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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

BACKFLIP: Identification of Materials and Changes Upon Aging of Emerging Fluoropolymer-Free and Industry-Benchmark PV Backsheets

Extending lifetimes of photovoltaic (PV) modules and decreasing manufacturing and decommissioning costs are motivating research of novel PV module backsheet materials. Backsheet integrity is critical to the safety and performance of a PV module, however, the polymeric materials are often vulnerable to environmental degradation. The long-term durability of emerging polyolefin (PO) materials is being examined to inform regarding the possible replacement of laminated backsheets containing polyethylene terephthalate (PET) cores and fluoropolymer protective inner/outer layers. This study compares traditional PET-based backsheets with novel, co-extruded, and recyclable PO-based backsheets after being subjected to hygrometric and UV photolytic accelerated weathering. A large set of characterization methods will compare physical, chemical, structural, mechanical, and insulating properties of these backsheets and the resulting mini-module (MiMo) PV performances. The study of chemical composition, glass- and phase-transition temperatures, degree of crystallinity, and crystalline structure are described here.

mini-module↗
DOE OSTI2020

Data-Driven Day-Ahead PV Estimation Using Autoencoder-LSTM and Persistence Model

Inherent variability in photovoltaic (PV) and associated impacts on power systems is a challenging problem for both the PV owners and the grid operators. Existing statistical and machine learning algorithms typically work well for weather conditions similar to historical data. Furthermore, uncertain weather conditions pose a great challenge to the estimation accuracy of the estimation models. With the enhanced integration of intelligent electronic devices and the realization of associated automation in the power grid, renewable energy data is becoming more accessible, which can be utilized by deep learning models and improve the PV power generation estimation accuracy. In this paper, a hybrid deep learning model driven by external weather data is proposed to do day-ahead PV output forecasting at 15-minute-interval. The proposed model is motivated by the recent advancement of Long-Short-Term-Memory (LSTM) networks and AutoEncoder (AE), which estimates uncertainties in sequence while making the prediction for complex weather conditions. Meanwhile, the persistence model (PM) is used to predict continuous sunny weather conditions. The forecasting result is validated with data from multiple locations

42 ENGINEERING↗
DOE OSTI2012

Pyranometers and Reference Cells: Part 2: What Makes the Most Sense for PV Power Plants?

As described in Part 1 of this two-part series, thermopile pyranometers and photovoltaic (PV) reference cells can both be used to measure irradiance; however, there are subtle differences between the data that are obtained. This two-part article explores some implications of uncertainty and subtleties of accurately measuring PV efficiency in the field. Part 2 of the series shows how reference cells can be used to more confidently predict PV performance, but how this could best be accomplished if historic irradiance data could be available in PV-technology-specific formats.

14 SOLAR ENERGY↗
DOE OSTI2013

Feasibility Study of Economics and Performance of Solar PV at the Atlas Industrial Park in Duluth, Minnesota - A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America’s Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

The U.S. Environmental Protection Agency (EPA) Region 5, in accordance with the RE-Powering America's Land initiative, selected the Atlas Industrial Park in Duluth, Minnesota, for a feasibility study of renewable energy production. The EPA provided funding to the National Renewable Energy Laboratory (NREL) to support a feasibility study of solar renewable energy generation at the Atlas Industrial Park. NREL provided technical assistance for this project but did not assess environmental conditions at the site beyond those related to the performance of a photovoltaic (PV) system. The purpose of this study is to assess the site for a possible PV installation and estimate the cost, performance, and site impacts of different PV configurations. In addition, the study evaluates financing options that could assist in the implementation of a PV system at the site.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Human Health Risk Assessment Methods for PV, Part 1: Fire Risks

The photovoltaic (PV) industry has experienced rapid growth in recent years due in part to the development of public policies to address climate change and energy security. Some industry stakeholders have expressed concerns regarding potential human inhalation exposure to hazardous materials should a PV module array be exposed to fire, particularly in a residential or commercial rooftop application. To evaluate these concerns, fire hazard analysis methods are presented that can estimate emissions that may occur when PV modules (hereafter mostly referred to simply as 'modules') are exposed to fire, estimate the associated chemical concentrations in ambient air downwind from the fire, and finally compare these exposure-point concentrations to health-protective screening levels. Specifically, this report presents an analysis of potential human health impacts associated with chemical release from modules during a building fire for three PV technologies, focusing on airborne release of the highest-prioritized chemical element for each: Pb content in crystalline-silicon (c-Si) modules, Cd content in thin film cadmium telluride (CdTe) modules, and Se content in thin film copper indium selenide (CIS) modules. The intent of this analysis is to demonstrate the application of the proposed methods for modules exposed to fire in a quantitative yet illustrative manner. In particular, this report quantifies what are expected to be the worst-case potential health impacts over a wide range of possible conditions, including building/fire size, downwind receptor location, exposure duration, and meteorological conditions, utilizing a Gaussian plume modeling approach that is typically used in regulatory contexts.

