Here Comes the Sun | Shining a Light on Solar Energy

The toys are simple things, set into motion by palm-sized solar cells, and the process of converting sunlight into electricity seems fairly simple, too: Sunlight hits the cells and is absorbed, then separated by a silicon semiconductor into positive and negative charges, creating a batterylike current of electrons that’s shuttled off to power the adjacent contraption. Presto! But Rohatgi, regent’s professor of electrical engineering at Georgia Tech, knows firsthand that the bigger picture of photovoltaic energy is far more complex.

Ajeet Rohatgi
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Ajeet Rohatgi is the director of Georgia Tech’s University Center of Excellence for Photovoltaics Research and Education—the first-ever such center sponsored by the U.S. government—as well as the founder and chief technical officer of Suniva, a manufacturer of solar cells and modules that spun out of his work at the Institute.

 Image by Josh Meister, courtesy of the Georgia Tech Alumni Magazine.

Rohatgi is the director of Georgia Tech’s University Center of Excellence for Photovoltaics Research and Education—the first-ever such center sponsored by the U.S. government—as well as the founder and chief technical officer of Suniva, a manufacturer of solar cells and modules that spun out of his work at the Institute.

These days, his life is defined by photovoltaic research, and he talks about his lab and his  students with an affable, fatherly pride. But his career was once on a much different path. After earning his undergraduate degree in electrical engineering from the Indian Institute of Technology, he received a master’s degree in materials engineering from Virginia Polytechnic Institute and then a PhD in metallurgy and materials science from Lehigh University. It wasn’t until he joined the team at the Westinghouse Research and Development Center, where he became a Westinghouse fellow, that his interest in photovoltaic energy surfaced.

“I had the option to work in solar or work in integrated circuits, [but] my heart was in PV because I felt it was just a great technology to work on—if I can do something, I can make a difference,” he says, sitting behind a spacious wooden desk in his Van Leer building office. “I got into that, and I stayed in this field because I firmly believe in it, that this can have a very positive impact on so many things—the lives of the people, the environment, national security.”

The transformative potential of solar energy is massive, but it’s nowhere close to being effectively harnessed. Sunlight is free and present in unlimited quantities all over the globe, and it can’t be sequestered or fought over like so many other natural resources. And its source should be hanging around for another five billion years or so. “It’s as if somebody created a fusion reactor for you in a safe place, which is far away,” Rohatgi says of the sun. “We know solar electricity has no undesirable impact on the environment you just can’t have a better source. It has been designed for us.”

Rohatgi says that if he could develop a magic box to catch all the sunlight that shines down upon our planet over the course of just one hour, that would be enough to power human life on earth for one year. Taking a more realistic approach, he’s set his sights on producing a solar cell capable of hitting 20 percent—that is, converting 20 percent of the sunlight that falls on the cell surface into usable energy. And in working toward this goal, both at Tech and with Suniva, he is motivated by one mantra: “We will not make high-efficiency cells just for the sake of high efficiency.” The aim is to develop photovoltaic cells that are both maximally efficient and maximally cost-effective, never compromising quality for cost or cost for quality. And that issue of cost is crucial: Solar needs to be competitive with fossil fuel, the current and longstanding energy paradigm, in order to gain any traction in the marketplace.

When Rohatgi started at Westinghouse in 1977, solar was still a fledgling industry. Just a few years before, in 1975, PV energy had been 80 times more expensive than fossil fuel. And in 1985, when he joined the faculty at Tech, there was nothing happening on campus in the way of photovoltaic research. So he decided to build a lab from the ground up—plumbing, equipment, furniture, everything. After years in industry R&D, he was primed to move fast and write aggressive proposals; he recruited students, raised funds and maintained the ever-expanding lab as colleagues gawked at his speed. Sometimes he wondered why he poured so much time and energy into the project when he could just teach his classes and head home at the end of the day. “In some ways you’ve created this elephant that you have to keep feeding,” he says of the lab’s early days. “But if it is done through passion, that’s the main thing.”

His passion is real. Growing up in India, Rohatgi witnessed the impact of electricity—or, more specifically, a lack thereof—on a first-hand basis. In villages and urban centers alike, electric power regularly shuts off for hours at a time. Although most people have figured out ways to work around the outages, Rohatgi knows solar energy would be a massive boon. “In many villages, at nighttime, nobody would work. If you could just put one solar panel on the roof they get three, four hours of electricity,” he says. “I’ve seen villages where there was nothing there, and now they have small industry coming up, just because they got a few additional hours of electricity. It is changing the lives of a lot of people.”

In 1992, Rohatgi’s lab was established as a University Center of Excellence, which required industry engagement in addition to the educational component: companies come to the lab with a problem, and Rohatgi and his students forge a solution.

Meanwhile, the lab’s research continued on its steady course to 20 percent; it hit 17, then 18. Rohatgi was feeling good about the progress. But he was baffled when, in 2006, he was approached by NEA, a venture capital firm that doesn’t exactly make a habit of approaching anyone. The firm wanted to help him start a solar company, to start commercially producing the cells his lab had been working so hard to perfect.

Rohatgi wasn’t sure—he thought he should get to 20 percent before branching out into a business. But the NEA folks said it was the lowest-risk investment they’d ever make: “They said whenever they make investment in companies, sometimes people have never even made a device,” Rohatgi recalls. With 25 years of experience and the world’s best solar panels under his belt, it was easy for the NEA to put their trust in Rohatgi. They told him, “Yes, granted, you’re not at your goal of 20 percent, but … take our money and get there.”

