Team

The PACT team has a diverse set of expertise and experience.

Leadership
Joshua Stein photo

Joshua S. Stein

Joshua S. Stein is the director of the PACT center and a Senior Scientist at Sandia National Laboratories where he 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 (PVPMC) and represents the United States in the International Energy Agency PVPS Task 13 on PV Performance and Reliability. Dr. Stein received a PhD in Earth Sciences from the University of California, Santa Cruz in 2000, and joined Sandia in 2001. Publications. Pronouns: he, him, his


Laura Schelhas photo

Laura T. Schelhas

Laura T. Schelhas is deputy director of the PACT center and the reliability team lead. She is a research scientist and group manager at the National Renewable Energy Laboratory (NREL). Her current research interests are focused on the intersection between photovoltaic reliability, emerging new technologies, and materials characterization. She is also the executive director of the US-MAP and DuraMAT consortia. Prior to NREL, she served as deputy director of the Applied Energy Division and group leader for the Grid Integration, Systems & Mobility (GISMo) Lab at SLAC National Accelerator Laboratory. Laura received her doctorate in chemistry from UCLA in 2013. Publications. Pronouns: she, her, hers


Bruce King photo

Bruce H. King

Bruce H. King is the Performance lead for the PACT center and a Distinguished Member of Technical Staff at Sandia National Laboratories. He is technical director of Sandia’s Photovoltaic Systems Evaluation Lab (PSEL) and leads R&D projects in PV performance, characterization and reliability. Prior to Sandia, he was R&D director of the Aerosol Jet Print division of Optomec, where he developed additive manufacturing processes and equipment for solar cell production. Dr. King received a PhD in Materials Science from the University of Michigan in 1997 and joined Sandia in 2011.


Ralph Romero photo

Ralph Romero

Dr. Ralph Romero is the Bankability lead for the PACT center. He is Senior Managing Director at Black & Veatch Management Consulting, LLC. He is recognized expert in the independent assessment of novel technologies. Dr. Romero joined Black & Veatch Management Consulting in 2010, and leads the independent assessment of novel technologies practice. He has been the principal investigator in over 180 technology  assessments in the areas of hydrogen, chemical and mechanical energy storage, power conversion systems, photovoltaic cells and modules, mechanical tracking systems and advanced water technologies. He advises domestic and international manufacturers, developers and financial institutions in the areas of technology, manufacturing, product and process design, among others.


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Kailey Wulfert

Kailey Wulfert is the business development partner for the PACT center. Kailey is a Technical Business Development Specialist at Sandia National Laboratories, who has been supporting Sandia’s Renewable Energy and Grid Modernization programs since 2018. She has experience in proposal management, customer relations, marketing/messaging, strategic planning, and event coordination. Kailey holds a B.S. in Population Health and Psychology and M.B.A. with concentrations in Strategic Management/Policy and Human Resources/Organization Behavior, both from the University of New Mexico.

Sandia
Joshua Stein photo

Joshua S. Stein

Joshua S. Stein is the director of the PACT center and a Senior Scientist at Sandia National Laboratories where he 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 (PVPMC) and represents the United States in the International Energy Agency PVPS Task 13 on PV Performance and Reliability. Dr. Stein received a PhD in Earth Sciences from the University of California, Santa Cruz in 2000, and joined Sandia in 2001. Publications. Pronouns: he, him, his


Bruce King photo

Bruce H. King

Bruce H. King is the Performance lead for the PACT center and a Distinguished Member of Technical Staff at Sandia National Laboratories. He is technical director of Sandia’s Photovoltaic Systems Evaluation Lab (PSEL) and leads R&D projects in PV performance, characterization and reliability. Prior to Sandia, he was R&D director of the Aerosol Jet Print division of Optomec, where he developed additive manufacturing processes and equipment for solar cell production. Dr. King received a PhD in Materials Science from the University of Michigan in 1997 and joined Sandia in 2011.


