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Staff Biographies

Learn more about the expertise and technical skills of NREL's concentrating solar power research team and staff by reading our short biographies:

Photo of Nate Blair

Nate Blair—Group Manager, Data Analysis and Visualization
M.B.A., University of Wisconsin-Madison School of Business
M.S. Mechanical Engineering, University of Wisconsin-Madison Solar Energy Laboratory
B.A. Physics, Gustavus Adolphus College

Read Nate's biography on NREL's Energy Analysis Office Web site.

Contact information:, 303-384-7426

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Photo of Dan Blake

Daniel M. Blake—Emeritus Principal Scientist and Subcontractor
Ph.D. Chemistry, Washington State University
B.S. Chemistry, Colorado State University

Dan was hired at SERI/NREL in 1986. Current work is on developing heat-transfer fluids and innovative thermal storage materials. He has led work on developing materials for solar applications; materials and design concepts for large-area solar reactors for solar photoelectrochemical and biological hydrogen production from water; and developing photocatalytic systems for removing chemical and biological contaminants from air and water. In 1992, the photocatalytic team won an R&D 100 award for a Solar Detoxification process. He also led work on deactivating biological agents using liquid desiccant technology. In 2006, Dan received the Hubbard Award at NREL for his sustained, clearly defined, high-level research contributions, and true leadership and initiative in furthering the image of NREL. Dan has assisted the DOE Nuclear Hydrogen Initiative with thermal cycle evaluation and monitoring technical progress in thermal cycle R&D and monitored work on a pilot-scale test of a new production process for solar-grade silicon, which was a joint US-Russian project funded by DOE. He continues to work with the Concentrating Solar Program on innovative methods for thermal energy storage and new heat transfer fluids. Prior to joining NREL, Dan was a Senior Scientist and Group Manager for ARCO Metals Company in Tucson, AZ. There, he worked on processes to improve alumina properties for aluminum production. Prior to that he was Professor of Chemistry at The University of Texas at Arlington, where he taught inorganic chemistry and carried out research on the synthesis and thermochemistry of compounds of the platinum group metals. He has been awarded three U.S. patents—a commercial process for high-purity alumina production, photocatalytic reactor design, and air-cleaning systems. He has published more than 80 papers and book chapters. And he has made over 100 presentations at conferences, symposia, and professional meetings.

Contact information:, 303-384-7882

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Photo of Victor Castillo

Victor Castillo—Research Technician IV
A.S., Electronics Engineering Technology

Victor joined NREL in 2011. His current work is in the design, fabrication, and assembly of prototype test facilities. Prior to NREL, he spent several years in the research and development of fuel cell technology.

Contact information:, 303-384-7476

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Photo of Greg Glatzmaier

Greg Glatzmaier—Senior Engineer II
Ph.D. Chemical Engineering, University of Colorado
B.A. Chemistry, St. Johns University

Greg originally joined NREL in 1987 and worked in the Solar Thermal Program until 1997. During this time, he demonstrated a new concentrating solar technology and initiated a multi-year collaboration with Coors Ceramics Company to develop a high-temperature materials synthesis process. He received three patents for this work.

From 1997 to 2007, Greg operated an R&D small business in which he developed fluid compressor designs and feedback control mechanisms for space applications. This work was funded with several R&D grants from NASA and the U.S. Air Force. He received one patent for this work.

In 2007, Greg rejoined NREL and the CSP team to work on systems analysis, novel heat-transfer fluids, and thermal-storage concepts for concentrating solar power technologies. He currently manages the advanced heat-transfer fluids and thermal-storage work at NREL.

Contact information:, 303-384-7470

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Photo of Judith Gomez

Judith Gomez—Engineer IV
Ph.D. Metallurgical and Materials Engineering, Colorado School of Mines
M.S. Materials Engineering, Simon Bolivar University, Venezuela
B.S. Materials Engineering, Simon Bolivar University, Venezuela

Judith joined the Concentrating Solar Power (CSP) team in 2010. She is developing new formulations of molten salts as thermal energy storage (TES) materials and advanced heat transfer fluids (HTF) for parabolic trough systems. She is also involved in nanofluids research as a state-of-the-art HTF material. Part of her activities include developing protocols for thermal property determinations for TES and HTF. For her Ph.D. work, she developed a new process in molten-salt electrolysis for which a patent application is pending. She currently holds a volunteer appointment as Research Assistant Professor at Colorado School of Mines, where she helps to teach Advanced Materials Thermodynamics and serves as member on graduate theses committees.