14 SOLAR ENERGY↗
DOE OSTI2021

Photovoltaic (PV) Module Technologies: 2020 Benchmark Costs and Technology Evolution Framework Results

This report benchmarks 2020 PV module minimum sustainable price (MSP) via bottom-up manufacturing cost analysis, for established PV technologies in mass production, including crystalline silicon, cadmium telluride (CdTe), and copper indium gallium (di)selenide. We provide technology roadmaps to additional MSP reductions for these PV technologies. Separately, we consider III-V and perovskite PV technologies which are currently in small-scale or pilot production. Finally, this report uses a technology evolution framework (TEF) to analyze drivers of levelized cost of energy reductions, including installed system cost - which is heavily influenced by module price - as well as service life and annual energy yield.

14 SOLAR ENERGY↗
DOE OSTI2022

Application of Manufacturing Quality Management Principles to PV System Installations

To help SETO/DOE achieve its goals, the IBTS team proposed a project addressing system reliability by improving installation standards and quality management. The proposed approach was designed to help achieve measurable reductions in installation defect density and improvements in the performance of PV systems by optimizing design and installation of residential and commercial PV systems. This approach addressed the soft costs associated with installations and quality management. The project demonstrated improved system reliability and reduced PV system installation costs. The software developed improved operations, decreased risk, and increased the overall value of PV systems across their lifecycle. The project used several data collection methods, including extensive industry surveys, face-to-face high-level interviews at industry conferences, stakeholder teleconferences, and in-depth interviews conducted by IBTS staff. Results from the research found the industry needs a uniform assessment method for national providers to be more efficient; the software should support both code officials and installers; most industry stakeholders would find value in a centralized software system that allows them to collect, report, and review information on in-process and completed solar installations; and mobile solutions that bridge existing knowledge gaps with inspectors and integrate with existing methodologies (such as permitting software) are of great value. The software solution developed is web-based, allowing for national access, and is built on a Google Firebase platform that can handle significant users and data. It can be used onsite or remotely, allowing for code compliance to continue despite ongoing pandemic related delays or shutdowns for local economies. The information provided by the software tool allows users to uniformly assess a system for compliance and use that aggregated data to identify training topics or create internal process designed to improving issues and reducing occurrence. This solution has multiple benefits in managing quality at time of use and promoting an increase in future safety and quality through education. Perhaps most importantly, this software increases public safety by ensuring compliance of installed systems and allows for local AHJs to remotely engage specialized and qualified solar specific expertise for oversite of the installation in their jurisdictions. Data analysis provides the quality feedback loop identifying the root cause of failure and drives installation practices to improve through training and education, resulting in systems with higher performance, greater reliability, and reduced operations and maintenance costs. With the successful completion of this project, the industry can expect reduced soft costs and increased performance and safety and will ultimately benefit from longer performing systems that cost less to operate.

14 SOLAR ENERGY↗
DOE OSTI2022

Evaluation of Adaptive Volt-VAR to Mitigate PV Impacts [Slides]

Distributed generation (DG) sources like photovoltaic (PV) systems with advanced inverters are able to perform grid-support functions, like autonomous Volt-VAR that attempts to mitigate voltage issues by injecting or consuming reactive power. However, the Volt-VAR function operates with VAR priority, meaning real power may be curtailed to provide additional reactive power support. Since some locations on the grid may be more prone to higher voltages than others, PV systems installed at those locations may be forced to curtail more power, adversely impacting the value of that PV system. Adaptive Volt-VAR (AVV) could be implemented as an alternative, whereby the Volt-VAR reference voltage changes over time, but this functionality has not been well-explored in the literature. In this work, the potential benefits and grid impacts of AVV were investigated using yearlong quasi-static time-series (QSTS) simulations. After testing a variety of allowable AVV settings, we found that even with aggressive settings AVV resulted in <0.01% real power curtailment and significantly reduced the reactive power support required from the PV inverter compared to conventional Volt-VAR but did not provide much mitigation for extreme voltage conditions. The reactive power support provided by AVV was injected to oppose large deviations in voltage (in either direction), indicating that it could be useful for other applications like reducing voltage flicker or minimizing interactions with other voltage regulating devices.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Assessing the Solar Photovoltaic (PV) Potential in Puerto Rican Brownfields and Reservoirs: Detailed Results and Methodology Annex [Slides]

This is the technical annex for "Assessing the Solar Photovoltaic (PV) Potential in Puerto Rican Brownfields and Reservoirs." This study by the National Renewable Energy Laboratory (NREL) evaluates the potential for solar photovoltaic (PV) development on brownfields and reservoirs in Puerto Rico. Redeveloping these sites offers significant benefits, such as expanding energy infrastructure, supporting environmental remediation, and enhancing community revitalization. The study identifies up to 3.3 gigawatts (GW) of solar PV capacity, including 213 megawatts (MW) on closed landfills, 1-2.5 GW on contaminated sites, 78 MW on decommissioned plants, 21-50 MW on transmission line rights-of-way, and 636 MW on waterbodies for floating PV. This research highlights the strategic importance of investments and regulatory support to achieve Puerto Rico's goal of 100% clean energy by 2050.

