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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Technical, economic, and load-following capabilities assessment of grid-connected geothermal and geothermal-solar hybrid systems

The technical and economic performance as well as the load-following capabilities of grid-connected geothermal hybrid systems were assessed in this work. The analyzed geothermal hybrid configuration is composed of a binary geothermal plant integrated with a concentrating solar-thermal system and underground thermal energy storage (UTES) through a primary heat exchanger. Physics-based models for the hybrid system for plant generation capacities of 1, 25, and 50 MW were developed from validated models for each subsystem. Also, an economic model was developed that accounts for different hybrid system capabilities, solar field sizes, and thermal storage duration. The advantage of the geothermal hybrid system was assessed by comparing the performance with the baseline benchmark geothermal plant with a similar configuration and generation capacity. It was found that hybridizing geothermal plants with concentrating solar and thermal energy storage not only improves the thermal efficiency by up to 8 percentage points when additional heat from the solar-UTES loop rises the evaporator temperatures from 70 to 125 °C, but also enhances the load-following capability for the geothermal plant, which can meet a typical residential load profile with a power rate of change 0.25 kW/s with an absolute error under 13 kW for a 1 MW plant. Other benefits of hybridization include resource preservation and a potential LCOE reduction of up to 56% for a 50 MW geothermal hybrid plant having a 50% solar share, a 1.4 solar multiple, and 24-h storage capacity. The results presented in this work demonstrate that hybridizing geothermal systems transforms them into a flexible and cost-effective solution for addressing the dynamic requirements of modern electric grids.

15 GEOTHERMAL ENERGY↗
DOE OSTI2023

The Internal Compound Parabolic Concentrator (ICPC): a Novel Low Cost Solar Thermal Collection System for Desalination Processes

The research team at UC Merced designed, prototyped, and tested (1) a novel low cost non-tracking solar thermal collector/concentrator called the Integrated Compound Parabolic Concentrator (ICPC) and (2) a low-cost phase-change thermal energy storage system. Together these technologies can significantly reduce the levelized cost of heat from solar thermal sources while also incorporating features of dispatchability and portability. The ICPC allows elevated temperature and efficiency in a low cost, non-tracking collector. The collector has demonstrated 60% ±4% solar to thermal modules efficiency at fluid outlet temperature of 120°C. The raw material cost of the collector system is reduced by utilizing low cost aluminum minichannels. The collector design is also amenable to economic mass production. A 200 tube, 10 kW prototype array was constructed and tested, yielding over 6 kWh/day on average at outlet fluid temperature exceeding 120°C.

14 SOLAR ENERGY↗
DOE OSTI2024

Green-Field Geothermal/Solar Designs (Cooperative Research and Development Final Report)

Geothermal power (GEO) and concentrating solar power (CSP) can be integrated to obtain the best aspects of both systems. The green-field design will utilize the full potential of the higher-temperature CSP sector by having a topping solar steam turbine and a bottoming geothermal cycle. In the proposed hybrid cycle, geothermal energy can be converted into electricity at a higher cycle efficiency because of the high-temperature topping cycle during the daytime. CSP benefits from lower-cost solar collectors, a less expensive topping turbine, and virtual elimination of the heat rejection system cost. The green-field case study will be focused on a geothermal resource site which will deliver the 160 - 220 °C pressurized brine at the inlet of power block. While the case study will look at a single case study, the tools to be developed as part of the project will be available to model annual performance of GEO/CSP hybrids for new greenfield projects (may also be applied to certain types of brown-field retrofits). The evaluation tools will also calculate important economic parameters such as the levelized cost of energy (LCOE) and the internal rate of return (IRR).

14 SOLAR ENERGY↗
DOE OSTI2021

Perovskite Solar Cells Go Bifacial—Mutual Benefits for Efficiency and Durability

Bifacial solar cells hold the potential to achieve a higher power output per unit area than conventional monofacial devices without significantly increasing manufacturing costs. However, efficient bifacial designs are challenging to implement in inorganic thin-film solar cells because of their short carrier lifetimes and high rear surface recombination. The emergence of perovskite photovoltaic (PV) technology creates a golden opportunity to realize efficient bifacial thin-film solar cells, owing to their outstanding optoelectronic properties and unique features of device physics. More importantly, transparent conducting oxide electrodes can prevent electrode corrosion by halide ions, mitigating one major instability issue of the perovskite devices. Here, the theory of bifacial PV devices is summarized and the advantages of bifacial perovskite solar cells, such as high power output, enhanced device durability, and low economic and environmental costs, are reviewed. The limitations and challenges for bifacial perovskite solar cells are also discussed. Lastly, the awareness of bifacial solar cells as a feasible commercialization pathway of perovskite PV for mainstream solar power generation and building-integrated PV is advocated and future research directions are suggested.