Contact information:, 303-275-4290

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Photo of Allison Gray

Allison Gray—Engineer III
M.S. Mechanical Engineering, University of Nevada, Las Vegas
B.S. Mechanical Engineering, University of Nevada, Las Vegas

Allison joined NREL in 2008, working as an engineer in the Concentrating Solar Power group. Before working at NREL, Allison worked on concentrating solar thermal and photovoltaic technologies for 4 years at the University of Nevada, Las Vegas. Her work there included investigating system performance and reliability, data acquisition, and solar resource studies. Her Master's thesis focused on improving the passive cooling system of a high concentrating photovoltaic system using a numerical model and experimental data.

Contact information:, 303-384-7405

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Photo of Matthew Gray

Matthew Gray—Scientist IV
Ph.D. Physics, University of Virginia, Charlottesville, VA
B.A. Physics, Carleton College, Northfield, MN

Matthew joined the Thermal Systems Group at NREL in 2011. He is working with the Advanced Optical Materials team developing improved solar reflectors, solar absorbers, and instruments to characterize their performance. The group is interested in developing and benchmarking materials that form part of the low-cost, high-efficiency, and long-lived concentrating solar power plants of the near future. Matthew came to NREL from the photovoltaic industry where he worked on performance testing, durability, and metrology of flexible CIGS modules. Previously, he had worked as a process engineer covering all aspects of high-speed diode laser fabrication including device design, process development, failure analysis, and performance and lifetime qualification testing. His graduate and postdoctoral work focused on sub-diffraction-limited optical characterization of surface defects in semiconductors and other thin films. Through this work, Matthew has gained expertise in thin-film deposition, material metrology, and optical interactions with surfaces.

Contact information:, 303-275-3917

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Photo of Katelyn Kessinger

Katelyn Kessinger—Undergraduate Intern
B.S. (in progress), Metallurgical and Materials Engineering, Colorado School of Mines

Katelyn joined NREL in June of 2013 as an undergraduate intern. She is a member of the Advanced Materials team, primarily measuring properties such as the reflectance and transmittance of solar reflectors and absorbers. In 2012, she worked as an intern at the Savannah River National Laboratory, assisting with corrosion and extraction work. She is currently considering the possibility of pursuing a Master's in Materials Science.

Contact information:, 303-384-6419

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Photo of Zhiwen Ma

Zhiwen Ma—Senior Engineer I
Ph.D. Mechanical Engineering, Georgia Institute of Technology
M.S. Thermal Engineering, Tsinghua University
B.S. Thermal Engineering, Tsinghua University

Zhiwen joined NREL in 2009 working in the Concentrating Solar Power Group. He has experience in multiple fields, including combustion, fluidization, hydrogen and fuel cells, electronic thermal management and packaging, and gas turbines. He taught in the Department of Engineering Mechanics at Tsinghua University for three years, conducted multiphase flow research, and developed pyrometer techniques for measuring gas turbine temperatures. Since 2001, he was Test and Modeling Engineer in Fuel Cell Energy, and worked on molten carbonate fuel cell performance and life improvement for cost reduction. He was also involved in the Solid State Energy Conversion Alliance (SECA) program, supporting the testing and modeling of solid-oxide fuel cell stacks and system design.

Zhiwen has papers, a book chapter, and a patent published in the areas of fuel cells and thermal fluids. Before joining NREL, he worked for GE Aviation on gas turbine flow and heat-transfer design. He currently works on system analysis, measuring the properties of heat-transfer fluids, and developing thermal-storage concepts for CSP technology.

Contact information:, 303-275-3784

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Photo of Janna Martinek

Janna Martinek—Postdoctoral Researcher
Ph.D. Chemical Engineering, University of Colorado
M.S. Chemical Engineering, University of Colorado
B.S. Chemical Engineering, University of Colorado

Janna Martinek joined NREL in 2012 as a postdoctoral researcher. Her current work involves developing computational models to evaluate the performance of power tower receiver concepts. For her graduate work, Janna developed models coupling radiative transfer with heat transfer, mass transfer, and chemical reaction kinetics in order to analyze the performance and optimize the geometric configuration of a solar receiver used for high-temperature solar-thermal reaction processes.