14 SOLAR ENERGY↗
DOE OSTI2025

Unified Universal Control and Coordination of Inverter-Based Resources, and Validation for a PV + Battery Hybrid Plant

As renewable energy deployment grows, hybrid power plants (HPPs) combining photovoltaic (PV) and battery systems must evolve to offer both energy and grid stability services. These systems typically include a mix of grid-following (GFL) and grid-forming (GFM) inverters, presenting unique coordination and control challenges. This Department of Energy–funded project developed and validated a Unified Universal Control and Coordination (UUCC) framework for such PV + battery hybrid plants, enabling seamless and stable operation, including ultrafast black start, autonomous synchronization, and robust frequency and voltage regulation, under different grid conditions. The project significantly advanced the understanding of inverter-based resource (IBR) control by developing and validating three complementary system-level approaches for hybrid GFL/GFM operation: 1. A combined Virtual Resistance (VR)-based GFL and Virtual Oscillator Control (VOC)-based GFM method, where each inverter type is governed by a specialized control strategy. Together, these achieve stable, fast-response coordination, eliminating inrush current and enabling smooth black start and grid synchronization across a wide range of grid strengths. 2. A Deadbeat-based UUCC strategy, which uses discrete-time, switching-cycle-level control for both GFL and GFM inverters. This approach replaces traditional PI/PLL control with a control parameter-free, high-bandwidth framework that supports stable LVRT and instantaneous synchronization under all conditions. 3. A benchmark comparison with Siemens’ commercial GFM microgrid controller, which provided a fast baseline platform. The commercial approach decoupled v & f control was implemented on a commercial microgrid controller.The baseline commercial benchmark helped highlight superior transient response and black start performance offered by the deadbeat and VOC approaches. These technical contributions offer substantial improvements over conventional inverter control schemes, which often rely on slow phase-locked loop (PLL)-based synchronization, require careful control parameters tuning, and prone to unstable in weak grids with GFL inverters and in stiff grid with GFM inverters therefore challenging for hybrid GFL+GFM under all grid conditions. The deadbeat-based UUCC framework enables simpler, faster, and more robust operation of hybrid IBR systems using wide-bandgap (WBG) devices such as SiC power semiconductors. The rapid expansion of hybrid distributed energy resources (DERs), including residential and commercial PV-BESS installations such as Tesla Powerwall, PV with vehicle-to-grid (V2G) capability, and other integrated configurations, presents complex operational challenges for medium-voltage radial distribution feeders. These networks are subject to frequent disturbances such as faults, switching operations, rapid reclosing sequences, and feeder reconfigurations, all of which introduce dynamic stress on IBRs. In addition, planned feeder segmentation and deliberate islanding for resilience will require DERs that can autonomously perform blackstart, establish voltage and frequency references, and resynchronize with the main grid. The advanced deadbeat-based UUCC control and blackstart functionalities developed in this project directly address these requirements, enabling decentralized and autonomous operation of inverter-dominated DERs in distribution systems under a wide range of fault and reconfiguration scenarios. From a public benefit perspective, these innovations enable more reliable and cost-effective integration of renewable energy into distribution networks. The ability to autonomously black start and stabilize grids under varying grid conditions support accelerates recovery from outages and support decentralized resilient energy systems. By reducing system complexity and improving performance, this project lays critical groundwork for future inverter-dominated power grids that are clean, reliable, and accessible to all.

14 SOLAR ENERGY↗
DOE OSTI2026

Gaps in PV-Coupled Battery Modeling

With the rapid increase in battery attachment rates for PV systems and the continued qualification of storage for the ITC under OBBB, accurately characterizing PV-coupled batteries is becoming increasingly critical for the PV industry. This presentation will explore the key gaps in current best practices for modeling PV-coupled battery storage, including challenges such as battery thermal conditioning, the influence of dispatch strategies on battery value, the limitations of oversimplified degradation and performance models, and the absence of a centralized database containing sufficient battery parameters for accurate modeling. For behind-the-meter applications, we will also address issues like mismatched solar resource and load profiles, as well as uncertainties in future utility rates. Where applicable, we will quantify the impacts of these gaps on the accuracy and uncertainty of modeling efforts and highlight ongoing research aimed at addressing these challenges.