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Jennifer L. Braid

Jennifer L. Braid is a Senior Member of Technical Staff at Sandia National Laboratories where her current research efforts include PV performance modeling and simulation, advanced imaging and automated image processing for PV modules, developing system performance metrics from time-series data, and contributing to open-source software packages for the PV community. Dr. Braid earned BS degrees in Physics and Mathematics from Ohio University, an MS in Physics from the Ohio State University, and her PhD in Physics from the Colorado School of Mines. Publications, Pronouns: she, her, hers


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Marios Theristis

Marios Theristis is a Senior Member of Technical Staff at Sandia National Laboratories. His research interests include the PV performance modeling and monitoring, reliability, degradation, failure diagnostics/prognostics, and data analytics. Prior to joining the Sandia National Laboratories, he was at the University of Cyprus, Cyprus (2016-2019), the University of Jaén, Spain (2016), Fraunhofer CSE, USA (2015) and NCSR "Demokritos", Greece (2010-2011). Marios received his Dipl.-Ing. in Electrical and Computer Engineering from Democritus University of Thrace, Greece (2011) and his PhD from Heriot-Watt University, UK (2016).


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Angelique M. Montgomery

Angelique M. Montgomery is a postdoc at Sandia National Laboratories. Her research interests include the design, fabrication and characterization of novel photovoltaic and photonic devices and materials for renewable and sustainable energy. Her past experience includes the fabrication of thin film solar cells, material synthesis, new material design and nanoscale characterization of ferroelectric/multiferroics devices. Dr. Montgomery received a PhD in Material Science from the University of Alabama in 2019 and joined Sandia in 2021.


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Kailey Wulfert

Kailey Wulfert is the business development partner for the PACT center. Kailey is a Technical Business Development Specialist at Sandia National Laboratories, who has been supporting Sandia’s Renewable Energy and Grid Modernization programs since 2018. She has experience in proposal management, customer relations, marketing/messaging, strategic planning, and event coordination. Kailey holds a B.S. in Population Health and Psychology and M.B.A. with concentrations in Strategic Management/Policy and Human Resources/Organization Behavior, both from the University of New Mexico.

NREL
Laura Schelhas photo

Laura T. Schelhas

Laura T. Schelhas is deputy director of the PACT center and the reliability team lead. She is a research scientist and group manager at the National Renewable Energy Laboratory (NREL). Her current research interests are focused on the intersection between photovoltaic reliability, emerging new technologies, and materials characterization. She is also the executive director of the US-MAP and DuraMAT consortia. Prior to NREL, she served as deputy director of the Applied Energy Division and group leader for the Grid Integration, Systems & Mobility (GISMo) Lab at SLAC National Accelerator Laboratory. Laura received her doctorate in chemistry from UCLA in 2013. Publications. Pronouns: she, her, hers


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Joseph Berry

Joseph J. Berry is a Senior Research Fellow at the National Renewable Energy Laboratory (NREL) and the perovskite technologies team lead.  He is also the Director of the US-MAP consortium and a Fellow at the Renewable and Sustainable Energy Institute (RASIE).  His research interest span both basic and applied work across multiple classes of semiconductors with a focus on the functional heterointerfaces between them.  Joseph received his doctorate in Physics from The Pennsylvania State University in 2001. Publications. Pronouns: he, him, his



February 02, 2017 - NREL Scientist Ingrid Repins.  (Photo by Dennis Schroeder / NREL)

Ingrid Repins

Dr. Repins is a research fellow active in the Photovoltaics Reliability group at NREL. She has worked for more than 20 years in photovoltaics, including reliability, accelerated testing, standards, device processing, characterization, and manufacturing. She brings an in-depth understanding of materials science and device physics to high-impact questions about reliability. Prior to joining NREL in 2007, Dr. Repins performed research and manufacturing support in the private sector. Dr. Repins received her M.S. and Ph.D. in Physics from Colorado State University, and her B.S. in Physics from Stanford University.


May 23, 2017 - NREL staff Scientist Timothy J. Silverman.   (Photo by Dennis Schroeder / NREL)

Timothy Silverman

Dr. Silverman studies photovoltaic modules and systems, including lab and field performance characterization; failure analysis and accelerated testing; computer simulation of field and accelerated degradation; and diagnostic imaging.and strategic analysis. He won the government’s highest early-career award, the Presidential Early Career Award for Scientists and Engineers, for uncovering the ways in which some shadows can damage solar panels. He received his doctorate in mechanical engineering from the University of Texas at Austin and a B.S. in mechanical engineering from Arizona State University. He has worked at NREL since 2011.


