sources to fulfil its climate commitments. Among renewables, Solar Photovoltaic (SPV) energy has grown rapidly around the world, including in India. However, little is known about how solar dimming and global warming may affect solar power over the region in the future. The production of SPV energy is influenced by meteorological parameters, highlighting the concerns related to grid stability, intermittency, and reliability caused by weather-induced variability.  

Under the Paris Agreement, all the nations agree to restrict the global warming to “well below” 2°C above pre-industrial levels and, if possible, “pursue” efforts to limit warming at 1.5°C. Therefore, it is imperative to understand future climate change and their spatial heterogeneity at 1.5°C and 2°C warming for developing  strategies for renewables.

This research examines the distribution and variability of India's solar resources by utilising state-of-art global climate models from Coupled Model Intercomparison Project phase 6 (CMIP6) and CMIP6 - NASA Earth eXchange Global Daily Downscaled Projections (NEX-GDDP). The analysis of global mean temperature changes reveals that the 2030s and 2040s will be the decade when majority CMIP6 models reach 1.5°C and 2°C warming under SSP2-4.5 (intermediate emission pathways) and SSP5-8.5 (high emission) scenarios respectively with respect to  pre-industrial period (1850–1900).

We find that under the intermediate (high) emission scenarios, the annual mean surface solar radiation over the Indian landmass will decrease by -8±3 Wm^-2 (-5±2 Wm-²) relative to the baseline period (1985-2014) at 1.5°C global warming. An additional 0.5°C of warming (at a global warming level of 2°C) results in a comparatively smaller decline in surface solar irradiance with respect to baseline under both scenarios. At 1.5°C and 2.0°C global warming, most regions are anticipated to experience an increase in surface irradiance under the SSP5-8.5 scenario, as compared to SSP2-4.5. The magnitude and direction of change of aerosols, clouds and associated meteorological parameters needs to be explored further. 

This research will contribute to crucial planning and decision-making processes concerning India and other nations with similar interests.