The Solar Energy Technologies Office (SETO) Lab Call FY2019-21 funding program will enable U.S. national laboratories to make solar electricity more affordable by improving the reliability and durability of photovoltaic (PV) modules, lowering material and processing costs, and increasing PV efficiency. These projects will support PV research and development efforts that could enable utility-scale PV to reach a levelized cost of energy of $0.03 per kilowatt-hour by 2030.
Researchers at the national labs will also conduct market analysis and explore concentrating solar-thermal power and grid integration research as a part of this effort. Learn more about the SETO Lab Call FY19-21 projects.
APPROACH
These projects seek to improve the performance and duration of PV modules, systems, and components. Researchers will develop new technologies and designs to alleviate safety issues, identify or mitigate causes of degradation, and create advanced monitoring and analysis methods, all while reducing material and processing costs. In addition, select projects at the national labs will provide core capability services, like foundational PV cell research and module testing and characterization services, to further support SETO analysis efforts and the solar industry.
OBJECTIVES
The goal of these projects is to support PV research in the United States and contribute research that can increase the efficiency of PV systems and components, reduce the costs of materials, and lower the cost of solar electricity. Newly developed module and cell components, equipment, and monitoring methods will help quantify soiling and enhance the predictability and reliability of PV systems, leading to longer lifetimes in the field and lower operation and maintenance costs.
AWARDEES
Project Name: Performance and Degradation of Monocrystalline Silicon Modules in the Northeast Coastal Climate
Lab: Brookhaven National Laboratory
Location: Upton, NY
Principal Investigator: Alessandra Colli
Project Summary: This project will determine if polycrystalline silicon modules with a known bill of materials (BOM), or list of raw materials and components, deployed in the privately owned commercial PV installation at the Brookhaven National Laboratory campus, can be accessed and analyzed to determine their performance and degradation rates in the Northeast. The project will determine if and what BOM data and initial reference measures are available, and work with the plant’s owners and operators to verify whether possible access to the fielded modules can be granted for testing. The team will write a report that outlines available information about the installation and possible opportunities to access the PV modules for further reliability and degradation studies.
Project Name: Application and Development of Advanced Electro-Optical Characterization for Highly Efficient and Reliable Thin-Film Solar Cells
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Darius Kuciauskas
Project Summary: To determine the sources of power and performance losses in thin-film solar cells, this project will develop new electro-optical PV characterization techniques to look at the interfaces between different layers inside thin-film PV devices. The team will integrate new capabilities with state-of-the-art thin-film PV characterization at the National Renewable Energy Laboratory (NREL) in collaboration with the national lab, industry, and university PV researchers. This collaborative research will enable the development of more efficient and reliable solar cells, with particular emphasis on cadmium telluride PV, a thin-film technology.
Project Name: Cracked-Film Lithography for Low-Cost, High-Performance Metal Grids
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Christopher Muzzillo
Project Summary: This project will research the use of a recently developed, low-cost technique that can create the patterned metal grids that are used to carry current and minimize power losses in the front contact of a solar cell. These techniques can achieve thin grid wires that are merely 50 nanometers (nm) wide, which is three orders of magnitude smaller than the PV industry standard of 50,000 nm for screen-printed contacts. As metal grid performance improves with the use of thinner wires, these low-cost processes could offer new opportunities for next-generation transparent contacts in solar cells and modules. This project will identify and develop the most promising of those processes and evaluate their impact on different PV technologies.
Project Name: End-of-Life Management Analysis and Stakeholder Engagement
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Garvin Heath
Project Summary: As the number of PV installations rises, more modules will age and degrade over time, making it important to learn new ways to safely and properly dispose of PV modules. This project will use two approaches to investigate current and future state-of-the-art techniques to dispose of PV modules. First, the team will bring lessons learned from abroad by engaging with the environmental health and safety task force of the International Energy Agency’s Photovoltaic Power Systems (IEA-PVPS) program, where experts are leading a set of projects on PV module end-of-life management. The team will also analyze topics relevant to end-of-life management from a U.S. perspective. This analysis will help inform manufacturers and other stakeholders on the value of current recycling requirements for PV hardware, as well as on the effectiveness of current efforts to design modules and other equipment for ease of reuse along the PV supply chain.