14 SOLAR ENERGY↗
DOE OSTI2024

IBR Digital Supply Chain Gap Analysis and Recommendations

The adoption of clean energy technologies, including solar photovoltaics, continues to introduce non-traditional stakeholders to the operations and planning of the electric system. Stakeholders such as manufacturers, vendors, owners, aggregators, and others are enabling the adoption, integration, and optimum operations of solar technologies at accelerated rates. Inverters form the foundation of many digitally controlled energy sources for clean energy technologies, including Solar, Battery Energy Storage Systems, Hybrid Systems, and Hydrogen Fuel Cells. Their supply chain is complex, a series of microchips, electronic switches and other components making up its primary functions. The complexity of this space and the growing digitization associated with these components can create supply chain cyber risks. One measure to mitigate cybersecurity attacks is proper digital supply chain security. The U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO), in partnership with the Cybersecurity, Energy, Security, and Emergency Response (CESER) office, is hosting a workshop to bring together solar vendors and services providers to discuss digital supply chain security for solar systems and challenges and opportunities in the transitioning to a fully domestic supply chain for solar energy in the U.S. This workshop will support the Securing Solar for the Grid (S2G) and Energy Cyber Sense program activities. During the workshop, industry experts and researchers from DOE National Laboratories will discuss the current solar supply chain landscape and the transition to domestic manufacturing of solar components in the U.S. Tools and techniques to better manage and secure the digital supply chain of solar devices and systems will be discussed.

cybersecurity↗
DOE OSTI2020

On-device lead sequestration for perovskite solar cells

Perovskite solar cells, as an emerging high-efficiency and low-cost photovoltaic technology face challenges on their way towards commercialization. Substantial improvements have been made to device stability but potential issues with lead toxicity and leaching from devices remain relatively unexplored. The potential for lead leakage could be perceived as an environmental and public health risk when using perovskite solar cells in building-integrated photovoltaics. Here we present a chemical approach for on-device sequestration of more than 96 per cent of lead leakage caused by severe device damage. A coating of lead-absorbing material is applied to the front and back sides of the device stack. On the glass side of the front transparent conducting electrode, we use a transparent lead-absorbing molecular film containing phosphonic acid groups that bind strongly to lead. On the back (metal) electrode side, we place a polymer film blended with lead-chelating agents between the metal electrode and a standard photovoltaic packing film. The lead-absorbing films on both sides swell to absorb the lead, rather than dissolve, when subjected to water soaking, thus retaining structural integrity for easy collection of lead after damage.

14 SOLAR ENERGY↗
DOE OSTI2026

Roadmap for Solar Photovoltaic (PV) Cybersecurity: A vision for improving cyber maturity of distributed and utility-scale solar energy installations

As the solar energy sector continues to expand, its integration into the broader energy infrastructure presents both unprecedented opportunities and new risks. The increasing reliance on digital technologies and interconnected systems in solar energy creates an expanded attack surface for motivated cyber adversaries. Cyberattacks have the potential to cause disruptions in energy production, damage to equipment, financial losses, and compromises in national security. Therefore, ensuring robust cybersecurity measures is paramount to protect the integrity, availability, confidentiality, and access control of solar energy systems. However, there are still key gaps and challenges to be addressed in industry and research, which stakeholders must race to address as they combat a growing number of real-world cyber incidents that affect solar energy systems and a growing number of vulnerabilities discovered and disclosed in key types of equipment. This roadmap explore the current state of solar PV cybersecurity and the gaps and challenges still to be addressed.

14 - SOLAR ENERGY↗
DOE OSTI2020

Complementary relationship between small-hydropower and increasing penetration of solar photovoltaics: Evidence from CAISO

To achieve the 100% green electricity goal, we need to understand the relationship between resources in the market and identify the flexible clean resources (i.e., hydropower) to integrate power from wind and photovoltaic (PV). This paper reveals a complementary relationship between small hydropower plants and solar PVs in the California Independent System Operator (CAISO) based on the system-wide hourly generation data from 2013 to 2017. When the solar PV increases its portion in the generation mix by 1%, small hydro will increase its portion by 0.01–0.06%. Such response is obvious in the net demand peak hours, both morning and evening. The low operation cost, flexibility, and dispatchability of small hydro in CAISO explain this complementarity. Due to its benefit in emission and low Levelized Cost of Electricity (LCOE), it is suggested to consider more small hydro projects to accommodate additional PV capacity for the 100% green electricity goal. Our estimation indicates that the current feasible potential of small hydro is sufficient, if the relation stays the same over years. If developers can mitigate the environmental impact, more technical potential will become feasible. Thus, small hydro could integrate more solar PV and reduce the demand for natural gas plants and batteries.

