April 1, 2013
“Exploiting Scale Effects to Create Next Generation Photovoltaic Cells and Systems”
Dr. Gregory N. Nielson
Sandia National Laboratories
When: Monday, April 22nd, 2013 at 3:05 p.m.
Where: Warnock 1230
PV cells, modules, and systems need significant advances for solar power to be financially competitive with grid power without subsidies. To accomplish this, we are leveraging the IC, MEMS, LED, and other microsystem technologies and industries to develop PV cells, modules, and systems that exploit beneficial length scale effects. Numerous significant advances in microsystems technologies have occurred since the current dominant PV system concepts (i.e., wafer silicon, thin film, and concentrated PV) were developed in the 1970’s. These micro-technology advances have opened up new options for PV cells, modules, and systems. The microsystem-enabled PV concepts we are exploring take advantage of beneficial scaling effects that occur as the size of solar cells decrease to the sub-mm length scales. These scaling benefits come into play at all system levels (i.e., cell, module, and system) and lead to improved cell performance, better thermal management, improved inverter designs, new form-factors for modules, improved robustness to partial shading, and many others improvements. We have developed both crystalline silicon and III-V micro-scale PV cells and are using 3D integration technologies to allow significant fundamental improvements for multi- junction cell architectures. We have interconnected and packaged these cells to demonstrated highly flexible PV modules with a bend radius down to 1 mm and the potential for conversion efficiencies of 20% or more for mobile applications. We have also demonstrated prototype flat-plate (~1 cm thick) micro-concentrator PV modules for commercial and utility scale PV applications that utilize simple, low-cost trackers currently used with flat-plate silicon or thin film modules. This system, enabled by fundamental scaling effects, will provide high power output at costs that are significantly lower than any of the current PV technologies, resulting in solar energy prices that will be cheaper than current retail grid power costs across most of the United States without subsidies.
Gregory N. Nielson is a native of Bountiful, Utah. He attended Utah State University and obtained a B.S. degree in Mechanical Engineering in 1998. He pursued graduate studies at MIT where he received M.S. and Ph.D. degrees in 2000 and 2004, respectively. For his PhD dissertation topic he developed the first fully integrated, wavelength-selective optical MEMS switch. In 2004, he came to Sandia as a Truman Fellow where he pursued new ideas in MEMS switching. Taking advantage of the dynamic behavior of devices, he demonstrated MEMS micromirror switching in 225 ns – an order of magnitude faster than other micromirror devices at the time. In 2006 he became a Senior Member of Technical Staff at Sandia and in 2008 was promoted to Principal Member of Technical Staff. Dr. Nielson currently leads the “Microsystem- enabled Photovoltaic” project at Sandia. This work has been recognized by a variety of awards including a R&D 100 Award, a SPIE Green Photonics Award, and a Federal Laboratory Consortium Award. Dr. Nielson was included in Popular Science Magazine’s “Brilliant 10” young scientists list in 2012. He is an author on more than 40 peer-reviewed technical publications and an inventor on more than 30 patents or patent applications. He is a member of IEEE, ASME, and OSA.