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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Flux concentrations on solar dynamic components due to mispointing

Mispointing of the solar dynamic (SD) concentrator designed for use on Space Station Freedom (SSF) causes the optical axis of the concentrator to be nonparallel to the incoming rays from the Sun. This causes solar flux not to be focused into the aperture hole of the receiver and may position the flux on other SSF components. A Rocketdyne analysis has determined the thermal impact of off-axis radiation due to mispointing on elements of the SD module and photovoltaic (PV) arrays. The conclusion was that flux distributions on some of the radiator components, the two-axis gimbal rings, the truss, and the PV arrays could present problems. The OFFSET computer code was used at Lewis Research Center to further investigate these flux distributions incident on components. The Lewis study included distributions for a greater range of mispoint angles than the Rocketdyne study.

Rylicki, Daniel S.↗
NASA NTRS2006

Applications of Self-Powered Modulating Retroreflectors

NASA Glenn Research Center, in partnership with the U.S. Naval Research Laboratory, has developed self-powered modulating retroreflectors (SMRR) for energy efficient, wireless communications applications. A modulating retroreflector (MRR) consists of a multiple quantum well (MQW) optical detector mounted in front of a retroreflector. The SMRR is integrated the MRR with monolithically integrated module (MIM) photovoltaic (PV) receivers to generate power from interrogating laser-light. SMRRs will provide self power capability that would eliminate batteries or other power sources for MRR drive electronics and sensors. The device can be applied to optical communications, wireless sensor and optical ID tags without a battery. Potential applications and preliminary tests based on a lunar surface communications and navigation simulation will be presented.

Chun, Kue↗
DOE OSTI2026

Measuring the Stress Factors for Photovoltaic (PV) Backsheet Degradation

Back sheet failure has resulted in power loss and large-scale recall of photovoltaic modules, resulting in billions of dollars in lost revenue. The light exposure on the backside of a photovoltaic module comes primarily from reflected light which alters the distribution of natural sunlight. Because of this, modelling the backside exposure and duplicating the exposure is much more difficult than modeling the frontside exposure. This project aims to study how various back sheets and junction box materials degrade under different conditions and to develop Python code to help model and predict degradation. The stress factors for back-sheet degradation must be quantified to extrapolate accelerated stress tests to the field. Test samples were placed in the A3, A4, and A5 conditions, as defined in IEC 62788-7-2, to assess the temperature and humidity dependence of ultraviolet (UV) induced degradation. We are utilizing a custom chamber with exposure from 0.5 UV-suns to 5 UV-suns to understand the dependence of degradation on light intensity. A group of samples put in the A3 condition had glass filters with 50% UV cut-offs of 320 nm, 335 nm, and 360 nm to assess the wavelength dependence of UV degradation. All this data is necessary to assess the impact of non-standard UV light exposure. The material evaluation tests include gloss measurements, attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR), UV-visible reflectance/transmittance utilizing a Cary Ci7000 spectrophotometer, and a nano-indenter for surface hardness and modulus measurements. Alongside the experimental work, there is a computational effort using raytracing and Python open-source tools in PVDeg , PVLib, and Bifacial_Radiance. This code will create specific exposure scenarios and enable the evaluation of chamber degradation relative to field degradation. Equation 1 is a strawman equation used to model degradation on the backside of a PV module. We will create simplified code, based on the results of ray-tracing calculations, which uses a view factor approach to provide fast calculations for the most common exposure scenarios.

14 SOLAR ENERGY↗
DOE OSTI2021

Techno-economic Analysis of Novel PV Plant Designs for Extreme Cost Reductions

A techno-economic analysis is underway examining the cost and performance of future large-scale photovoltaic (PV) plant components, including bifacial modules, tandem modules, increased plant voltage architectures, and module-level power electronics. Integration of these components into PV plant designs is compared with current PV technologies based on levelized cost of electricity (LCOE). Baseline models are developed and validated against recorded PV plant performance data. Expected cost and performance data of future PV technologies are incorporated into the baseline models. An evolutionary algorithm is utilized to optimize PV plant configuration, technology combination, and LCOE. This paper focuses on the bifacial module analysis.

