- India aims to install 100 GW of solar energy by 2030 as part of its climate mitigation strategy.
- A new study highlights that rising air pollution and climate change could reduce solar photovoltaic efficiency.
- The researchers say that addressing air pollution and climate change is essential for maximising India’s solar potential.
With plans to install 100 GW of solar energy by 2030, India has positioned solar energy at the centre of its strategy to mitigate climate change. However, changing weather and high pollution will reduce the efficacy of solar photovoltaics (SPV) in the future, according to a new study published in Environmental Research Letters.
Researchers from the Centre for Atmospheric Sciences, Indian Institute of Technology (IIT) Delhi used radiation data from global climate models available under the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to analyse the twin impacts of climate change and air pollution on SPV performance. The CMIP6 is a leading group of models that uses different data sets to project the future impacts of climate change under various emission scenarios.
The study, using data from 1985 to 2014 as a baseline to predict a change from 2041 to 2050, concludes that SPV’s efficacy may decrease by 3.3% by the middle of the century. Based on current solar power production levels, the study estimates a loss of 600 to 840 gigawatt-hours (GWh) of electricity annually.
PV power generation at a specific location is determined by the nominal installed PV capacity and the PV potential at that site. The potential depends on the availability of solar radiation and other factors such as ambient temperature, surface winds, and humidity.
As local ambient conditions play a significant role in the overall performance of solar panels, the paper talks about two possible future scenarios. The first scenario involves moderate efforts to reduce air pollution and address climate change. The second one includes conditions where there is strong air pollution control but less action to combat climate change.
The study concludes that SPV performance declines more significantly in the first scenario, which involves moderate efforts for both air pollution control and climate mitigation, compared to the second scenario with strong air pollution control measures.
“Clean air and clean energy must go hand in hand—curbing air pollution can reduce radiation-induced PV losses, while urgent climate action can mitigate temperature-induced losses, ensuring the full utilisation of solar potential and fostering climate-resilient growth,” said Sagnik Dey, one of the authors and professor at the Centre for Atmospheric Sciences, IIT Delhi.
India plans to achieve 500 GW of non-fossil-based electricity generation capacity by 2030. Of this, 100 GW is expected to be solar. As India marches ahead with its solar ambitions, it is essential to address efficiency losses that may hamper its PV potential in the future.
Abundant but declining solar resource
India receives around 300 sunny days each year and solar radiation levels ranging from 1700 to 2200 kilowatt-hours per square meter annually, the paper says. However, due to anthropogenic aerosols, India has seen a continuous decline in incoming solar radiation, a phenomenon called dimming.
The paper also explores the impact of increasing temperature on solar panels, which includes several solar cells. These solar cells convert solar light and are affected by local ambient conditions. According to the researchers, average daily maximum cell temperatures in India ranged from 15 degrees Celsius to 50 degrees Celsius from 1985 to 2014, while solar panels typically perform at maximum efficiency when cell temperatures do not exceed 45 degrees Celsius.
The paper states that cell temperatures are expected to exceed 45 degrees Celsius for approximately 18 ± 5 days under moderate efforts to control pollution and climate change and for 26 ± 3 days under strong pollution control measures but weak climate action scenarios in the future. This indicates a greater risk of power loss due to heat exposure under both scenarios. Researchers say that elevated cell temperatures, driven by rising surface temperature, are thus a significant concern for future PV potential.
The study highlights that most regions in India will see a rise in aerosols, except the northwest Thar Desert, where clouds will play a more significant role despite high dust levels. Along with aerosols, higher temperatures will reduce the efficiency of solar panels, causing significant performance losses, especially with limited climate action. “A rapid transition to renewable energy is crucial to mitigate both air pollution and climate change,” notes the study.
Diverse geographic impact
The study uses two metrics to analyse solar energy potential: the total number of solar-rich days per year and the number of consecutive solar-rich days and its impact on power grids divided into five zones: northern, eastern, western, northeastern, and southern.
According to the paper, India gets around 215 solar-rich days per year when the incoming solar radiation exceeds 208 watts per square metre, which is considered necessary for PV generation. Southern, western, and northern power grids receive more such days than the eastern and northeastern grids. However, weak air pollution controls could reduce this by up to 15 days per year, while medium efforts may limit the reduction to about eight days.
The second metric, the consecutive solar-rich days, tracks uninterrupted solar radiation. India gets around 165 such days annually, with the northern region having the most and the northeastern grids the fewest. Under weak air pollution controls, these consecutive days could drop by up to 20 days, compared to 15 days with moderate measures. High pollution levels, linked to increased aerosols, are the main reason for the decline in solar radiation.
The paper concludes that the number of solar-rich days is likely to decrease, with the maximum reductions in highly irradiated regions like the northwest and the western power grid. As a result, the northern, western, and southern power grids—home to most of the country’s solar parks—will face significant challenges in maintaining SPV performance due to climate change.
The impact on regional power grids would also depend on future air pollution control measures and climate action. For instance, the northeastern grid is projected to report an increase in solar radiation under strong air pollution mitigation and weak climate action scenarios. This could potentially increase the number of solar-rich days available in the region. Researchers have attributed this increase to a decline in clouds over the region. Both eastern and northeastern power grids traditionally see fewer solar-rich days.
“The north-east power grid, with approximately 125 solar-rich days annually, holds potential for solar energy development. Its minimal susceptibility to temperature-induced PV efficiency losses makes it a promising region for existing solar parks and planned solar cities,” Sushovan Ghosh, lead and corresponding author of the paper, who was a researcher at IIT Delhi and now at the Earth Science Department, Barcelona Super Computing Center, Spain.
Irrespective of which meteorological factor plays a more significant role in the overall process, a declining trend of solar radiation is projected for most of the country during 2041-2050.
The paper says that in the first scenario, with moderate efforts to control air pollution and climate change, the eastern power grid, especially the eastern Indo-Gangetic Plain, is expected to experience the largest decline in solar energy potential (−5.1%), followed by the northern (−3.4%), northeastern (−3%), and southern (−2.3%) grids. In the second scenario, with strong air pollution control but weak climate action, the western grid is expected to see the largest drop (−2.7%), followed by the northern (−2.4%), eastern (−2.2%), and the smallest drop in the northeastern grid (−1.1%).
“Our analysis reveals that, during mid-century, aerosol-induced radiation losses will surpass temperature-induced losses annually, except in parts of the northeastern region and the southern coast near Kerala, highlighting region-specific variability in solar energy challenges,” said Dilip Ganguly, one of the co-authors and professor at the Centre for Atmospheric Sciences, IIT Delhi.
According to experts, the study highlights how securing a sustainable future could get even more challenging amid the rising threats of climate change and air pollution. “Integrating climate resilience into solar infrastructure would ensure long-term reliability, maximise solar energy generation, attract foreign investments, reduce costs, and support India’s goals of clean, sustainable energy,” said Asutosh Acharya, a chief climate scientist at Aurassure, a climate tech company specialising in hyperlocal climate data monitoring and physical risk analysis.
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Banner image: A solar power plant in Gujarat. PV power generation depends on the installed PV capacity and the site’s PV potential. Image by Citizenmj via Wikimedia Commons (CC-BY-SA-3.0).
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