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Dana Kern

Dana B. Kern performs luminescence and thermal imaging of perovskite cells and modules for PACT. She is a research scientist at NREL where she studies semiconductor photophysics and reliability of photovoltaic technologies with various cell and packaging architectures. Dana received her PhD from the University of Washington – Seattle, where she researched fundamentals of excited states and charge transfer in organic solar cells.


March 04, 2016- NREL researchers Chris Deline, left, and Mike Deceglie at the Outdoor Test Facility (OTF) at NREL.    (Photo by Dennis Schroeder / NREL)

Michael Deceglie

Michael Deceglie joined NREL in 2013 researching photovoltaic performance and reliability, focusing on stabilization of thin-film modules, thin-film module reliability issues associated with device and illumination nonuniformity, data analytics for PV field data, PV soiling, the impact of cracked cells on module performance, and in-depth case studies of reliability issues in commercially operated PV power plants. Michael received his PhD from Caltech in applied physics in 2013. Michael earned a M.S. at the University of Queensland as a Fulbright Fellow and a B.S. from Dickerson College.


July 10, 2017- NREL researcher Robert White, Scientist.  (Photo by Dennis Schroeder / NREL)
July 10, 2017- NREL researcher Robert White, Scientist. (Photo by Dennis Schroeder / NREL)

Robert White

Robert White is a data scientist supporting the PACT consortium in designing and developing the needed software architectures to archive, analyze, and access PACT datasets. He currently is the senior data scientist for the Materials, Chemistry, and Computational Sciences (MCCS)-Research Operations group at NREL. His current work is focused on facilitating data infrastructure for the DuraMAT consortium and other Energy Material Networks, and providing database architecture, data extraction, and ongoing data operations for the PV Fleets project and the Research Data Infrastructure at NREL. Robert received his master’s in astrophysics from the University of Texas in 1994. Publications.


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Kirsten Perry

Kirsten Perry works as a data scientist at the National Renewable Energy Laboratory in the PV Reliability & System Performance Group, while pursuing an M.S. in computer science from the Georgia Institute of Technology. Kirsten’s research interests include applying machine learning and deep learning techniques to assess photovoltaic field performance data. She currently works as a data engineer and data architect on the PV PACT project. She received B.S. and B.A. degrees in mechanical engineering and mathematics, respectively, from the University of Oklahoma, Norman, OK in 2017.


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Paul Ndione

Paul Ndione is a Research Scientist at the National Renewable Energy Laboratory (NREL). He joined NREL in 2010 to conduct research on oxide semiconductor systems for photovoltaic (PV) applications. Since then, he has been involved in research activities associated with soiling in PV, concentrated solar thermal power, solar water splitting, and power electronics.  He currently oversees activities related to the testing of PV modules and leads projects pertaining to the development and improvement of certification, calibration, and testing of PV devices. Paul received his doctorate from INRS-EMT, University of Quebec.


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Jackson Schall

Jackson Schall is a graduate researcher for the PACT Center. Jackson is a graduate student at the Colorado School of Mines performing his research at the National Renewable Energy Laboratory (NREL). His current focus is on imaging techniques to characterize metastabilities in perovskite solar cells. Prior to NREL, Jackson received his B.S., in physics, from the University of Toledo.


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Nutifafa Yao Doumon

Nutifafa Yao Doumon is a researcher in the Chemistry and Nanoscience Centre at NREL. His research focuses on organic electronics, especially PLEDs and OPVs, and recently perovskite PVs. Nutifafa’s current work involves stability testing; failure modes/mechanisms; chemical characterization of the active layer; and indoor/outdoor testing of perovskite modules. He received PhD and master’s degrees in nanoscience (applied physics) from the University of Groningen-The Netherlands (RuG); master’s degrees in leadership and theoretical physics, respectively from the RuG and African University of Science and Technology, Abuja-Nigeria; and a BSc in physics from the University of Ghana-Legon. 