And so, with NEA’s assistance, Rohatgi set about building the team that would launch Suniva in 2007. First up was John Baumstark, now CEO, who came to the company with two decades’ experience in business development and management. “I had the connections, I had the knowledge, I had the technology, I had the vision, but he had this team and the idea about running a company,” Rohatgi says. “It worked out beautifully. The most unique feature of Suniva, the reason it took off so quickly and so fast, is because of this complement—the business team and the technology.”

These days, Rohatgi splits his time between his lab on Tech’s campus and the Suniva offices in Norcross, Ga., a suburb of Atlanta. The lab and Suniva have separate R&D departments, but they share knowledge and talent—and the company’s close relationship with the Institute isn’t its only distinguishing factor. Suniva has pioneered a number of unique technologies, including ion implantation (long used in making chips, but never before in photovoltaics), which improved the efficiency of their cells by one percent and reduced the total number of steps needed to build a cell by two.

That’s huge, and it reflects Rohatgi’s key approach: to improve the quality and cost of his end-products by improving the process by which they are created. Suniva works with what he calls “the DNA of the whole value chain,” improving the efficiency and function of every element involved in the solar cell, from raw material to manufacturing processes. “If I make more efficient solar cells I need less material, and if I make more efficient solar cells I need fewer panels to install,” Rohatgi says. And when solar panels are smaller and more efficient, it means more of them could potentially be installed—on the roof of a factory, say, or a private home—maximizing the amount of energy produced.

Rohatgi thinks his products will be able to hit 20 percent soon, and he predicts the price of solar energy is about to match that of fossil fuel. That means solar may finally start catching on in the broader consumer market. (In some states, thanks largely to government subsidies, it already has. Lower manufacturing costs—aided by lower wages, made possible in part by more lax labor laws—mean it’s closer to happening in China than anywhere else, though there are a few big markets across Europe.)

Rohatgi says he can now make a cell in the lab that could yield up to 23 percent—but if he’s learned one thing since starting Suniva, it’s a reverence for manufacturing. The most stunning advancements in the lab hardly matter if you don’t have the means to replicate them in the real world in a scalable, cost-effective way.

As Rohatgi has been guiding Suniva to produce better solar cells, Suniva has been teaching him about running a successful business. The importance of building a solid team was an early lesson.

“You can have the world’s greatest technology, but if you don’t know how to run the business, it would not go anywhere,” he says. “[You need] the full package, from the scientist to the entrepreneur.”

John Baumstark was the first addition to the Suniva team, but the employee roster has since grown to almost 200, including a number of Rohatgi’s former students and other Tech alumni.

Like Rohatgi, Vijay Yelundur, MSE 97, PhD MSE 03, was impressed by the potential of solar energy at a young age. “When I was around 6 years old, we took a trip to Yellowstone National Park, and I saw someone using a solar cooker. And I became fascinated with the idea of using sunlight to cook food or to produce power,” he remembers.

After wrapping up his undergraduate degree, Yelundur was eyeing grad school and picked the one subject he thought could hold his interest: solar energy. His father ran across an article about Rohatgi’s program in a trade journal and mentioned it to his son, who had no idea there was a solar research group in the basement of Tech’s double-E building. Rohatgi became his thesis adviser, and Yelundur was one of Suniva’s earliest hires, joining the company as a senior engineer. He now serves as manager of the Manufacturing Innovation Center.

Before founding Suniva, Rohatgi says, he was largely divorced from the business side of the solar industry. His education had prepared him for a career in research, sealed off in a lab wrangling samples and hypotheses, so he’s had to play some catch-up. Increasingly, though, his students are suffering no such gap, thanks in part to Institute initiatives like the InVenture Prize, the University-Industry Demonstration Partnership and Enterprise to Empower, all of which foster entrepreneurship as a component of academic research.

“When you don’t know about these things it looks so difficult, but once you know [more, it’s] not that difficult. In fact, once I found out about [the process of starting a business], I was like, ‘Oh, seeing how it’s done, it’s not that complicated,’” Rohatgi says. “There’s a lot of talk about this on campus—that you should train the students from the very start, that it is not very difficult to learn things about business, but that you just have to have a different aptitude. It’s a great thing.”

And, unlike in Yelundur’s day when the PV lab was out of sight and out of mind, the center now occupies a more visible space on campus: the ground floor of the Van Leer building, facing the Tech Green. Rohatgi can take a few steps out of his office and see the 86-kilowatt array of Suniva panels installed on the roof of the state-of-the-art Clough Undergraduate Learning Commons. The panels are set to produce up to 120,000 kWh per year, offsetting more than 80 tons of carbon dioxide. In 1996, just before the Olympic games, Rohatgi and his crew installed what was then the world’s largest solar array on the roof of the Olympic natatorium (now the CRC), but that was different—they were someone else’s panels. He becomes giddy describing what it’s like to see his own work out in the world.

“If you get an opportunity to take something you built … out in the real world, there’s nothing more exciting,” he says. “It was a thrill for me to see the panels, the cells from my factory being installed … because if I am doing it [in the lab], that’s nice, but nobody knows. But now when they’re out in the field, it’s a different sense of pride and satisfaction. It’s really, really nice to even have this opportunity that is right in front of my office. It’s very satisfying.”

This story originally appeared in Volume 88, Issue 2, of the Georgia Tech Alumni Magazine.