Air pollution is diminishing India's capacity to harness power from the sun, experts say, undermining billions being invested in renewables as the energy-hungry country emerges as a solar superpower.
New research has found the smog and dust is sapping solar power generation by more than 25 percent, far beyond levels previously thought.
In the first study of its kind, U.S. and Indian scientists measured how man-made particles floating in the air and deposited as grime on solar panels combined to seriously impair sunlight from converting to energy.
This interference causes steep drops in power generation, they found.
At present levels in India, it could amount to roughly 3,900 megawatts of lost energy – six times the capacity of its largest solar farm, a gigantic field of 2.5 million panels.
"A simple calculation shows that this is a big amount of energy we are going to lose," Professor Chinmay Ghoroi, who co-authored the paper, told AFP at the Indian Institute of Technology in Gandhinagar.
These huge losses will only compound as India realises its grand solar ambitions, experts say.
Worse than dust
Dust has long been a menace for solar projects in desert states like Rajasthan and Gujarat, where robotic wipers are deployed to ensure panels are cleaned after sandstorms.
But the new research confirmed what solar installers had long suspected – that choking smog from cars, coal plants, crop burning and trash fires was particularly adept at bleeding energy.
The grimy coating that man-made pollutants deposit on solar panels is far more effective at blocking light than dust, and trickier to remove by washing, Bergin and Ghoroi found.
This is especially troublesome in northern India, where fine airborne particles from human activity contribute far more than dust to the dire air quality.
This bodes ill as the government seeks 40 percent of its solar energy from rooftop panels atop industrial zones and urban centres by 2022.
Walking on sunshine
But there is little appetite for gloomy projections as India's solar sector undergoes an unprecedented boom.
Amid this optimism, new milestones are being surpassed at a dizzying speed.
A behemoth solar park nearing completion in India's southeastern Andhra Pradesh state will rival the world's largest.
In May, wholesale solar prices plunged to record lows, cheaper than the coal-powered electricity that overwhelmingly dominates the power grid.
Dr Andre Noble, an expert on the effect of haze on solar generation, found little interest when he presented his findings at a solar summit in Delhi last month.
"People didn't pay much attention," said Noble, who is head of operations and maintenance at Singapore-based Cleantech Solar, which invests heavily in India.
"They might have a gut feeling, but they might think the impact is negligible."
Rutagi said air pollution was brushed off as "a large, macro issue" by an industry fretting about crashing solar prices and obstacles connecting to the grid.
"From a doability perspective, those issues are much more tractable, or solvable, that air quality issues. People have kind of taken it in their stride," he said.AFP
Man-made particles floating in the air and deposited as grime on solar panels seriously impair sunlight from converting to energy. This interference causes steep drops in power generation.