LANL
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Wanyi Nie

Wanyi Nie is a staff scientist at Center for Integrated Nanotechnology in Los Alamos National Laboratory (LANL). Dr. Nie received a Ph.D. in Physics from Wake Forest University in 2012. She joined LANL in 2013. She is currently leading a team at LANL investigating novel semiconductors and their devices including solar cells, light emitting diodes and detectors.  Publications.


Black & Veatch
Ralph Romero photo

Ralph Romero

Dr. Ralph Romero is the Bankability lead for the PACT center. He is Senior Managing Director at Black & Veatch Management Consulting, LLC. He is recognized expert in the independent assessment of novel technologies. Dr. Romero joined Black & Veatch Management Consulting in 2010, and leads the independent assessment of novel technologies practice. He has been the principal investigator in over 180 technology assessments in the areas of hydrogen, chemical and mechanical energy storage, power conversion systems, photovoltaic cells and modules, mechanical tracking systems and advanced water technologies. He advises domestic and international manufacturers, developers and financial institutions in the areas of technology, manufacturing, product and process design, among others.


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Rob Foree

Mr. Foree has over 10 years of experience in the US energy industry and joined Black & Veatch’s management and consulting business as an analyst in 2013. He has diverse experience in many aspects of the electric power industry, including independent engineering due diligence for generation assets (solar, battery energy storage, wind, oil, natural gas and coal) and independent assessment bankability projects for renewable energy technology. He also has qualified experience in project management, capital prioritization, asset management, operations monitoring and construction monitoring. Mr. Foree possesses strong financial analysis skills, supported by thorough knowledge of financial, economic and accounting principles. He has a B.S. in mechanical engineering and a MBA from the University of Kansas


CFV Labs
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Jim Crimmins

Jim Crimmins is the Chief Executive Officer and a founding Partner of CFV Labs, a leading photovoltaic laboratory in Albuquerque, New Mexico.  CFV works with clients across the PV value chain.  For manufacturers, CFV helps drive innovation and optimization by providing a full range of performance, reliability and certification services for PV modules, trackers and racking systems.   For PV power plant owners, operators and investors, CFV offers a full range of bankability testing services, quality assurance and forensic analysis. Mr. Crimmins received a B.A. in Economics from Yale College in 1983, and an M.S. in Physics from Harvard University in 1987. LinkedIn


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Daniel Zirzow

Daniel Zirzow is the CTO at CFV Labs leads the Performance Testing Group which focuses on PV module and cell performance testing, modeling, and software development. He is an active participant in the IEC standards development community, in particular IEC 61853-2. He received a M.S. in Physics from the University of New Mexico in 2012, and joined CFV in 2016.


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James Richards

James Richards is the VP of Engineering and the head of the Custom Instrumentation Group where he leads the in-house electronics and software development, specializing in PV related measurement equipment. He received a M.S. in Electrical Engineering from the University of New Mexico in 2018.


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Colin Sillerud

Colin Sillerud is Vice President of Engineering at CFV Labs.   He focuses on reliability testing protocols and power plant testing services at CFV.   He led the validation testing for the mechanical stress and UV backsheet degradation legs in the extended reliability test specification, IEC TS 63209-1, and continues to work on multiple other IEC standards efforts. Prior to joining CFV, Colin worked as a researcher at Sandia National Labs where he published research on high-speed micro-gas chromatography, microplasma discharges, and metal organic frameworks.  He has a M.S. in Chemical Engineering from the University of New Mexico.


EPRI
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Cara Libby

Cara Libby is a Principal Technical Leader in Renewable Energy at the Electric Power Research Institute (EPRI). Libby joined EPRI in 2006 and has held multiple positions within the Renewable Energy Generation team. She currently leads development and execution of EPRI’s Environmental Aspects of Solar research portfolio, which broadly addresses environmental issues for large-scale solar projects. She is a subject matter expert in solar photovoltaic (PV) end-of-life management, PV field testing and reliability, and next-generation concentrating solar thermal power (CSP) technologies. She chairs multiple Technical Advisory Committees for DOE projects. Libby is an EPRI Chauncey Award recipient. Libby is a mechanical engineer with a Bachelor’s degree from Johns Hopkins University and a Master’s degree from Stanford University.


