Environmentally benign, renewable solar energy has always had appeal, but that appeal peaked during the 1970s oil crisis, when motorists lined up for hours in hopes of a fill up. Its promise tantalized Richard Swanson, then a young faculty member at Stanford University.
Immediately, he understood the technological problem. Solar cells were simply too inefficient to economically harvest sunlight at its naturally low density. "From an engineering perspective," says Swanson, "the costs were orders of magnitude too high. When you looked at the cost of putting in these large structures [at 10% conversion efficiency, large structures were needed to generate significant power], for the foundation and support structure and installation labor, we found that even if the solar panels were free, you'd never pay back the cost to install."
Although solar power quickly fell out of public view, Swanson remained intrigued by the challenge. He embarked on a materials science research program focused on increasing the minority-carrier lifetime--the time it takes for an electron sparked by absorption of sunlight to fall into an empty space in the crystal's valence shell. The key to a solar cell's efficiency is getting those live electrons to stay free long enough to be collected at the negative terminal, which is doped with positively charged phosphorus as a lure. The longer they can stay in the crystal's conductive band, the better chance of that happening, and the greater the solar cell's efficiency.
When Swanson set out, the average lifetime seemed to be about 6 microseconds, but there was no good test to measure it. The available methods were laborious and time consuming; as a result, this parameter of solar cells was poorly understood. Researchers needed to understand how surface effects and impurities in silicon affected the lifetime. One of Swanson's students, Ron Sinton, developed an instrument that could more easily measure minority-carrier lifetime in bare wafers. Sinton went on to found Sinton Consulting, which manufactures the instruments, now the standard means of measuring minority-carrier lifetime in the photovoltaics industry.
With the help of this instrument, Swanson found ways to use oxidation and hydrogenation to neutralize the defects at the wafer surface and increased the minority-carrier lifetimes by three orders of magnitude. Combined with lenses or mirrors that concentrated sunlight before striking the cell, they developed solar cells with conversion efficiencies as high as 28%, compared to about 10% in the early 1970s.
These advances brought Swanson to a crossroads. "I had the feeling that we had done most of the thesis-worthy work, and the next step was to make the transition out of the lab and into commercialization. I had to decide whether to shift research direction or continue with a commercialization path," he recalls.
Other factors played a role. It was becoming increasingly difficult to get research funding in the semiconductor field. "I could see the day when I would spend all my time writing proposals and no time doing any research, which looked like an unsustainable situation," he says.
He also grew frustrated with academic turnover. Fresh faces and perspectives are stimulating, he says, but "by the time someone got really good and useful, they would leave." He also grew tired of the glacial pace of change in academia. A colleague in search of more lab space would place a quarter under a beaker in someone's lab. A year later, if the quarter was still there, he would argue to the administration that no one was using the lab space.
After some soul searching, Swanson decided to move forward commercially, but the path turned out to be murkier than the research was. He embarked on a self-study program in business-- considering it an intellectual exercise--by reading books and approaching venture capitalists and industry people. For about 3 years, the company remained hypothetical, confined to a file in his office cabinet.
Swanson kept talking to people but without success. He had little trouble getting access to investors but found it difficult to convey the right message. "One famous venture capitalist looked at my business plan and said that it was an excellent treatise on solar energy, but it wasn't a business plan," he recalls. Swanson was also up against history. There were some spectacular failures among early solar-energy companies, he says, creating an undertone of hostility among venture capitalists.
The payoff for his perseverance finally came, and from an unexpected direction. His work had long been funded by the Electric Power Research Institute (EPRI), a nonprofit research company founded by public utilities to carry out and fund electricity-related research and development (R&D). EPRI had decided to hire a business consultant and sent a candidate to talk to Swanson about his company idea. That consultant, Bob Lorenzini, was a veteran of Silicon Valley; in fact, he could be said to be one of its founders. In the early 1970s, he started Siltec, which was one of the first companies to produce the single-crystal silicon ingots that companies such as Intel use to make integrated circuits.
Lorenzini left the meeting impressed with Swanson's technology and its commercial potential. It may have helped that he had a master's degree in materials science from Stanford. Whatever the reason, he decided not to join EPRI; instead, he contacted Swanson and suggested that they go into business together.
Lorenzini proposed a harrowing bargain. He would come onboard as the company's president and chief executive officer, but only if Swanson took a leave of absence from Stanford and promised to leave the university altogether if and when the company received sufficient financing. Swanson swallowed hard and agreed.
Lorenzini's first order of business was to change the company's name. Swanson had chosen Eos Electric Power, after the Greek goddess of the dawn. Lorenzini recast it as SunPower, thinking Eos effete. "And he was right," Swanson says.
Armed with a sharper name, the two attracted an angel investor to set them up with salaries and cash to cover expenses, and they then set out on a tour to attract further investment. Swanson again underestimated the task, expecting to be successful within a few months. Two years later, they landed a venture-capital round of $500,000. Combined with R&D funding from EPRI and the U.S. Department of Energy, the investment allowed them to build a small R&D facility. Swanson resigned from Stanford and became the company's president in 1991.
The company thrived. In 1993, its solar cells powered Honda to a win at the 1993 World Solar Challenge, an annual solar-powered automobile race that runs 3000 kilometers north to south through Australia's outback, from Darwin to Adelaide. More recently, the company's solar cells boosted NASA's solar plane Helios to 30,000 meters--a record altitude for any non-rocket-powered craft, according to Swanson.
His career having spanned both academics and industry, Swanson recalls a pivotal moment in the 1980s when SunPower was no more than an idea. A businessperson told him, "I've spent the last 20 years rounding off my corners on business issues, and you've spent 20 years on technical issues, so we bring a completely different set of experiences to the table," Swanson recalls. He took the lesson to heart. "That was about 20 years ago, so now I've had 20 years of business experience."