Sandia Energy > Programs > Renewable Energy > Photovoltaics > Staff Bios > Cliff Hansen, Ph.D. Cliff Hansen Research and Development, Mathematics Cliff Hansen leads research efforts to improve forecasting power and energy production for photovoltaic systems with the Photovoltaics (PV) and Materials Technology Department at Sandia National Laboratories. He originates methods to translate available laboratory measurements of photovoltaic module properties to plant-scale production modeling, creating, for example, performance models for bifacial PV modules and other new technologies. He leads efforts to foster transparency and reduce costs associated with management and operations of renewable energy systems through open source modeling libraries and development of data exchange standards. He curates PVLib for MATLAB and co-manages pvlib-python (GitHub), co-leads the PV Performance Modeling Collaborative (pvpmc.sandia.gov) (pvpmc.sandia.gov) and co-chairs the Orange Button Working group (Orange Button). Dr. Hansen earned a PhD in Mathematics from The George Washington University.