According to a new study, airborne particles and their accumulation on solar cells are cutting energy output by more than 25 percent in certain parts of the world. The regions hardest hit are also those investing the most in solar energy installations: China, India and the Arabian Peninsula.
The study appears online June 23 in Environmental Science & Technology Letters.
"My colleagues in India were showing off some of their rooftop solar installations, and I was blown away by how dirty the panels were," said Michael Bergin, professor of civil and environmental engineering at Duke University and lead author of the study. "I thought the dirt had to affect their efficiencies, but there weren't any studies out there estimating the losses. So we put together a comprehensive model to do just that."
With colleagues at the Indian Institute of Technology-Gandhinagar and the University of Wisconsin at Madison, Bergin measured the decrease in solar energy gathered by the IITGN's solar panels as they became dirtier over time. The data showed a 50-percent jump in efficiency each time the panels were cleaned after being left alone for several weeks.
The researchers also sampled the grime to analyze its composition, revealing that 92 percent was dust while the remaining fraction was composed of carbon and ion pollutants from human activity. While this may sound like a small amount, light is blocked more efficiently by smaller man-made particles than by natural dust. As a result, the human contributions to energy loss are much greater than those from dust, making the two sources roughly equal antagonists in this case.
"The manmade particles are also small and sticky, making them much more difficult to clean off," said Bergin. "You might think you could just clean the solar panels more often, but the more you clean them, the higher your risk of damaging them."
Having previously analyzed pollutants discoloring India's Taj Mahal, Bergin already had a good idea of how these different particles react to sunlight. Using his earlier work as a base, he created an equation that accurately estimates the amount of sunlight blocked by different compositions of solar panel dust and pollution buildup.
But grimy buildup on solar panels isn't the only thing blocking sunlight--the ambient particles in the air also have a screening effect.
Read more at Air Pollution Casts Shadow over Solar Energy Production
No comments:
Post a Comment