An ENG-bred startup aims to help solar fulfill its promise
By Patrick L. Kennedy
A growing source of renewable energy, solar power is a vital part of our sustainable future. But in many regions, solar infrastructure comes with its own carbon footprint. Vast arrays of solar panels are being erected in deserts around the globe—which makes sense: After all, deserts get plenty of sun, and they boast lots of room for rows of the large structures.
Unfortunately, deserts also have lots of sand blowing around. That sand can cover the panels, which of course are supposed to be kept clear in order to let in all that sunlight. So, maintenance crews must regularly drive “water buffalo” tanker trucks out to the solar plants—traveling many miles in, typically, fossil-fuel-powered vehicles. There, they power-wash the panels—using gallons of water, in arid regions that can ill afford it.
In India, where Annie Rabi Bernard (ENG’15,’20) grew up, that water is often diverted from farms and rural residents who still lack running water. “You would see trucks bringing in water to clean these panels, while literally on the other side of the road you’d see women and children walking towards wells to get water,” Bernard recalls. “It’s almost criminal to deprive a society of affordable water.”
A solar solution
But to Bernard, the solution to this disconnect isn’t to shut down the solar fields. Rather, it’s to find a smarter way to keep them clean.
At Boston University, working with Ryan Eriksen (CAS’10, ENG’15) in the lab of Research Professor Malay Mazumder (ECE, MSE), that’s just what Bernard did. The team developed a system whereby a small amount of static electricity pushes dust and sand from the surface of a solar panel. It takes less than two minutes, once a day, so the electricity used is “minimal to negligible,” Bernard says. She and Eriksen estimate their technology can save around 4 billion gallons of water per year—and that’s just on the solar panels that are installed already.
In 2020, with the help of the BU Office of Technology Development, Bernard and Eriksen co-founded Sol Clarity to bring their technology to market. The startup’s slogan is: “Dust settles; we don’t.” With Eriksen as CEO and Bernard as CTO, they’ve joined forces with Malav Sukhadia (Questrom’21) as head of growth and finance. Sol Clarity has garnered pre-seed funding from venture capitalists and landed grants from the Massachusetts Clean Energy Center, a state economic development agency.
Operating out of their headquarters at Greentown Labs in Somerville, Mass., Sol Clarity started out building their own prototypes by hand. Now they’re contracting with manufacturers to produce one-by-two-meter panels to meet a growing demand from multinational utilities for pilot installations.
Most dust gone in half a minute
Sol Clarity’s product, a transparent electrodynamic screen (EDS), can be applied as overlay sheets onto existing solar panels or integrated into the manufacturing of new panels. The technology works by sending pulsed voltage through rows of electrodes. The electrodes rapidly reverse polarities, alternately repelling and attracting dust particles so that the particles jump from one electrode to the next, until they reach the end of a row and are ejected. This all happens incredibly quickly. “Usually, within 30 to 40 seconds, you’ll see more than 90 percent of the dust being removed,” says Bernard, and in less than two minutes the panel is completely clear.
Last December, Sol Clarity installed a dozen EDS-enabled panels at a site in Massachusetts—so far the world’s largest deployment of this pioneering technology, according to U.S. Glass Magazine. As they add sites around the world, the company plans to collect more data on the technology’s benefits, and continue to grow, ultimately serving the large-scale arrays in arid regions in California, Chile, Saudi Arabia, India, and elsewhere.
While Eriksen and Bernard have worked hard to hit their milestones, they credit a combination of people and experiences at BU with helping them to launch this effort—starting with their collaboration in Mazumder’s lab.
“The fact that I joined as an electrical engineer, and Ryan came in with a materials background—that by itself was super helpful,” says Bernard. “And I found a similar advantage in having Professor Mazumder as my advisor, because he represented both the materials and the ECE side.”
Growing business savvy
Both alumni say they were trained well by Rana Gupta, then-director of BU’s technology development office. Through an accelerator program run by Gupta, they met with scores of solar plant owners to learn about their needs and float the EDS concept. After all the work she put into the technology, Bernard at first found it hard to keep her composure when solar industry pros said they weren’t interested.
“We learned it doesn’t matter if you have the coolest technology,” Bernard says.
“We had to start thinking about the return-on-investment, which we didn’t always consider as engineers,” says Eriksen. That’s just one area where Sukhadia, the Questrom alum, has been integral to the company, Eriksen adds.
“If Malav didn’t bring his MBA skills into the company, we wouldn’t have made such progress,” agrees Bernard.
Sukhadia was also an excellent fit for Sol Clarity in that he had an engineering background before earning his MBA at BU, and he is also a native of India. Like Bernard, he can never forget seeing mothers waiting in line for rationed water in rural areas.
Even without those firsthand observations, Eriksen shares his startup teammates’ motivations. “I’ve always wanted to have a positive impact on society,” he says. “With Sol Clarity, we’re trying to revolutionize the solar space with a disruptive solar panel cleaning technology. If we succeed, we can make renewable energy easier, more affordable, and more effective, and then we’re having that positive impact.”
Photography by Michael D. Spencer. This story originally appeared in the fall 2024 issue of ENGineer magazine.