Solar power has been getting a lot of press recently as a key part of the “green technology” solution to the nation’s energy problems, but less is said about a fundamental limitation of the technology that two BU engineering researchers are working to overcome. Although photovoltaic solar energy has been around for decades, its use is limited, partly because glass-covered solar panels tend to accumulate dust, which reduces the amount of light reaching the silicon cells underneath.
Funded in part by a new award from Boston University’s Office of Technology Development (OTD), a project conducted by Research Professor Malay Mazumder and Professor Mark Horenstein, both of ECE, aims to address this limitation and make solar energy more cost effective and energy efficient.
Horenstein and Mazumder recently won an OTD Ignition Award, which is given to faculty and staff to bridge the gap between government funded research and product development work. The ECE duo is using the $50,000 award to continue development of a cost-effective way to clean solar panels without the use of water.
“When we think of ‘solar energy’ today, we tend to envision one or two solar panels placed on someone’s garage here in New England,” Mazumder said. “But in reality, the long term trend is toward the development of very large solar installations where sunlight is strong and plentiful, like the desert.
“But the unavoidable buildup of dust on solar panels in desert installations decrease their energy-conversion efficiency, and the absence of water precludes washing the panels to clean them.”
The research is a spin-off of a previous NASA-funded project pioneered by Mazumder at the University of Arkansas, Little Rock, prior to joining Boston University in 2007. The project developed technology that cleaned dust from panels of exploration vehicles on dry and dusty Mars.
“One factor that limited the lifetime of the recent Pathfinder missions to Mars was the slow reduction in available solar power caused by dust deposition on the panels,” Mazumder said.
Existing cleaning methods for solar panels are akin to window washers, which are expensive and need water to operate. Horenstein and Mazumder will use lateral waves of electrostatic force to clear dust from the glass surfaces that cover solar panels. A sensor embedded in the panel will detect reduction in solar output and initiate the clearing process to remove the dust.
“The cleaning operation itself will only take about 10 seconds or so, and need be run only every few minutes or hours,” Horenstein said. “It would be like turning on windshield wipers during a light drizzle – it need be done only every so often.”
While the technology to be adapted in Horenstein and Mazumder’s lab has been shown to work, one large obstacle remaining is the development of an inexpensive manufacturing process. While current economic limitations exist, Mazumder believes the government-mandated tax breaks and an infusion of research grants in green technology will make solar energy a huge part of the economy, and a clean energy solution, going forward.
“Global demand for solar energy harvesting is huge,” he said. “The new government is gung ho on these projects, but the manufacturing process is still critical. We need to understand how we can get this done in a less expensive manner.”