Blue and gold make green in Silicon Valley

SILICON VALLEY, SOLAR VALLEY: Teresa Trowbridge (B.S.'84 Eng. Physics) with 24 Sanyo HIT solar cell panels on the roof of her Los Altos garage. The high-efficiency HIT cells, installed in 2007, absorb diffuse light better, Trowbridge says, due to a layer of amorphous silicon. The system generates 4.8 kilowatts, powering her home, and in the summer producing an excess that goes into the grid. PHOTO COURTESY TERESA TROWBRIDGESILICON VALLEY, SOLAR VALLEY: Teresa Trowbridge (B.S.'84 Eng. Physics) with 24 Sanyo HIT solar cell panels on the roof of her Los Altos garage. The high-efficiency HIT cells, installed in 2007, absorb diffuse light better, Trowbridge says, due to a layer of amorphous silicon. The system generates 4.8 kilowatts, powering her home, and in the summer producing an excess that goes into the grid. (Photo by Teresa Trowbridge.)
You don't have to own a $109,000 Tesla Roadster to know that clean and green technologies are on the rise in Silicon Valley. Electric car startups like Tesla Motors and solar cell and biofuel innovators are snapping up commercial space, while established companies like Applied Materials are growing their clean energy divisions.

“Over the past six years, clean tech's portion of venture [capital] investments has grown from merely 3 percent to more than 25 percent,” reported the San Jose Mercury News in January. The newspaper went on to pronounce clean and green technologies the next great wave of innovation in Silicon Valley.

It's no surprise to five Berkeley Engineering alumni who work in the up-and-coming sector. “It's about time it happened,” says K.V. Ravi (M.S.'65 MSE), chief technology officer for Crystal Solar Inc., a startup in Santa Clara.

The primary challenge for those who, like Ravi, are working on next-generation solar cells, is to lower the cost of solar panels significantly. Now, most solar cells built into solar panels are made with top-grade—and thus very expensive—silicon, which is sliced into wafers to make up the cells, Ravi explains. The manufacturing process is similar to that used for turning silicon wafers into memory chips and microprocessors in the semiconductor industry. (In fact, in 2006, the solar sector overtook the semiconductor industry in its use of raw silicon.)

Crystal Solar is developing thin silicon wafers that use only 15 percent of the silicon that standard technology uses, lowering costs. “Our objective is to achieve cost parity with current energy sources already on the grid,” Ravi says, referring to coal, oil, natural gas, nuclear power and hydropower. “The best source of energy is out there in the sky,” he adds. “Solar is a wonderful technology because you're doing it for the world. If somebody builds a better computer or cell phone, it's not quite the same thing.”

A materials scientist, Ravi worked in photovoltaics early in his career, then spent 20 years in Silicon Valley's semiconductor industry before helping launch Crystal Solar in mid-2008. His migration from semiconductor to solar work is typical for many in clean tech because of the technical similarities between the two.

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Bret Adams (B.S.'87 ME), director of marketing for Sunnyvale startup Calisolar, joined the company last November after working for several other photovoltaic startups and semiconductor companies. Calisolar, which makes high-performance, low-cost solar cells, distinguishes itself from other solar companies, Adams says, by bringing together several manufacturing steps like silicon purification, ingot, wafering and cell processing and efficiently integrating them under one roof.

“We're able to succeed against market-dominant Chinese, Taiwanese and German competitors because of the good performance of our cells and our ability to control costs,” Adams says. “Once you get the cost right, it's easy to see this industry growing 10, 100 times.” Calisolar expects to hire 150 new employees by the end of this year, he adds.

Teresa Trowbridge (B.S.'84 Eng. Physics) spotted solar's rising star early on, helping Applied Materials launch its solar business group in 2005. She's now director of product management at Skyline Solar, a startup in Mountain View. Like Ravi and Adams, she worked in various electronics and semiconductor positions before moving into clean tech. Skyline, she says, reduces the use of silicon by incorporating aluminum reflectors to focus the light on a smaller piece of silicon.

“My only A+ at Berkeley was in my solar engineering class,” Trowbridge says. “I've always wanted to go solar.” She champions it not only at work but also at her Los Altos home, where she installed 24 solar panels that generate enough energy to power her home.

“Years ago when I was in social settings and people asked me what I did, I told them semiconductors, and that always stopped the conversation,” she adds. “Now I say solar development, and people get excited. They relate to it.”

Scott McHugo (Ph.D.'96 MSE) is a greenie going way back. “In fourth grade, I started the ecology club at school, and I still remember the flag we created,” he says. After 10 years in optoelectronics and medical devices, he's now research manager for the corporate development lab of REC (Renewable Energy Corporation) in Foster City, working on next-generation solar cell modules.

“You put something on the roof that turns the sun into electricity and you don't have to cool the building as much,” he says. “It's intuitive.” McHugo says he tried to break into solar right after graduating from Berkeley, but the industry was too small. “Back then, all the experts were dreaming of a one-gigawatt worldwide capacity. Now one company can do one gigawatt.”

INVENTIVE: David Walther (B.S.'92 ME/MSE, M.S.'97 ME, Ph.D.'98 ME), far right, with fellow executives at the Cobalt Biofuels pilot plant. The Mountain View startup is working on next-generation biofuels. PHOTO COURTESY DAVID WALTHERINVENTIVE: David Walther (B.S.'92 ME/MSE, M.S.'97 ME, Ph.D.'98 ME), far right, with fellow executives at the Cobalt Biofuels pilot plant. The Mountain View startup is working on next-generation biofuels. (Photo by David Walther.)Of course, solar isn't the only green technology revving up the valley. David Walther (B.S.'92 ME/MSE, M.S.'97 ME, Ph.D.'98 ME) is director of engineering at Cobalt Biofuels in Mountain View. He joined in 2007 as the fifth employee at the startup, which is developing methods to make biobutanol (a biofuel like ethanol) from non-foodstock sources of biomass. These include western softwoods and eastern hardwoods as well as mill, pulp and paper plant residues. Before he took the job, Walther was a research engineer at the Berkeley Sensor and Actuator Center, a National Science Foundation research center for microsensors and microactuators.

Why did he join Cobalt? “It was a chance to put ideas into practice,” Walther says. “Plus, my kids were asking what energy will look like in the future, and that really brought the whole need for alternative energies to the forefront of my brain.”

All five alumni say California's clean tech industry faces a tough economic environment right now, buffeted by the global recession, reduced venture capital funding and strong competition from other states, China, Japan and Germany.

But venture capital is starting to flow again, and the region's distinct advantages remain constant: enormous scientific and engineering talent, a flexible workforce able to change hats quickly and a culture of innovation. “The thing that Silicon Valley people thrive on is constant change,” Adams says. “We're always looking to move on to the next thing.”

Yet Berkeley engineers chafe against any suggestion that they'll find the killer green app. “One of the common misperceptions is that there will be a single solution to our energy problems and to climate change,” Walther says. “People want the answer, but there isn't the answer. There are a lot of answers.”