Contact information:, 303-275-3779

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Photo of Mark Mehos

Mark Mehos—Group Manager/Principal Program Manager
M.S. Mechanical Engineering, University of California at Berkeley
B.S. Mechanical Engineering, University of Colorado

Mark has been with NREL since 1986. He has led the High Temperature Solar Thermal Team at NREL since 1998 and has managed the Concentrating Solar Power (CSP) Program since 2001. The emphasis of NREL's High Temperature Solar Thermal Team is the development of low-cost, high-performance, and high-reliability systems that use concentrated sunlight to generate power, with an emphasis on large multi-megawatt parabolic trough systems and kilowatt-scale concentrating photovoltaic systems. He currently is a participating member of New Mexico Governor Bill Richardson's Concentrating Solar Power Task Force as well as the Solar Task Force for the Western Governors' Association Clean and Diversified Energy Initiative. In addition to managing the CSP program, he has managed and performed technical work within NREL's advanced optical materials, solar photocatalysis, and dish/Stirling research and development activities.

Contact information:, 303-384-7458

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Photo of Ty Neises

Ty Neises—Engineer II
M.S. Mechanical Engineering, University of Wisconsin-Madison
B.S. Mechanical Engineering, University of Wisconsin-Madison

Ty joined the Thermal Systems group at NREL in 2011. His current work involves studying concentrating solar power (CSP) systems and expanding current CSP modeling capabilities. As a graduate student at the University of Wisconsin-Madison Solar Energy Lab, Ty studied the thermal characteristics and performance of photovoltaic (PV) modules and developed a model to predict the temperature of a PV module or array under various mounting configurations.

Contact information:, 303-275-4537

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Photo of Judy C. Netter

Judy C. Netter—Mechanical Engineer III
B.S. Engineering Technology, St. Cloud State University, Minnesota

Judy joined the NREL staff in 1994. Her expertise involves the design, fabrication, and modification of prototype experimental equipment along with the programs and controls. She also has been heavily involved with testing in a wide variety of areas over the years. Prior to joining NREL, she was involved with installing and programming building automation, FLS, and security systems.

Major projects for CSP include the design of a multitude of experiments and test equipment for characterizing solar collectors/concentrators, most recently for parabolic troughs. She has also designed and assisted with tests involving trough receiver heat loss and hydrogen mitigation in trough receivers. Judy is involved in the operation of NREL's High-Flux Solar Furnace and has designed multiple secondary concentrators for the Furnace, along with cooling chambers and the design and fabrication of multiple accelerated weathering chambers for use at the Furnace for testing the degradation of polymer coatings. Other areas of her work have included the condensation of mixed working fluids for geothermal technology; lifetime durability testing of electro-chromic windows, thin films, photovoltaic cells, and polymers; photocatalysis; thermal management of power electronics as it relates to hybrid vehicles; and building technologies.

Contact information:, 303-384-6258

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Photo of Teri Spinuzzi

Teri Spinuzzi—Administrative Assistant

Teri joined the NREL staff in August of 1995. She currently provides administrative support to the Thermal Systems Group within NREL's Electricity, Resources and Building Systems Integration Center. Prior to joining the Thermal Systems Group, she provided administrative support to the Employment Team in Human Resources, the Deployment Programs Office and the Technology Transfer Office. Before coming to NREL, Teri spent many years at the rocky flats plant providing administrative support to various departments, such as Human Resources, Information Services and Industrial Hygiene.

Contact information:, 303-384-7425

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Photo of Robert Tirawat

Robert Tirawat—Research Technician III
B.S. Electrical Engineering Technology, Metropolitan State College

Robert joined NREL in 2008 as a student intern for the Advanced Materials team. He has since graduated and been brought on as a research technician. Robert is helping to develop low-cost, high-performance, and high-reliability systems that use concentrated sunlight to generate power. Recently, Robert has been involved in upgrading a three-chamber vacuum deposition system that will be used to produce solar-selective coatings for testing. In the future, Robert plans to pursue a master's degree in material science at the Colorado School of Mines.

