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At least 415 records · Page 23

All sources NASA NTRS DOE OSTI

DOE OSTI2023

Identifying impacts of process, precursors, and defects in metal halide perovskite solar cells

With efficiencies of halide perovskite solar cells stagnating over the last few years at values above 25% and approaching thermodynamic limits, focus must shift to ensuring stability of these devices over the long term. The overarching goal of this project was to understand the root causes of instability in halide perovskite solar cells. Our approach was rooted in fundamental scientific pursuits, determining at the molecular level those processes responsible for degradation of the metal halide perovskite system, either in the precursor ink, or in the solid state. We then used this understanding to show that degradation leads to midgap states in halide perovskite semiconductors, explaining loss in performance; also, this in-depth understanding allowed us to develop specifically targeted solutions to prevent these degradation mechanisms. These include guidance about amines in perovskite inks, solvents to use (and not to use), and impacts of Cs incorporation to perovskite inks and solids. Finally, we achieved our end-of-project goal and demonstrated an effective lifetime of a halide perovskite solar cell of 5000 h, including measurement of devices over 3000 h, amongst the longest in the field. Overall, this project has considerably pushed forward the science of perovskite degradation and sets examples and groundwork for future studies to enable halide perovskite solar cells to be a successful solar energy conversion technology.

14 SOLAR ENERGY↗

DOE OSTI2022

National Renewable Energy Laboratory History: 1977-2016

Like the political and energy landscape at the time, the birth of the Solar Energy Research Institute (SERI) in 1977, which then became the National Renewable Energy Laboratory (NREL) in 1991, was at times tumultuous. Born from a need for better energy solutions, the newly formed U.S. Department of Energy realized that creating an organization solely dedicated to clean energy was crucial to our nation's ability to achieve energy independence. Forty-five years later, the "little lab in the hills" is at the forefront of clean energy innovation and is helping tackle our most daunting energy challenges. This book documents the creation of SERI and the politics and context of the times, from 1977 to 2016. It's the culmination of extensive independent research and formal oral history interviews - and it took more than a decade to complete. The "NREL History Project" was launched in 2009 to comprehensively record the birth and history of the laboratory to date. The project concluded in 2016 but was put on hold until 2021.

Adams↗

DOE OSTI2024

Minimizing grid energy consumption in wastewater treatment plants: Towards green energy solutions, water sustainability, and cleaner environment

Wastewater treatment plants (WWTPs) consume significant amount of energy to sustain their operation. From this point, the current study aims to enhance the capacity of these facilities to meet their energy needs by integrating renewable energy sources. The study focused on the investigation of two primary solar energy systems in As Samra WWTP in Jordan. The first system combines parabolic trough collectors (PTCs) with thermal energy storage (TES). This system primarily serves to fulfill the thermal energy demands of the plant by reducing the demands from boiler units, which allows more biogas for electricity generation. The second system is a photovoltaic (PV) system with Lithium-Ion batteries, which directly produces electricity that will be used to cover part of the electrical energy demands of plant. To assess the optimal configuration, two distinct scenarios have been formulated and compared to the current case scenario (SC#1). The first scenario focuses on maximizing the net present value (NPV) and minimizing the levelized cost of electricity (LCOE). The second scenario is centred on minimizing the levelized cost of heat (LCOH). The findings indicate that both scenarios succeeded in reducing the reliance on the grid to a value that reach 1 %. Moreover, they both reduced biogas percentage in energy production from 88 % to approximately 65 % through the integration of the PV system. In terms of thermal demand, SC#2 reduced the reliance on biogas boiler units from 100 % to 25 %, while SC#3 achieved an even more impressive reduction to just 8 %. The best LCOE value was attained in SC#2, at 0.0895 USD/kWh, with an NPV of 10.54 million USD. Conversely, SC# 3 yielded an LCOH value of 0.0432 USD/kWh th compared to 0.0534 USD/kWh th USD for SC#2. In conclusion, despite their relatively high capital and operating costs, SC#2 and SC#3 managed to substantially decrease the annual electricity expenditure from approximately 2 million USD to 86,000 USD and 0 USD, respectively.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2020

Quantum Mechanical Evaluation of CZTS Properties for Photovoltaic Applications

As a quaternary semiconductor, CZTS (Cu 2 ZnSnS 4 ) shows promise as a thin-film solar cell material. The constituent elements in CZTS are abundant and non-toxic, and CZTS has an ideal band gap (~1.5 eV) for solar cell applications, which produces a large absorption coefficient. Unfortunately, the low efficiencies and difficulties in synthesizing the desired crystallographic phase (kesterite) and the associated formation of antisite defects limit its deployment. Using theoretical and computational tools, we investigated these current limitations, explored strategies to resolve these issues, and developed design guidelines to improve the efficiency of CZTS-based sunlight absorbers. We first sought to understand the challenges associated with synthesizing the kesterite phase and proposed ways to favor kesterite growth, thus adding to the understanding of CZTS photovoltaics. We also analyzed the major limitations at the atomic scale lowering the efficiency of CZTS: the low open-circuit voltage (V oc ) and the short carrier lifetime, thus addressing the technical effectiveness of CZTS photovoltaics. We believe the latter is due to Shockley-Read-Hall (SRH) recombination centers associated with point defects. We also studied the electronic structure of interfaces and defects introducing such recombination centers, and explored doping strategies to reduce SRH recombination. Ultimately, these efforts will benefit the public by contributing to the development of cheap and efficient solar energy conversion technologies made from abundant, non-toxic materials.