Project Name: Hybrid Tandem Photovoltaics
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Adele Tamboli
Project Summary: Tandem or multijunction solar cells are able to convert sunlight to electricity with greater efficiency than single junction solar cells by splitting the solar spectrum across sub-cells with different bandgaps. Combining well-established photovoltaic technologies into a single tandem architecture holds promise for dramatically increasing total cell efficiency, but substantial development is needed to address the challenges of scaling hybrid tandems from lab “hero cells” to interconnected large modules. This project seeks to demonstrate high efficiency III-V/silicon tandem solar cells, strings, and modules with a primary focus on benchmarking the three-terminal tandem in relation to state-of-the-art two- and four-terminal configurations. This includes robust device and string simulations, experimental cell and string demonstrations, and reliability testing of cells and novel components.
Project Name: Interdigitated Back Contact Polycrystalline Device
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: David Albin
Project Summary: The basic structure of polycrystalline thin-film devices like cadmium telluride and copper indium gallium selenide have not changed significantly over the past 20 years and consist of at least two discrete active layers to transmit, absorb, and separate photo-generated carriers. Though efforts to optimize layers in these structures have resulted in remarkable improvements, there are new efforts to develop a simpler structure that results in a cheaper and more reliable device. This project will investigate the creation of a device structure that consists of an interdigitated back contact solar cell—a solar cell with two metals—to establish the field necessary to separate electron-hole pairs absorbed by a single, cadmium telluride or selenide absorber that has a long lifetime and doesn’t have window or buffer layers.
Project Name: Monolithically-Integrated Thin-Film Bypass Diodes
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Matt Reese
Project Summary: Bypass diodes can increase resilience in PV modules because they provide alternative paths for the flow of electric current in a solar cell when the current creates too much heat. Diverting the heat prevents damage to the module. Today, bypass diodes must be added after cell fabrication as discrete components housed in a junction box. By carefully choosing growth and scribing order, it may be possible to fabricate thin-film PV modules with bypass diodes already housed within the module. This project will screen candidate architectures to create bypass diodes for thin-film PV that are compatible with current state-of-the-art manufacturing practices. The best candidates will serve as inputs for an electrical simulation to determine what is needed to integrate these diodes into modules. The experimental and simulated results will then be used as a part of a bottom-up cost model to determine their economic viability.
Project Name: Multimode Characterization Approach for Understanding Cell-Level PV Performance and Degradation
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Glenn Teeter
Project Summary: This project will enable the combined use of several complementary measurement techniques to better understand the performance and cell-level reliability of solar PV technologies. The characterization techniques, which include X-ray and ultraviolet photoelectron spectroscopy, will be augmented to consider how factors like high temperatures and exposure to humid air affect PV modules during operation. The research team will also develop new and advanced characterization techniques, such as near-field transport image in 3-D, making it easier to study different parts of the solar cell. The team will create models to establish clear connections between cell performance and solar cell damage under various operating conditions. The new methodology and device models will speed the improvement of efficiency and durability of thin-film and perovskite PV.
Project Name: Novel, Water-Soluble Oxide, Lift-Off Layers for Low-Cost GaAs PV
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Andrew Norman
Project Summary: This project will determine if a novel water-soluble oxide can be used as a base layer for a high-efficiency solar cell. Dissolving the oxide in water would release the solar cell and could enable multiple uses of expensive, single-crystal gallium arsenide (GaAs) or germanium wafers that are currently used for high-efficiency GaAs-based solar cells. Enabling a substrate to be reused many times, and without the need for costly substrate surface reconditioning, could lower the cost of GaAs-based photovoltaics and reduce manufacturing costs.
Project Name: Reducing Uncertainty of Fielded Photovoltaic Performance
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Chris Deline
Project Summary: This project aims to improve the analysis and reporting of PV system field performance to increase confidence in PV system performance among owners and financiers. The team will compare the outdoor performance and degradation rates of conventional module technologies with those of new, high-efficiency silicon technologies. To do this, they will study how exposure to light, water, and other potential sources of degradation affect PV system components, then use that data to develop new models and automated analysis techniques to measure system performance and production shortfalls. The team will then work with industry partners and the Durable Module Materials Consortium’s data hub to enable private investors to upload and evaluate PV production data anonymously.
Project Name: 8-Year Degradation Assessment of Fielded PV in Three Climates
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Daniel Riley
Project Summary: The project will study the rate and possible causes of degradation in PV modules that have been operating in the field for the last eight years. The modules were carefully characterized before deployment, and will be returned to the lab to be analyzed and compared with original measurements. Degradation rates will be quantified using indoor flash testing and outdoor module characterization on the two-axis tracker at Sandia National Laboratories. Visual inspection, infrared, and electroluminescence imaging will be used to identify types of degradation such as cell cracks, delamination, discoloration, and hot spots that can develop after long-term operation in the field. The team will analyze a variety of modules, including mono- and multi-crystalline silicon and cadmium telluride, in three different climates—hot and dry, hot and humid, and cold—and compare them to modules that have not been used in the field.