14 SOLAR ENERGY↗
DOE OSTI2023

Use of non-contact voltmeter to quantify potential induced degradation in CdTe modules

Potential induced degradation (PID) is a significant reliability issue for photovoltaic modules in the field. Conventionally, to detect the PID-affected modules, all the modules in a string are individually disconnected and measured using I-V (current–voltage) tracers. It is extremely time-consuming, expensive and unsafe (if the module connectors are field aged) approach. In our approach, we aim detecting the PID-affected modules quickly, inexpensively and safely without disconnecting individual modules in the string. In this study, contactless electrostatic voltmeter’s (ESV) strength was explored to detect the PID-affected cadmium telluride (CdTe) modules in a string. These contactless measurements on high-voltage PV strings could make this technique unique and preferable to detect PID-affected modules in a string compared to the I-V curve method. In this work, a CdTe module was stressed for PID using the Aluminum (Al) foil method in a walk-in environmental chamber, which resulted in a reduction of module's peak current (I max ), peak voltage (Vmax), and fill factor (FF), and hence power (Pmax). Outdoor light I-V, EL, and ESV measurements were performed pre- and post-PID to determine the effectiveness of the non-contact ESV technique. Further, the ESV technique successfully detected the change in V max , and hence Pmax, compared to the pre-and post-PID conditions. A difference of less than 2% was observed in the results of the non-contact and non-interruptive method compared to the conventionally used interruptive voltmeter or I-V tracer method. This technique and the test results demonstrate a significant promise to identify poor-performing modules in PV string without disconnection of individual modules in the string.

14 SOLAR ENERGY↗
DOE OSTI2022

Setting the Bar for Device Performance of Photovoltaic Cells and Modules

Cutting-edge photovoltaic (PV) research and development benefits from NREL's world-record accuracy in device performance measurements. NREL is a global leader for PV calibration services to help control manufacturing quality, assess degradation rates, and develop new technologies.

14 SOLAR ENERGY↗
DOE OSTI2021

Employing Weibull Analysis and Weakest Link Theory to Resolve Crystalline Silicon PV Cell Strength Between Bare Cells and Reduced- and Full-Sized Modules

Weibull analysis and weakest link theory are employed to resolve the probability of crystalline silicon PV cell fracture when measured as bare cells and when stressed in reduced- and full-sized modules. Experimental results indicated that the characteristic cell strength is reduced by ~20% once packaged into the laminate of a one-cell module and loaded in four-point flexure (4PF). This experimental observation was shown consistent with a weakest link theory prediction that the strength limiting flaws reside on the surface of the cell's edge. Here, the analysis is ultimately extended to present the equivalent loading of four-cell modules by uniform pressure and 4PF and a uniformly loaded full-sized module and demonstrates that smaller, representative, modules must be loaded to a much higher level than their parent full-sized modules to achieve an equivalent probability for cell fracture.

14 SOLAR ENERGY↗
DOE OSTI2021

Tracking the Sun: Pricing and Design Trends for Distributed Photovoltaic Systems in the United States (2021 Edition) [Slides]

Berkeley Lab’s annual Tracking the Sun report describes trends among grid-connected, distributed solar photovoltaic (PV) systems in the United States. The latest edition of the report focuses on systems installed through year-end 2020, and is based on data from roughly 2.2 million systems, covering 79% of all distributed PV systems installed nationally through 2020. The report describes trends related to project characteristics, including system size, module efficiencies, prevalence of paired PV with storage, use of module-level power electronics, third-party ownership, mounting configurations, panel orientation, and non-residential customer segmentation ownership. Median installed-price trends, including both long-term and more recent temporal trends at the national and state levels, with comparisons to other recent PV cost and pricing benchmarks as well as to prices reported for other countries. Variability in pricing across individual projects based on system size, state, installer, module efficiency, inverter technology, and non-residential customer type. The report also includes an econometric analysis to estimate the effects of individual drivers on installed prices for host-owned residential systems installed in 2020.

14 SOLAR ENERGY↗
NASA NTRS1985

Amorphous silicon photovoltaic modules and test devices design, fabrication and testing

In July of 1984, Hughes and JPL initiated a contract for Hughes to design, fabricate and test 10 thin film Amorphous Silicon (a-Si) photovoltaic power modules. These modules were to be 1 ft x 4 ft in size. They were to be preceded by the delivery of 10 a-Si 4 in. square test devices. This effort is very timely since thin film PV development has progressed to the point where intermediate load power applications are on the horizon. It is important to know if current a-Si submodule design and manufacturing processes yield a product that is compatible with the packaging needed to meet a 20 to 30 year life span expectancy. The term submodule is assigned to an interconnected assembly of 28 a-Si cells deposited on a 1 foot square glass superstrate. These assemblies are equipped with electrical terminations, i.e., copper tabs at the four corners of the inverted submodules. It is these submodules that are to be interconnected and packaged into power modules, as opposed to the interconnected individual crystalline cells packaged into todays PV modules. A discussion of the fabrication methods and results follows.

