Sandia Energy > Programs > Renewable Energy > Photovoltaics > Staff Bios > Joshua Stein, Ph.D. Joshua Stein Photovoltaic Energy Systems Scientist Joshua S. Stein is a member of the Photovoltaics and Materials Technology Department at Sandia National Laboratories. He currently leads R&D projects in the areas of photovoltaic module and system performance and reliability, specializing in modeling and analysis of new technologies. He is the founder of the PV Performance Modeling Collaborative and represents the US in the International Energy Agency PVPS Task 13 on PV Performance and Reliability. He has over 200 publications. Dr. Stein received a PhD in Earth Sciences from the University of California, Santa Cruz in 2000, and joined Sandia in 2001.