Project Name: Optimized Bifacial PV Systems
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Joshua Stein
Project Summary: Bifacial PV technology, where both sides of the silicon PV module use sunlight to generate electricity, has the potential to increase PV system outputs by 10% to 30% but is limited to niche applications because of its complex light-collecting dynamics. This project will develop and validate bifacial PV performance models capable of simulating a wide range of system designs. The team will perform design optimization studies on bifacial system types at Sandia National Laboratories and the National Renewable Energy Laboratory and use high-performance computing resources and tools to test and validate these systems. The team will then collaborate with industry to improve standards and best practices in the areas of module and system rating, capacity testing, site prospecting, and safety.
Project Name: Photovoltaic Collaborative to Advance Multi-climate and Performance Research (PVCAMPER)
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Laurie Burnham
Project Summary: As solar manufacturing and deployment becomes increasingly global, accessing comparable high-fidelity PV data from around the world is key to staying ahead of the curve in those areas. This project will make it easier to do that by creating an international research collaborative to establish best practices for the generation and sharing of quality data. Collaborative members will share solar and meteorological data, deploy a common set of technologies and technical approaches, and exchange best practices for monitoring and maintaining emerging technologies. This international collaborative will further the solar community’s understanding of the local factors that influence solar output and longevity, create a platform for cross-climate research, and make a global database available to researchers, manufacturers, developers, and investors.
Project Name: Snow as a Factor in PV Performance and Reliability
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Laurie Burnham
Project Summary: As solar markets expand, there is a growing interest in the impact of snow on the energy productivity of solar PV installations. The buildup of snow and ice on solar panels can restrain electrical output, reduce reliability, and decrease lifetime performance. To better understand and combat these effects, this project will identify and quantify the factors that contribute to snow-induced energy losses and gains using field measurements, snow adhesion force characterization, and modeling. The team will validate the efficiency of technological hardware improvements like advanced coatings and design configurations that can increase annual energy yields and refine existing predictive models to bring greater accuracy to levelized cost of energy (LCOE) calculations. This research will inform product development, improve system designs, and lead to more accurate performance models, helping to boost confidence in LCOE calculations.
Project Name: PVInsight: A Tool Kit for Unsupervised PV System Loss Factor Analysis
Lab: SLAC National Accelerator Laboratory
Location: Menlo Park, CA
Principal Investigator: Sila Kiliccote
Project Summary: Evaluating the performance of a PV system under varying, real-world environmental conditions informs the design of system components and highlights potential causes of degradation. But detailed and accurate performance analysis is not available for smaller residential and commercial systems. Current performance-analysis tests also require that system data be manually collected or verified. In an effort to streamline these processes, this project will develop an open-source tool kit that uses machine learning to automate power-loss-factor estimations for small and medium-size PV systems, thereby drastically reducing the manual work typically needed to identify and quantify them.
PV Core Capability Projects
Project Name: III-V PV Cell Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Myles Steiner
Project Summary: This project will create a path toward cost-effective III-V solar PV cells. The materials used to create these cells offer many advantages, including the potential for high solar cell efficiencies, relatively low sensitivity to changing temperatures, environmental stability, and their light weight and flexibility. This project will research materials and device architectures that can lead to high solar cell efficiencies and develop a low-cost substrate growth technique called hydride vapor-phase epitaxy. The team will also research substrates, including silicon, that are inexpensive or able to be removed and reused will be investigated to create these low-cost III-V solar cells.
Project Name: Advanced Thin-Film PV Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Wyatt Metzger
Project Summary: This work will address core PV cell research to maximize the performance of PV using advanced thin-film copper indium gallium selenide (CIGS) and cadmium telluride (CdTe) technologies. Solar cells just several microns thick—one-tenth the diameter of a human hair—can be made on inexpensive and abundant glass, plastic, or metal foil very quickly with materials such as CdTe and CIGS. This has reduced market costs for solar energy and cleared paths for novel, flexible, lightweight applications, including integrating solar energy into buildings, aircraft, and military applications. This project will advance the fundamental materials science, physics, and chemistry of thin-film PV technologies and seeks to improve solar cell efficiency while further reducing costs.