14 SOLAR ENERGY↗

DOE OSTI2021

The Solar Futures Study

The Solar Futures Study explores potential pathways for solar energy to drive deep decarbonization of the U.S. electric grid by 2035, and envisions how further electrification could decarbonize the broader U.S. energy system by 2050.

2050↗

DOE OSTI2022

Into the net zero emissions and climate change control: From solid carbon waste to effective solar convertors

Here, in this work, we demonstrate the potential for solar-to-heat conversion of carbon byproducts and their outstanding effects to reduce anthropogenic emissions. Those carbon byproducts are soots (biomass, evaporated carbon, etc.) as well as morphed graphenes. Our results cover optical characterization to demonstrate their suitability as heat capacitors and solar-to-heat convertors. Our raw materials are sustainable and currently considered environmental pollutants that require true attention to minimize global warming effects. Fortunately, they are ideal candidates to reduce the carbon footprints and can contribute towards a true net-zero environmental transition. We explore and demonstrate that soots are among the most competitive materials to transform solar energy into heat due to their absorption capacity, and durability. These materials are more competitive than commercial products and other known solar convertors demonstrating the superior thermosolar benefits. The best candidate is biomass with solar absorptivity, light emission, and cost reduction of 96, 85% and 15-fold, respectively, when compare to commercial products. Biomass and soot have comparable or better solar conversion characteristics, and sustainability than pristine carbon nanostructures and they are up to 3 orders of magnitude cheaper.

14 SOLAR ENERGY↗

DOE OSTI2025

AgriSolar Clearinghouse

The AgriSolar Clearinghouse (ASC) is a relationship-building, information-sharing network that promotes the co-location of solar energy systems and agriculture. The ASC website became accessible to the public after stakeholder approval, on October 27th, 2021. Phase 2 of the website was completed June 15, 2022, and includes an AgriSolar Atlas and a map of Financial Incentives.

14 SOLAR ENERGY↗

DOE OSTI2025

Direct solar self-catalyzing pyrolysis of natural gas to hydrogen and high-quality graphite (Final Technical Report)

This project, led by researchers at UCLA in partnership with Southwest Solar Technology (SST) and SolGrapH, successfully demonstrated a new method for producing clean hydrogen fuel and high-quality graphite using concentrated solar energy. The primary goal was to develop a technology that converts natural gas (primarily methane) into two valuable products—hydrogen gas and solid carbon—without releasing carbon dioxide (CO2) into the atmosphere. This process, known as solar thermal pyrolysis, uses heat from the sun to split the methane molecules directly.

03 NATURAL GAS↗

DOE OSTI2026

Powering Progress: Increasing capacity for State Agency participation in the development of solar guidelines

This project supported State Fish and Wildlife Agencies (SFWAs) in their participation in an industry-led process to develop nationwide utility scale solar energy wildlife guidelines intended to mitigate the impacts of large-scale solar development on wildlife and natural habitats. Led by the Association of Fish and Wildlife Agencies (AFWA), the project focused on documenting and communicating SFWA priorities, providing logistical and technical support for state engagement, and disseminating early outcomes to promote adoption and use.

14 SOLAR ENERGY↗

DOE OSTI2022

The Impact of Stochastic Perturbations in Physics Variables for Predicting Surface Solar Irradiance

We present a probabilistic framework tailored for solar energy applications referred to as the Weather Research and Forecasting-Solar ensemble prediction system (WRF-Solar EPS). WRF-Solar EPS has been developed by introducing stochastic perturbations into the most relevant physical variables for solar irradiance predictions. In this study, we comprehensively discuss the impact of the stochastic perturbations of WRF-Solar EPS on solar irradiance forecasting compared to a deterministic WRF-Solar prediction (WRF-Solar DET), a stochastic ensemble using the stochastic kinetic energy backscatter scheme (SKEBS), and a WRF-Solar multi-physics ensemble (WRF-Solar PHYS). The performances of the four forecasts are evaluated using irradiance retrievals from the National Solar Radiation Database (NSRDB) over the contiguous United States. We focus on the predictability of the day-ahead solar irradiance forecasts during the year of 2018. The results show that the ensemble forecasts improve the quality of the forecasts, compared to the deterministic prediction system, by accounting for the uncertainty derived by the ensemble members. However, the three ensemble systems are under-dispersive, producing unreliable and overconfident forecasts due to a lack of calibration. In particular, WRF-Solar EPS produces less optically thick clouds than the other forecasts, which explains the larger positive bias in WRF-Solar EPS (31.7 W/m 2 ) than in the other models (22.7–23.6 W/m 2 ). This study confirms that the WRF-Solar EPS reduced the forecast error by 7.5% in terms of the mean absolute error (MAE) compared to WRF-Solar DET, and provides in-depth comparisons of forecast abilities with the conventional scientific probabilistic approaches (i.e., SKEBS and a multi-physics ensemble). Guidelines for improving the performance of WRF-Solar EPS in the future are provided.