Vanleeuwen, M.↗
DOE OSTI2020

Transient Weighted Moving-Average Model of Photovoltaic Module Back-Surface Temperature

Accurate modeling of photovoltaic (PV) performance requires the precise calculation of module temperature. Currently, most temperature models rely on steady-state assumptions that do not account for the transient climatic conditions and thermal mass of the module. On the other hand, complex physics-based transient models are computationally expensive and difficult to parameterize. In order to address this, a new approach to transient thermal modeling was developed, in which the steady-state predictions from previous timesteps are weighted and averaged to accurately predict the module temperature at finer time scales. This model is informed by 3-D finite-element analyses, which are used to calculate the effect of wind speed and module unit mass on module temperature. The model, in application, serves as an added filter over existing steady-state models that smooths out erroneous values that are a result of intermittency in solar resource. Validation of this moving-average model has shown that it can improve the overall PV energy performance model accuracy by as much as 0.58% over steady-state models based on mean absolute error improvements and can significantly reduce the variability between the model predictions and measured temperature times series data.

14 SOLAR ENERGY↗
DOE OSTI2025

Q1-2024 Solar Cost Benchmarks

Each year, the U.S. Department of Energy’s (DOE) Solar Energy Technologies Office (SETO) and its national laboratory partners develop cost benchmarks for U.S. solar photovoltaic (PV) systems. These benchmarks track progress toward reducing solar costs and guide R&D priorities. Unlike typical studies that report only $/W, SETO uses intrinsic units (e.g., $/m² for mounting structures) to better capture how technology improvements such as module efficiency would impact system costs. This allows flexible modeling where inputs can vary significantly to assess cost sensitivity. Costs are reported in two ways: Minimum Sustainable Price (MSP): Long term, financially viable price under stable market conditions. Modeled Market Price (MMP): Actual market price, influenced by short term distortions such as tariffs or subsidies. Three national labs collect cost data from industry stakeholders, ensuring no duplication in outreach to stakeholders. Data reflects real transactions (primarily from Q1) and is weighted based on the number of sources per cost element. The PV System Cost Model (PVSCM) divides total installed system cost into eight categories: 1. Module (PV) 2. Inverter 3. Energy Storage System (ESS) 4. Structural BOS (SBOS) 5. Electrical BOS (EBOS) 6. Fieldwork 7. Office work 8. Other (developer/EPC costs) The first five are hardware costs, while the last three are soft costs. Each category includes fixed and variable cost components, where “size” depends on context (e.g., manufacturing capacity for modules vs. system capacity for installation costs). Variable costs are expressed using appropriate intrinsic units. The model reflects the owner’s upfront overnight capital cost, excluding tax credits. Tariffs and subsidies are treated as temporary market distortions affecting MMP but not MSP. PVSCM is implemented in Excel, where cost elements are aggregated into total system cost. Additional sheets handle unit conversions and operation & maintenance (O&M), with O&M costs levelized over the system’s lifetime.

14 SOLAR ENERGY↗
NASA NTRS2004

Russian Activities in Space Photovoltaic Power Modules with Concentrators

Space concentrator modules with point-and line-focus Fresnel lenses and with reflective parabolic troughs have been developed recently at Ioffe Physico-Technical Institute. PV receivers for these modules are based: on the single junction LPE and MOCVD AlGaAs/GaAs solar cells characterized by AM0 efficiencies of 23.5 - 24% at 20 - 50 suns and 24 - 24.75 at 50 - 200 suns; on the mechanically stacked tandem AlGaAs/GaAs-GaSb cells with efficiency of 27 - 28 at 20 - 100 suns. MOCVD AlGaAs/GaAs cells with internal Bragg reflector have shown a higher radiation resistance as compared to a traditional structure. Monolithic two-terminal tandems AlGaAs (top)-GaAs (bottom) for space application and GaSb (top) - InGaAsSb (bottom) for TRV application are under development as well.

