Dry, arid places are obvious locations for large-scale solar plants because there’s plenty of space and plenty of sun. But there’s a problem: Dust and sand that clings to equipment, reducing its efficiency. In places like Saudi Arabia, some solar reflectors–which concentrate heat to produce steam–have to been cleaned twice a week. That seriously increases maintenance costs and raises water issues, because there’s not a lot of water in the desert.
But there might just be an ingenious solution: an electro-static field. A team at Boston University is working on a way to charge dust particles and then push them sideways, so they don’t get in the way. Its transparent “electrodynamic system” is printed on a solar panel or reflector, so it has a sort of force-field around it when it’s turned on. Most creatively, the material has three layers that are activated in phases and create a rippling effect.
“Number one, we want to charge the particle. Number two, we want to lift them up and propel them,” says Malay Mazumder, a Boston University professor of electro-physics. “The dynamic field we apply lifts them up one millimeter and the phases produce a traveling wave that propels the particles, so they are removed from the surface.”
The idea first came from Japan, and Mazumder has developed it for several applications. Between 2001 and 2003, he looked at a way to extract dangerous particles from coal before it’s burned in a power plant. Later, he looked at methods to put charges on drug molecules that treat respiratory diseases so they would go deep into lungs, rather than the stomach where they’re less useful.
The solar project could have the biggest impact, as it might reduce costs for solar operators, especially where they are currently high. It could also make some projects more viable. But there’s still some work to do. Mazumder’s team has only got the fields working with 15-by-15-centimeter panels so far. They need to scale up to at least 1.3 meters to be operational. Plus, they also need to find a material that’s both durable and cost-effective.
“The main barrier is to find materials that we can use outdoors in hot and extreme climates but that are less expensive than the operational cost [of conventional cleaning],” Mazumder says.
He’s confident it can be done, though. He’s got funding from the U.S. Department of Energy and others, as well as help from the large solar company, Abengoa. He hopes the first installations could appear within two to three years.