AFFORDABLE SOLAR ENERGY MAY BE AROUND THE CORNER WITH SUNSHOT PROJECT

A possible breakthrough in solar energy technologies

A team of engineers at the University of California, San Diego has developed a material capable of capturing sunlight and converting 90 percent of it to heat. The nanoparticle-based material can also withstand many years of outdoor exposure as well as temperatures in excess of 700 degrees Celsius, in contrast to the less resistant sunlight absorbing materials currently in use. The team’s efforts were part of the SunShot project, funded by the U.S. Department of Energy as a result of the SunShot Initiative. Started in 2010 by former Energy Secretary Steven P. Chu, the initiative’s goal was cost-efficient solar power production that would be able to compete with other sources of electrical power by 2020.

Sungho Jin, a Mechanical and Aerospace Engineering professor at UC San Diego Jacobs School of Engineering, created the Silicon boride-coatednanoshell material in collaboration with Zhaowei Liu of the department of Electrical and Computer Engineering and Mechanical Engineering professor Renkun Chen. The unique qualities of the material are due to its “multiscale” surface, which is comprised of particles ranging from 10 nanometers to 10 micrometers in size. These structures trap and retain light with improved efficiency, allowing the material to function at higher temperatures while preventing an excess loss of light.

Clean energy in the form of concentrating solar power, or CSP, is responsible for approximately 3.5 gigawatts of electricity produced worldwide. CSP’s energy conversion process mimics the action of generators found in traditional power plants, using molten salt heated by sunlight rather than coal or fossil fuels to turn steam-powered turbines. One benefit of the use of molten salt is its ability to continuously generate steam with specialized thermal storage, even after sunset. The similarity of the two processes would make it possible for coal and fossil-fuel burning power plants to be modified for CSP.

A group of UC San Diego graduate students in materials science and engineering have worked alongside the University of Nevada’s Justin Taekyoung Kim, Bryan VanSaders, and Jaeyun Moon to make the use of this material feasible. Current sunlight absorbing materials degrade quickly, requiring the annual shutdown of CSP plants for the removal of old and application of new coatings to the reflective mirrors, preventing power generation in the meantime. A material lasting many years and enduring higher temperatures would result in more efficient energy conversion, and the UC San Diego research team believes it is on the brink of such technology.