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Wayne Li

Dr. Wayne Li is a Principle Technical leader at the Electric Power Research Institute (EPRI). His research interests include improving solar power plant performance, affordability, reliability, and durability, as well as commercialization of advanced PV technologies. Before joining EPRI, Dr. Li was a senior Manager in research and development at First Solar. He earned his Ph.D. in Electrical Engineering from University of Cincinnati, studying biopolymers and organo-lanthanides for opto-electronics applications. His bachelor’s degree is in Material Science and Engineering from Shanghai University.

University of Toledo
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Michael J. Heben

Michael J. Heben is the Helen and Harold McMaster Professor of Photovoltaics in the Department of Physics and Astronomy at The University of Toledo. He is also the Managing Director of UT’s Wright Center for Photovoltaics Innovation and Commercialization (PVIC).  He received a Ph.D. in Chemistry from Caltech in 1990. He was at NREL for 18 years and was a Principal Scientist prior to coming to Toledo in 2008. His research interests include the science, engineering, and deployment of photovoltaics and other energy-related conversion and storage technologies.


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Yanfa Yan

Yanfa Yan has been an Ohio Research Scholar Chair and Distinguish Professor in the Department of Physics and Astronomy at The University of Toledo, since 2011. Previously, he was a Principal Scientist at the National Renewable Energy Laboratory. He earned his Ph. D. in Physics from Wuhan University in 1993. His expertise includes thin-film solar cell fabrication, defect physics of semiconductors, and nanoscale characterization of microstructures, interfaces, and defects in thin-film photovoltaic materials. He is a Fellow of the American Physical Society.


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Zhaoning Song

Zhaoning Song is a Research Assistant Professor at the Wright Center for Photovoltaics Innovation and Commercialization (PVIC), The University of Toledo. He received his B.S degree in Physics from Xiamen University, China, and his Ph. D. degree in Physics from The University of Toledo. His current research focuses on perovskite solar cells, multijunction tandem solar cells, photodetectors, and photoelectrochemical devices. His research interest includes device physics and modeling, nanomaterial synthesis, thin-film optoelectronics, and techno-economic analysis.

University of Washington
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Devin MacKenzie 

Dr. Devin MacKenzie is the Washington Research Foundation Professor of Clean Energy and an Assoc. Prof. of Materials Science and Engineering and Mechanical Engineering at UW.  He is also the Technical Director of the Washington Clean Energy Testbeds, a lab that provides open-access to world-class tools for energy device research, scale-up and characterization. Devin also >17 years of entrepreneurial experience in additive and sustainable manufacturing of electronics. He was formerly the CEO and co-founder of Imprint Energy, a Berkeley spin-out developing printed flexible batteries. Previously, as the CTO of Add-Vision, Inc., Dr. MacKenzie led R&D for roll-to-roll printed OLEDs. Prior to Add-Vision, he led printed Si RF device and product engineering at Kovio, Inc. a Si Valley MIT spin-out. Dr. MacKenzie also co-founded, Plastic Logic, from Cambridge University while a post doc in Physics researching solution-processed PV, OLEDs, and surface-directed assembly. Prior to that he worked at Bell Labs in Murray Hill.  Dr. MacKenzie has been cited >11K times and holds Ph.D, MS, and undergraduate degrees in Materials Science and Engineering from the Univ. of Florida and MIT. 


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Tanka Rana

Tanka Rana is currently a postdoctoral scholar in the Department of Materials Science and Engineering, University of Washington. He received his B. Sc. and M. Sc. in Physics from Tribhuvan University, Nepal. He completed his Ph. D. in semiconductor materials from the Department of Physics, Incheon National University, South Korea. He was then a postdoctoral researcher for three years in photovoltaics laboratory, Korea Institute of Energy Research, South Korea.  Since 2013, he has been devoting himself to research for low-cost high-efficiency solar cells, Initially, chalcogenide based thin film solar cells, and more recently to perovskite photovoltaics cells and modules.