13 HYDRO ENERGY↗
DOE OSTI2024

Yet Another Sunshine Mystery: Unexpected Asymmetry in GeV Emission from the Solar Disk

The Sun is one of the most luminous γ-ray sources in the sky and continues to challenge our understanding of its high-energy emission mechanisms. This study provides an in-depth investigation of the solar disk γ-ray emission, using data from the Fermi Large Area Telescope spanning 2008 August to 2022 January. We focus on γ-ray events with energies exceeding 5 GeV, originating from 0°5 angular aperture centered on the Sun, and implement stringent time cuts to minimize potential sample contaminants. We use a helioprojection method to resolve the γ-ray events relative to the solar rotation axes and combine statistical tests to investigate the distribution of events over the solar disk. We found that integrating observations over large time windows may overlook relevant asymmetrical features, which we reveal in this work through a refined time-dependent morphological analysis. We describe significant anisotropic trends and confirm compelling evidence of energy-dependent asymmetry in the solar disk γ-ray emission. Intriguingly, the asymmetric signature coincides with the Sun's polar field flip during the cycle 24 solar maximum, around 2014 June. Our findings suggest that the Sun's magnetic configuration plays a significant role in shaping the resulting γ-ray signature, highlighting a potential link between the observed anisotropies, solar cycle, and the solar magnetic fields. These insights pose substantial challenges to established emission models, prompting fresh perspectives on high-energy solar astrophysics.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Social Aspects and Considerations for Agrivoltaics Implementation

Integrated PV technologies - such as agrivoltaics - have potential to address challenges associated with siting and land use for solar. This presentation provides an overview of agrivoltaic R&D activities in the United States and focuses on the non-technical aspects of implementation, specifically social considerations around collaboration, planning, and acceptance.

14 SOLAR ENERGY↗
DOE OSTI2022

The National Solar Radiation Database (NSRDB) Fiscal Years 2019-2021(Final Report)

The National Solar Radiation Database (NSRDB) is the leading public source of high-resolution solar resource data in the United States, with more than 166,000 users annually. This database represents the state of the art in satellite-based estimation of solar resource information and uses a unique physics-based modeling approach that enables improvements in accuracy with the deployment of the next-generation geostationary satellites. Making the highest quality, state-of-the-art, regularly updated data sets available on a timely basis for users reduces costs of solar deployment by providing accurate information for siting studies and system output prediction, and thereby reduces levelized cost of energy. Also, high-resolution information from the NSRDB enables moving beyond levelized cost of energy when valuing the impact of renewables on the grid. Additionally, the NSRDB enables the integration of large amounts of solar on the grid by providing critical information about solar availability and variability that is used to enhance grid reliability and power quality.

14 SOLAR ENERGY↗
DOE OSTI2019

Developing Efficient Perovskite/Silicon Tandem Devices

This project aims at developing highly efficient perovskite/silicon tandem solar cells by developing efficient perovskite top cells, silicon bottom cells, and monolithically integrating the subcells for highly efficient tandem solar cells. The project focused on increasing the efficiency of perovskite solar cells to 20% and understanding related materials science and device physics, as well as developing a compatible bottom high-efficiency c-Si solar cell. The perovskite cells with a wide bandgap of 1.61 eV and 1.84 eV are fabricated by a low-cost, low-temperature, scalable solution process on lower bandgap silicon bottom cells. The bandgaps of perovskite top cells have been tuned between 1.61 eV and 1.84 eV by composition engineering mainly through controlling the halide mixing ratio in perovskite materials. The efficiencies of the wide bandgap perovskite solar cells have been improved to an excellent efficiency of 21.0% for perovskites with a bandgap of 1.63 eV with increased grain size, reduced energy disorder at cathode contact, and defect passivation. We invented a solvent annealing approach with solvent vapor during thermal annealing to enlarge grain size of perovskite film which reduces the charge trap density and improves the device efficiency. Moreover, we discovered that the non-wetting surface could further increase the grain size for perovskite films, because non-wetting surface could prevent the formation of too dense nuclei from heterogeneous nucleation process. We proposed to reduce the energy disorder of organic charge extraction layer to reduce the power loss in perovskite cells. We pioneered defect passivation concept and techniques to suppress the charge non-radiative recombination in perovskite solar cells to boost the efficiency. For the silicon bottom cell development, different from the conventional silicon cell work under full illumination, the light available for the silicon bottom cell in tandem structure is mainly NIR region. We developed a NIR enhanced silicon cell with efficiency of 21.2% by applying a double-layer antireflection coating at the front side and a MgF2 back reflector layer at the rear side. For the perovskite/silicon tandem device, we achieved a highest reported power conversion efficiency of 25.4% in 2018, and further increased the efficiency up to 26.0% in 2019. The research on tandem solar cells focused on reducing reflection loss to <5% at spectrum of 300-1100 nm by antireflection layer, tuning the bandgap of perovskite film for matched current density between sub-cells, and utilizing a ITO layer between perovskite top cell and silicon bottom cell as interconnect layer without Voc loss. Finally, we developed a blading technique to fabricate perovskite films which produces perovskite solar cells with comparable or even superior efficiency to those made by non-scalable spin coating method. This paves the way for scaling up perovskite/silicon tandem solar cells using solution approach.

