Commuting 2 hours and burning 4 gallons of gas every day can make a Silicon Valley scientist seriously consider his carbon emissions. In 2005, Steffen Jensen, now 36, left Silicon Valley behind to take a new job closer to his Santa Cruz, California, home. But when an opportunity arose last year to join Palo Alto, California–based solar start-up SolFocus, he was forced to reconsider. The new job meant another long commute, but it also meant an opportunity to make a real difference in the sustainable-energy field—far more than he could ever achieve by pedaling.

Founded in November 2005, SolFocus is working to make solar energy cheaper by using thin-film materials that are more expensive—but also more efficient—than silicon. The key to making the company’s triple-junction solar cells affordable is concentrator technology, which focuses sunlight on a small area so that a little of the expensive thin-film solar material goes a long way. Since joining SolFocus, Jensen has been working on the transition from the company’s current model system to full-scale production.

Jensen, who received his Ph.D. in physics from the California Institute of Technology (Caltech) in 2000, is catching up on materials science and other areas in which he has no formal training. He and his team are currently working to improve the optics of their system, which focuses a two-mirrored, cassegrain-type telescope on a highly efficient solar cell. “Today, I focus on getting the photons that come from the sun in the right spot,” he says. As the company’s needs change, he expects to follow the energy, working more on getting the electricity produced by those photons onto the power grid. “I’m probably going to evolve as I move along the path of that photon.”

Early on, Jensen thought he'd follow in his father’s footsteps and become an engineer. He enrolled at California Polytechnic State University, but soon he realized that he preferred the broader, deeper curriculum physics offered to the more applied engineering course. He got his degree and then pursued a Ph.D. in high-energy physics at Caltech, where he helped build an optical pumping system for a target used at an electron accelerator at the Thomas Jefferson National Accelerator Facility in Virginia. But by the time he was done with his doctoral work, high-energy physics was starting to feel a little too confining.


Steffen Jensen

He considered working on medical applications of high-energy physics, but he soon realized that the path to real-world applications was too long. Seeking a faster pace, he followed the dot-com boom to Silicon Valley in 2000, not long before the crash. He joined the telecommunications company SDL, where he worked for a year developing optical amplifiers.

Jensen’s physics had taught him how to approach and analyze technical problems, but his work in industry taught him a new set of skills. “There’s a whole level of relationships that you have to learn how to develop [in industry]: There's people that you buy and sell things from … [and] people in different kinds of disciplines," he says. Jensen brings to the table the ability to recognize and understand problems on a fundamental level, says Jim Sulhoff, his former supervisor at optical-networking company Onetta, where Jensen worked from 2001 to 2005. Sulhoff is now director of engineering at the Naperville, Illinois, office of Scientific-Atlanta, a Cisco company.

Working on solar energy means rising before dawn to catch every ray possible, and working for a start-up takes him well into the evening on most days. But despite the long hours and the long commute, Jensen is confident that he has found his niche. He regrets giving up his bicycle, but he knows it was worth it. "When the SolFocus opportunity came up, it was just so compelling, it was worth the tradeoff to go try to cover the world with solar panels--worth burning 4 gallons of gas again per day."

Sarah Webb has a Ph.D. in bioorganic chemistry. She writes from Brooklyn, New York.

Comments, suggestions? Please send your feedback to our editor.

DOI: 10.1126/science.caredit.a0700020

Sarah Webb writes about science, health, and technology from Chattanooga, Tennessee.

10.1126/science.caredit.a0700020