The questions and answers below have been edited for clarity and concision.
Would you mind providing a brief overview of the history of solar power?
Photovoltaic cells were invented at Bell Laboratories in 1954 in response to the need to power the first satellites that were launched by the United States. They remained a sort of boutique technology for a long time. When I was a graduate student in the 1980s, the world had only one megawatt of total installed solar power—less than we have installed here on the Caltech campus now.
Over time, we saw the telltale signs of exponential growth. With an exponential curve, you don’t notice it growing for a while, but it keeps doubling and doubling and doubling. That was accompanied by an exponential reduction in cost, so the price has dropped by a factor of about 500 since I was a graduate student.
Right now, we are at the hundreds-of-gigawatts scale. At some point next year, the world will actually see its first terawatt of installed solar photovoltaic power.
The Biden administration just announced a plan to produce almost half of the nation’s power from solar by 2050. Do you think that’s possible? And, if so, what technological advances would be needed to get us there?
I think that it’s possible, but it requires a coordinated and concerted effort all the way across the innovation chain, from research and development to deployment and policy. No one thing would allow us to achieve it. There is some concern that today’s technology—silicon photovoltaics—might not be able to scale fast enough, and that is providing the impetus for alternative solar photovoltaics that are currently in R&D [research and development] that could have a lower capital cost for manufacturing.
Historically, the silicon-photovoltaics business has done a very good job of cost reduction, but there may be other technologies on the horizon—thin-film materials—that could further dramatically reduce the material requirements and the capital costs. So, I think it’s going to require a multi-disciplinary, multipronged effort where policy, technology development, manufacturing, innovation, and installation all will have to play a role.
What new emerging technologies in the solar industry are you most excited about right now?
Among mass-manufacturable solar technologies, most exciting is probably the emergence of bi-facial photovoltaic modules—photovoltaic modules that can be illuminated from both sides. If you install them so that they get some …….