14 SOLAR ENERGY↗
DOE OSTI2021

Pro2R: Procurement of Ramping Product and Regulation in CAISO Using Probabilistic Solar Power Forecasts

This presentation summarizes the objectives and findings from the project titled, "Pro2R: Coordinated Procurement of Ramping Product & Regulation in CAISO Using Probabilistic Solar Power Forecasts," funded by DOE SETO. The goal is to develop cutting edge probabilistic solar power forecasting methods, and integrate them into ISO market operations. The team has integrated in two ways: 1) to procure ramping product and regulation requirements (ancillary services) in the California ISO market, and 2) to develop an open source visitation and ramp alert related situational awareness using probabilistic forecasts. This deck also summarizes the results from the use of machine learning methods to relate probabilistic solar forecasts to the the needs for flexible ramp product in the California ISO system.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2020

New Technologies for Power System Operation and Analysis, 1st Edition

New Technologies for Power System Operation and Analysis considers the very latest developments in renewable energy integration and system operation, including electricity markets and wide-area monitoring systems and forecasting. Helping readers quickly grasp the essential information needed to address renewable energy integration challenges, this new book looks at basic power system mathematical models, advanced renewable integration and system optimizations from transmission and distribution system sides. Sections cover wind, solar, gas and petroleum, making this a useful reference for all engineers interested in power system operation.

electricity markets↗
DOE OSTI2023

Beneficial Integration of Energy Storage and Load Management with Photovoltaic (PV)

In recent years, a number of industry activities have aimed at addressing the integration challenges posed by the variability and uncertainty of higher penetration of renewable generation sources, like solar photovoltaic (PV) – one of the key objectives of the Sustainable and Holistic Integration of Energy Storage and Solar PV (SHINES) program launched by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE). This EPRI led Beneficial Integration of Energy Storge, and Load Management with PV project aimed to design, develop, and demonstrate end-to-end distributed energy resource (DER) integration solution to build on these activities. EPRI led project team designed and implemented a local controller that uses model predictive control (MPC) algorithm to optimally manage DERs on site by planning for a receding horizon while executing the control settings for the first step of its plan. The team has also developed a system controller to interface with the local controller to demonstrate the hierarchical control and how it can leverage DER capabilities to address challenges like over voltage and thermal limit violations which typically limits the DER hosting capacity of distribution feeders. Team has demonstrated how the local controller with optimization algorithm can effectively manage controllable loads like HVAC, water heater, and pool pumps to allow for greater integration of PV with relatively smaller energy storage system requirements. Optimal utilization of the load control can also reduce the depth of discharge of batteries to meet grid export/import limit from behind-the-meter (BTM) DERs. Proper utilization of DER capabilities via local control intelligence, like the one developed and demonstrated in this project can help the industry to address integration challenges of higher penetration of solar PV in economically efficient manner. This can help to accelerate deployment of clean renewable energy systems at lower societal cost.

14 SOLAR ENERGY↗
DOE OSTI2022

Mexico Clean Energy Report

This report provides an assessment of Mexico's clean energy resource potential and pathways for rapidly deploying renewable energy technologies to enable Mexico to reach its goal of 35% renewable energy by 2024 within the current legal and regulatory framework. An appendix to the report includes the results of the 2024 Renewable Energy Integration Study, and technology chapters on wind, solar, geothermal, hydropower, transport electrification, and green hydrogen, detailing current state, resource potential, and deployment opportunities and recommendations. Additional sections include transmission, a section on the challenges and solutions for the integration of variable generation resources, and a summary of benefits.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