Project Name: Halide Perovskite Solar Cells PV Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Joseph Berry
Project Summary: This core PV support project will examine critical materials, integration, and device issues required to propel the development of halide perovskite solar cells (HPSC) technologies. This project will use a scientific approach to understand the roadblocks and risks associated with commercializing HPSC technologies, including any challenges to fully scalable manufacturing and long lifetime field operation. This project will focus on stability research to better understand mechanisms that cause degradation and failure in HSPC and develop device stability acceleration factors that can be applied across relevant halide perovskite materials for PV and associated device architectures. This work will be device-centric but have a materials-driven emphasis in order to overcome the efficiency, stability, and scalability challenges preventing HPSC from reaching $.03 per kilowatt-hour by 2030.
Project Name: Hands-On PV Experience Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Adele Tamboli
Project Summary: Hands-On PV Experience (HOPE), is a one-week summer school program held at the National Renewable Energy Laboratory (NREL) each year to train graduate student PV researchers in PV fundamentals, as well as specific cell technologies and techniques in measurement and characterization. The program brings in students from across the United States and their faculty advisors for an in-depth, intensive program that includes hands-on lab experiences in solar cell fabrication and testing. This program aims to train future PV researchers and increase collaboration among the students, faculty, and staff at NREL. HOPE is a selective program with a competitive application process and is limited to approximately 12-15 students each year.
Project Name: PV Cell and Module Performance Testing Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Dean Levi
Project Summary: This core PV support project maintains the National Renewable Energy Laboratory’s PV Cell and Module Performance Laboratory and provides access to PV performance measurements and best practices to U.S. universities, national laboratories, and the Solar Energy Technologies Office. Through its primary reference cell calibrations, this laboratory maintains the PV peak watt rating for the United States. This work assures that U.S. consumers, installers, and PV project developers can have confidence in the power ratings of the PV modules they purchase, enabling a more robust U.S. PV industry. This project also provides a world record of PV performance measurements, which is essential for tracking the progress of PV research and development.
Project Name: PV Reliability Core Capability: R&D to Ensure a Scientific Basis for Qualification Tests and Standards
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Ingrid Repins
Project Summary: This core capability project will perform research and development that leads to science-based tests and standards that can better ensure PV system reliability and quality. The team will design and perform accelerated stress tests on PV products and then correlate the results with successes and failures of PV products in the field. Testing will focus on the module package—including the glass and frame, interconnection devices, and solar cells—and the micro-characterization of both failed and healthy modules to help improve test accuracy and predictive ability. The new tests will help PV system owners better predict long-term safety and energy generation of different products while lowering the cost of PV electricity by extending the lifetime of PV modules.
Project Name: Silicon PV Core Capability
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Paul Stradins
Project Summary: This project will develop silicon-based PV cell research and process engineering. The team will define, approach, and invent next-generation silicon PV materials and device concepts, as well as identify and overcome limitations in efficiency and large-scale production. This work will maintain national laboratory core capabilities and expertise in silicon PV and support workforce training efforts that develop highly qualified PV research professionals. This project also supports research efforts with academia and industry that advances the knowledge base of fundamental materials science, physics, and chemistry of silicon-based PV technologies.
Project Name: PV Performance Modeling and Stakeholder Engagement Core Capability
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Joshua Stein
Project Summary: This core capability project will include the development, implementation, and validation of new performance submodels in the standard set of modeling functions known simply as the PV_LIB Toolbox. These models allow users to simulate PV performance the areas of thermal module behavior, dynamic soiling, and degradation. This project will also support increased collaboration in the international PV community through the PV Performance Modeling Collaborative (PVPMC) and International Energy Agency’s (IEA) Photovoltaic Power Systems (PVPS) Task 13. PVPMC unites academic and industry researchers so they can share the latest ideas on how to accurately model and predict the performance of PV systems in the field. The objective of Task 13 is to improve the reliability of PV systems and subsystems by collecting, analyzing, and disseminating information on technical performance and failures, providing a basis for assessment, and developing sizing recommendations. This project will create and manage an open-source repository of modeling functions and data, help to build and grow the PVPMC, and enable the United States to have a representative in the IEA PVPS Task 13 working group. The results of this project will be shared through the PVPMC website, open-source software, and reports.
Project Name: PV Proving Grounds Core Capability
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Bruce King
Project Summary: This core PV support project will conduct field research to better understand how PV systems function under real-world environmental operating conditions. Short-term research will focus on validating technology improvements designed to increase solar energy harvest, while long-term research will assess PV system reliability and validate computer models for predicting power generation. Researchers will partner with PV module manufacturers and equipment providers to design, install, and test PV systems to meet these goals. The performance data from this project will be made available to the PV industry and U.S. companies will be able to directly interact with the national labs, giving them access to national experts and PV module and system performance assessment tools.
Learn more about SETO’s photovoltaics research and other SETO Lab Call FY19-21 projects.