14 SOLAR ENERGY↗
DOE OSTI2015

Quantifying Reliability - The Next Step for a Rapidly Maturing PV Industry and China's Role

PV customers wish to know how long their PV modules will last, but quantitatively predicting service life is difficult because of the large number of ways that a module can fail, the variability of the use environment, the cost of the testing, and the short product development time, especially when compared with the long desired lifetime. China should play a key role in developing international standards because China manufactures most of the world's PV modules. The presentation will describe the steps that need to be taken to create a service life prediction within the context of a defined bill of materials, process window and use environment. Worldwide standards for cost-effective approaches to service-life predictions will be beneficial to both PV customers and manufacturers since the consequences of premature module failure can be disastrous for both.

14 SOLAR ENERGY↗
DOE OSTI2017

How to Estimate Demand Charge Savings from PV on Commercial Buildings

Rooftop photovoltaic (PV) systems are compensated through retail electricity tariffs - and for commercial and industrial customers, these are typically comprised of three components: a fixed monthly charge, energy charges, and demand charges. Of these, PV's ability to reduce demand charges has traditionally been the most difficult to estimate. In this fact sheet we explain the basics of demand charges, and provide a new method that a potential customer or PV developer can use to estimate a range of potential demand charge savings for a proposed PV system. These savings can then be added to other project cash flows, in assessing the project's financial performance.

14 SOLAR ENERGY↗
DOE OSTI2017

Terms, Trends, and Insights: PV Project Finance in the United States, 2017

This brief is a compilation of data points and market insights that reflect the state of the project finance market for solar photovoltaic (PV) assets in the United States as of the third quarter of 2017. This information can generally be used as a simplified benchmark of the costs associated with securing financing for solar PV as well as the cost of the financing itself (i.e., the cost of capital). This work represents the second DOE sponsored effort to benchmark financing costs across the residential, commercial, and utility-scale PV markets, as part of its larger effort to benchmark the components of PV system costs.

14 SOLAR ENERGY↗
DOE OSTI2017

Robust PV Degradation Methodology and Application

The degradation rate plays an important role in predicting and assessing the long-term energy generation of PV systems. Many methods have been proposed for extracting the degradation rate from operational data of PV systems, but most of the published approaches are susceptible to bias due to inverter clipping, module soiling, temporary outages, seasonality, and sensor degradation. In this manuscript, we propose a methodology for determining PV degradation leveraging available modeled clear-sky irradiance data rather than site sensor data, and a robust year-over-year (YOY) rate calculation. We show the method to provide reliable degradation rate estimates even in the case of sensor drift, data shifts, and soiling. Compared with alternate methods, we demonstrate that the proposed method delivers the lowest uncertainty in degradation rate estimates for a fleet of 486 PV systems.

14 SOLAR ENERGY↗
DOE OSTI2018

The Evolving Market Structure of the U.S. Residential Solar PV Installation Industry, 2000-2016

Market structure refers to the number of firms and the distribution of market shares among firms within an industry. In The Evolving Market Structure of the U.S. Residential Solar PV Installation Industry, 2000-2016, we examine market structure in the context of residential solar PV. We find that over 8,000 companies have installed at least one residential PV system, with about 2,900 companies active in 2016. The majority of residential PV installers are relatively small companies, with about half of installers installing fewer than five systems. At the same time, a subset of high-volume installers accumulated market share, especially beginning around 2010 with the emergence of alternative customer financing options.

14 SOLAR ENERGY↗
DOE OSTI2018

Costs of Upgrading Electric Distribution Grids to Integrate Increasing Solar PV Penetrations

The nation surpassed 1 million distributed PV systems in 2016 - installed primarily on the rooftops of residential and commercial buildings - and rapid growth has continued. At the end of 2017, 16.2 giga watts (GW) of distributed PV was installed in the United States. Although distributed PV still provides a small fraction of the total U.S. electricity supply, its contribution to some utility systems has become large very quickly - highlighting the increasing need to develop strategies that maximize PV's benefits to distribution grids while minimizing grid-integration costs.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2019

Hybrid Systems to Enable High Penetration PV

A model for PV plus energy storage and fuel cells was developed in the System Advisor Model (SAM). This model was used to evaluate the ramp rate and interconnection capacity factor for a hypothetical utility-scale plant for several configuration options. For PV only, the plant experienced 3345 violations of a 10%/minute ramp up limitation and a interconnection capacity factor of 17.6%. Adding a battery reduced the violations to 154 per year and the magnitude of the average violation to 2%. Adding a fuel cell to the PV system increased the capacity factor to 78% without improving ramp violations. Using a combined PV plus storage plus fuel cell arrangement maintained the improved capacity factor while reducing ramp up violations to 23, illustrating the potential to operate a hybrid system both to enable grid integration requirements and increase utilization of the interconnection.

14 SOLAR ENERGY↗