Two weeks ago it was a new solar thermal device capable of converting more of the sun’s energy into efficient heat, now MIT and Madsar Institute engineers are reporting on another innovation that could significantly boost the power output of solar panels. Self cleaning solar panels have been the holy grail of those in regions without a lot of rainfall.
The multi-disciplinary team have developed a self-cleaning “super coating” that prevents the build-up of dust and dirt particles on the surface of solar modules. This is an issue of particular importance in desert regions like Masdar’s home base of Abu Dhabi.
“Dust and dirt are the proverbial kryptonite to a solar panel’s ability to convert sunlight into electricity, drastically reducing a solar cell’s conversion efficiencies. Just four grams of dust per one square metre of a solar cell’s surface can reduce its energy output by 40%,” the team states.
Self cleaning solar panels
Although self-cleaning solar panels aren’t new (conventional rooftop solar panels utilise rainwater to self-clean), the MIT/Masdar researchers say the revolutionary coating provides five key advantages over standard panel technology:
- the ability to self-clean;
- abrasion-resistance;
- self-healing;
- anti-reflection, and
- anti-static properties.
It’s the first time self-healing and anti-static properties have been successfully combined into a spray-on film for solar panels. Consequently, the team says that their breakthrough was optimising all five properties in one coating.
“This is because when one property, such as anti-reflection or self-cleaning, is achieved, then the other property of anti-abrasion will be reduced, or vice-versa. It has been a challenge to fabricate a coating that doesn’t require the sacrifice of one property over the others.”
Solar panel coating repels water and dust
A solar cell coated with the film becomes “super-hydrophobic”. That means water wicks easily from the surface, carrying dirt and grime with it. The film also repels negatively-charged dust particles. Self-healing characteristics repairs scratches on the cells’ surface, allowing more solar energy absorption.
Composed of cheap polymers and clay materials, production of the coating costs roughly USD $2 per kilogram. That makes it a suitable solution for large-scale solar power plants in regions like the United Arab Emirates (UAE). In deserts, keeping panels clean and operational is an expensive proposition due to dry, dusty conditions and scarcity of water.
The group is working on perfecting the new super coating at Masdar Institute’s solar field test facilities in Abu Dhabi.
“Though we are still in the experimental phase of our research, we have already successfully optimized the properties of anti-reflection, self-cleaning and abrasion-resistance. We are now in the process of perfecting the self-healing and anti-static properties and expect to have all properties optimized within a year,” the team says.