Andreev, Vyacheslav M.↗
DOE OSTI2025

Screening Metal Halide Perovskite Solar Modules for Premature Field Failures

Developing metal halide perovskite (MHP) photovoltaic (PV) devices into reliable large-area solar modules could accelerate global solar energy deployment. Many MHP devices are susceptible to degradation under light and elevated temperature (LT). Published research on LT testing is limited at the module level, and LT testing has not yet been developed for qualification testing of commercial PV products. This report assesses whether results of LT testing at moderately elevated temperatures correlate with those of field-tested modules from the same batch. Six batches of samples from four manufacturers are assessed. It is shown that modules with a robust package that can maintain over 80% of their peak efficiency during LT testing at 55 °C for 100 h are more likely to retain over 80% of their peak efficiency during outdoor operation for 10 weeks. This finding is a step towards developing a validated test protocol that could be incorporated into a qualification standard for the commercialization of MHP PV technologies.

14 SOLAR ENERGY↗
DOE OSTI2022

Tracking the Sun: Pricing and Design Trends for Distributed Photovoltaic Systems in the United States, 2022 Edition

Berkeley Lab’s annual Tracking the Sun report describes trends among grid-connected, distributed solar photovoltaic (PV) systems in the United States. The latest edition of the report focuses on systems installed through year-end 2021, and is based on data from roughly 2.5 million systems. New to the report this year is an expanded coverage of paired PV-plus-storage systems, including details on system design and pricing trends. The report describes trends related to: -Project characteristics, including system size, module efficiencies, prevalence of paired PV with storage, use of module-level power electronics, third-party ownership, mounting configurations, panel orientation, and non-residential customer segmentation ownership -Median installed-price trends, both nationally and by state, including preliminary data for first half of 2022 -Variability in pricing according to system size, state, installer, equipment type, and other factors, relying on both descriptive and econometric analysis

14 SOLAR ENERGY↗
DOE OSTI2020

Global Techno-Economic Performance of Bifacial and Tracking Photovoltaic Systems

Although most of the current photovoltaic (PV) system installations use monofacial modules with fixed-tilt mounting structures, bifacial modules, trackers, and the combination of them are also getting more attention as potential candidates to further reduce the PV levelized cost of electricity (LCOE). This work is then the first to present a worldwide analysis on the yield potential and cost-effectiveness of PV farms composed of monofacial fixed-tilt and single/dual (1T/2T) tracker installations, as well as their bifacial counterparts. Our approach starts by estimating the irradiance reaching the front and rear surface of the modules for the different system designs (validated based on data from real PV systems and results from the literature) to estimate their energy production (row-row shading is neglected). Subsequently, the overall system cost during their 25-year lifetime is factored in, and LCOE is obtained. The results reveal that bifacial-1T installations increase energy yield by 35% and reach the lowest LCOE for the majority of the world (93.1% of the land area). Although dual axis trackers achieve the highest energy generation — especially for bifacial modules — their cost is still too high, and are therefore not as cost-effective. Sensitivity analyses based on the Monte Carlo and region sensitivity approach are performed to analyze the impact of input assumptions on the calculated LCOE. These reveal that our conclusions are robust in general but exact configuration to choose depends on specific site conditions. This investigation is not only of interest to the scientific community, but also can be used as a guide for PV installation companies and investors to determine the most suitable technology for a particular location.

14 SOLAR ENERGY↗
DOE OSTI2023

Reliability of tandem solar cells and modules: what's next?

Hybrid tandem photovoltaic (PV) technology development has gained momentum in the last few years. This has been motivated by a need to push module efficiencies beyond what is theoretically capable with single-junction technologies to further accelerate total global PV deployment. Significant advances have been made with multiple material systems achieving tandem efficiencies over 30% in the last decade. All of the highest record efficiencies have been from laboratory-scale devices, with areas of 1 cm2 or less. Interestingly, there are multiple material combinations and terminal configurations that have demonstrated promising results. Despite these high laboratory efficiencies, reasonable service lifetimes (a useful operating lifetime of at least 25 years) are needed for tandems to compete with the levelized cost of energy (LCOE) of traditional single junction PV technologies. Existing commercial Si PV products have demonstrated performance in the field with an average of less than 1% relative annual degradation in module and system performance, and many manufacturers now provide 30 year warranties on their products.

14 SOLAR ENERGY↗
DOE OSTI2020

PV Storm Hardening Costs

While solar arrays often survive severe weather events, systems are occasionally compromised and left unable to provide power. For PV systems to act as resilient power providers, they must remain operational. Building a system that is more likely to survive a storm comes at a cost, though. Previous efforts have identified various system measures and practices that can increase the likelihood of a PV system surviving a severe weather event. But what is the cost premium for a storm hardened PV system? This report provides initial estimates for the up-front cost premiums for various methods of storm hardening PV systems.

14 SOLAR ENERGY↗