14 SOLAR ENERGY↗

DOE OSTI2022

Assessing Community Preferences Regarding Solar Development

Preparing a plan regarding solar development in your community requires bringing together people from a variety of backgrounds and perspectives, who often have strong feelings and preferences about the amount and location of local solar PV projects developed in their community. The planning process should be designed in an inclusive way, where meaningful community engagement is prioritized. With a topic such as solar development, which can elicit strong reactions among community members, proactive community engagement that is perceived as fair will likely lead to more favorable outcomes. Whether your community hosts large tracts of forest, brownfields, residential neighborhoods, and/or large buildings and parking lots, there are a variety of ways community members might envision growth of solar energy. The engagement process can help clarify how and where solar is preferred, so that local government can respond to future solar development requests or to initiate solar projects that are preferred by the community.

14 SOLAR ENERGY↗

DOE OSTI2021

An efficient method to identify uncertainties of WRF-Solar variables in forecasting solar irradiance using a tangent linear sensitivity analysis

Uncertainty in predicting solar energy resources introduces major challenges in power system management and necessitates the development of reliable probabilistic solar forecasts. As the first part of the development of probabilistic forecasts based on the Weather Research and Forecasting model with solar extensions (WRF-Solar), this study presents a tangent linear approach to identify input variables responsible for the largest uncertainties in predicting surface solar irradiance and clouds. A tangent linear analysis is capable of efficiently investigating sensitivities of output variables with respect to various input variables of WRF-Solar because this approach avoids the computational burden of perturbing the initial conditions of individual input variables. We develop tangent linear models (TLMs) for six WRF-Solar physics packages that control the formation and dissipation of clouds and solar radiation, and we evaluate the validity of TLMs using a linearity test. The tangent linear sensitivity analysis is conducted under various scenarios based on satellite observations and model simulations to consider realistic input conditions. A simple method is used to quantify the impact of the uncertainty of input variables on the output variables from the TLMs. The results demonstrate that uncertainties in the output variables that are the focus of this study—including global horizontal irradiance, direct normal irradiance, cloud mixing ratio, cloud tendency, cloud fraction, and sensible and latent heat fluxes—are highly sensitive to uncertainties in 14 input variables. This study indicates that the tangent linear method can identify key variables of physics modules in WRF-Solar that can be stochastically perturbed to generate ensemble-based probabilistic forecasts.

14 SOLAR ENERGY↗

DOE OSTI2022

NREL Pyrheliometer Comparisons: September 25 - October 1, 2022 (NPC-2022)

Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, for improving our understanding of Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements.

14 SOLAR ENERGY↗

DOE OSTI2022

NREL Pyrheliometer Comparisons: November 4 & 29, 2021 (NPC-2021)

Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, for improving our understanding of Earth’s energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements.

14 SOLAR ENERGY↗

DOE OSTI2024

NREL Pyrheliometer Comparisons: September 21-27, 2024 (NPC-2024)

14 SOLAR ENERGY↗

DOE OSTI2024

Trends, Insights, and Considerations for Agrivoltaics in the Northeast: Applying National Lessons Learned to the Case of Pennsylvania

There are unique challenges and opportunities at the nexus of agriculture and energy. This presentation will feature a social science overview of agrivoltaics, which is the practice of combining solar energy and agricultural production on the same land. Centering on recent research and commercial insights, this presentation will discuss the implications of lessons learned in the Northeast and highlight key considerations for future agrivoltaic R&D in Pennsylvania.

agriculture↗

DOE OSTI2020

Photosynthetic Antenna Research Center (PARC) (Final Report)

The Photosynthetic Antenna Research Center (PARC) was funded for five years (2009-2014) with the initial group of Energy Frontier Research Centers (EFRCs) by the U.S. Department of Energy. The PARC grant was then renewed for four more years (2014-2018). PARC was focused on basic scientific research aimed at elucidating the fundamental principles that underlie light harvesting and energy funneling in natural photosynthetic antennas and translating those principles into construction of biohybrid and bioinspired architectures to form the basis for next-generation systems for solar-energy conversion. PARC carried out high quality fundamental science on the path towards ambitious, visionary goals. The resources, infrastructure, and melding of scientific subdisciplines, techniques, and experiences made possible in PARC resulted in high risk but high reward and high impact research, enabling conceptual breakthroughs in light harvesting. PARC’s broad global vision was addressed through specific research and educational activities, and the legacy of intellectual and technical capacity that it built.

14 SOLAR ENERGY↗

DOE OSTI2022

Concentrated solar photovoltaic and photothermal system

The present invention provides a hybrid, concentrating photovoltaic-solar thermal (CPV/T) system and components thereof, and methods for converting solar energy to electricity at high efficiencies while capturing and storing solar thermal energy for later deployment.

Codd, Daniel↗