Contact information:, 303-384-6360

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Photo of Craig Turchi

Craig S. Turchi—Senior Engineer II
Ph.D. Chemical Engineering, North Carolina State University
B.S. Chemical Engineering, Texas A&M University

Craig originally joined NREL in 1990 working in the Solar Industrial Program on the detoxification of hazardous waste with solar ultraviolet light. He returned to NREL in 2008 after spending 10 years as a principal investigator and program leader with ADA Technologies, a technology development company in Littleton, CO. While at ADA, Craig served as a principal investigator for projects with the Environmental Protection Agency (EPA), National Institutes of Health (NIH), Department of Defense, DOE, Electric Power Research Institute (EPRI), as well as several private companies. As part of NREL's CSP team, Craig is assisting with system analysis and the development and assessment of heat-transfer fluids and thermal-storage concepts. Craig is the task leader for the CSP Program's Market Transformation activities, which includes technology-enabling issues such as solar resource assessment, cost estimation, land use, and grid integration/transmission.

Contact information:, 303-384-7565

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Photo of Michael Wagner

Michael Wagner—Engineer III
M.S. Mechanical Engineering, University of Wisconsin–Madison
B.S. Mechanical Engineering, University of Wisconsin–Madison

Mike joined the Concentrating Solar Power group at NREL in 2009. His work in the group primarily involves developing simulation capabilities for power-plant modeling. To improve the CSP knowledge base, he is exploring both general technology assessment tools and detailed, plant-specific models. His other activities include active involvement in developing the Solar Advisor Model (SAM) software. Before joining NREL, Mike's research for his Masters degree involved working in the University of Wisconsin–Madison Solar Energy Lab to produce simulation tools for solar power tower technology. He developed an optimization/design tool and detailed, transient system-component models.

Contact information:, 303-384-7430

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Photo of Tim Wendelin

Tim Wendelin—Senior Engineer II
M.S. Physics, Colorado School of Mines
B.S. Physics Engineering, Colorado School of Mines

Tim began work at the Solar Energy Research Institute (SERI) as a student intern in 1981. He worked primarily on thermoelectric devices within the Materials Research group. Ultimately he became involved with thin-film research as applied to reflective surfaces. It was in this field that he completed his graduate thesis. Tim accepted a permanent position at SERI in 1984 working in the Thermal Systems group and has become an expert in optical/thermal modeling and testing of concentrating solar power optical systems. He has authored or coauthored numerous papers on various aspects of concentrating solar power (CSP) technology and holds three patents and two software copyrights. He has developed a variety of optical and thermal test instruments that characterize the performance of various solar concentrator designs. In addition to instrumentation design, he also developed an optical modeling code filling a gap in the tool set used by industry to design solar concentrating systems. These instruments and the optical modeling tool have been used extensively both at the National Renewable Energy Laboratory (NREL, formerly SERI) and by industry to further the deployment and operation of CSP technology. Currently Tim continues to support optical technology development and optical testing of solar concentrating systems at NREL. He is also the technical project manager for several projects at the Solar Technology Acceleration Center (SolarTAC), including a 1.25-MW Thermal Energy Storage Test Facility.

Contact information:, 303-384-7475

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Photo of Guangdong Zhu

Guangdong Zhu—Mechanical Engineer IV
Ph.D. Mechanical Engineering, University of New Mexico
M.S. Thermal Engineering, Xi'an Jiaotong University
B.S. Thermal Engineering, Northeast China Institute of Electric Power Engineering

Guangdong joined the Thermal Systems Group at NREL in 2010 and is working on research and development of CSP technologies. Currently, he serves as the primary operator of the Solar Industrial Mesa Test Area (SIMTA), where optical-efficiency testing for parabolic trough collectors is performed. He is also involved in optical/thermal modeling and economic analysis of solar concentrating systems.

Guangdong has an extensive background in power generation systems, heat-transfer processes, and fluid mechanics. He is also well versed in stress analysis, efficient computing, numerical modeling, and related experimental validation. He has authored or coauthored peer-reviewed papers, reports, and presentations in the areas of multiphase flow, power generation systems, and solar thermal power.

Contact information:, 303-275-4497

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