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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Solar Resource and Infrastructure Assessment for the Town of Westhampton

This report is a solar resource and infrastructure assessment for the town of Westhampton, Massachusetts. The assessment was funded through the National Renewable Energy Laboratory, Solar Energy Innovation Network (NREL SEIN) Solar in Rural Communities Program, as part of a project to develop a Community-Informed Proactive Solar Siting and Financing Model. As a first step, the project lead organization, UMass Clean Energy Extension prepared an assessment of existing infrastructure, resources, and potential solar development opportunities in participating municipalities, including Westhampton. This assessment was designed to describe relevant bylaws and infrastructure within the town, identify the types of solar facilities that could be developed, and quantify the total space available for each type of facility. In this report, we reviewed existing electricity grid infrastructure, and the potential to interconnect additional solar facilities. At the present time, both distribution lines providing electricity to Westhampton are oversaturated with authorized and proposed solar projects, and cannot accommodate additional solar projects to interconnect to the grid. Future upgrades could potentially free up additional capacity for new, large projects. Meanwhile, most three-phase lines could likely accommodate additional small-to-medium scale projects (under 200 kW), and most single-phase lines could likely accommodate additional projects under 50 kW in size. This description represents the local grid infrastructure as it is - planning for future scenarios of development could include recommendations for areas of grid infrastructure improvement to allow siting of distributed generation in locations preferred by the community. Future scenarios may also include the addition energy storage and other "non-wires alternatives."

14 SOLAR ENERGY↗
DOE OSTI2024

Solar Finance and Ownership Options

Communities facing specific solar project development opportunities or proactively planning their solar development strategies will need to have a basic understanding of solar financing and ownership options. How solar is financed and owned has large implications on how the solar project impacts local economic benefits, risk, and capital needs. This fact sheet provides a brief introduction to these considerations for local officials and community constituents to familiarize them with how local benefits and risks contrast across the basic ownership structures available.

14 SOLAR ENERGY↗
DOE OSTI2022

Community Planning for Solar: Defining Realistic Solar Development Options

This guide is designed to aid in assessing community preferences for solar development and financing alternatives. To evaluate community preferences regarding solar, it is necessary to define the range of realistic options for solar development possible in a community, including potential future targets for solar capacity, the mixes of development possible based on the solar resources available, and potential community benefits and solar ownership structures. This guide can help community officials, volunteers, and regional planning agency staff in constructing a realistic suite of options for solar development, based on existing state and local laws, available solar resources and infrastructure, and economic and financial considerations.

14 SOLAR ENERGY↗
DOE OSTI2022

Community Planning for Solar: Conducting Focus Groups for Solar Planning

This guide is designed to assist community officials, volunteers, and regional planning agency staff in conducting preliminary community meetings to learn about attitudes towards solar energy in your community. The guide will provide the key steps, timelines, facilitators' guide, and tips for hosting successful focus groups. Focus groups are meetings with a small group that represent a diversity of perspectives in your community. These differ from an open meeting in that focus groups include very specific questions that are prepared in advance, and all participants are given time to respond and understand various perspectives about solar energy. The guide concludes with a suggested template for reporting the results of your focus group or community meeting to your community more broadly. Holding community focus groups is part of assessing community preferences, as part of the Community Planning for Solar toolkit (ag.umass.edu/solarplanning). This guide is designed to help municipalities in Massachusetts and other states proactively plan for solar development in their communities. For more information, visit the UMass Clean Energy Extension (CEE) website (ag.umass.edu/clean-energy).

14 SOLAR ENERGY↗
DOE OSTI2022

Community Planning for Solar: Conducting a Community Solar Survey

This guide is designed to assist community officials, volunteers, and regional planning agency staff in conducting a survey of residents to learn about attitudes and development preferences towards solar energy within the community. The guide will provide the key steps, timelines, distribution options, ethics, and considerations that should be made in developing a survey distribution strategy. The guide also contains an overview of various question types and response categories, with considerations for the type of data that are needed for the study. The guide concludes with recommendations for managing data and databases, data visualization, and reporting results. The appendix includes samples of materials used in a solar energy survey, from invitation letters to the survey. This document is intended to provide a practical guide for implementing a survey in communities that are proactively planning for solar development. The guide offers a practical “how-to” plan for conducting a survey. It may be advantageous to consult with an expert in survey development who will be familiar with any methods and techniques described in this guide, but this is not necessary. This guide offers basic considerations and examples of questions and analyses to help a community understand preferences of the community.

14 SOLAR ENERGY↗
DOE OSTI2022

Community Planning for Solar: Compiling a Community Solar Action Plan

This document provides an annotated outline for a Community Solar Action Plan. This document is designed to assist community officials, volunteers, and regional planning agency staff in preparing a draft Community Solar Action Plan for a municipality, community, or other jurisdiction. Preparing a Community Solar Action Plan is the fifth step in the Community Planning for Solar process (ag.umass.edu/solarplanning). The plan is intended to be the culmination of the planning process. The contents of the plan will include summaries of information gathered as part of foregoing steps in the process, including completion of a Solar Resource and Infrastructure Assessment, administering of a Community Solar Survey, interpretation of survey results, and review of Solar Financing and Ownership Options and tools. Once the Community Solar Action Plan has been drafted, it should be reviewed by municipal board and commission members and presented at an open community forum. Any important comments or revisions can be incorporated before the final Community Solar Action Plan is approved and implemented. The approved Community Solar Action Plan is a living document that guides community solar planning action over time. As conditions change, new information becomes available, or actions progress over the life of the plan, adjustments may be necessary to maintain the plan's relevance. The Monitoring, Evaluating, and Updating Your Community Solar Action Plan fact sheet (Step 6, Item a) describes some things to consider when updating the Community Solar Action Plan over time.

14 SOLAR ENERGY↗
DOE OSTI2022

Monitoring, Evaluating, and Updating Your Community Solar Action Plan

The Community Solar Action Plan is a living document that guides community solar planning action over time. As conditions change, new information becomes available, or actions progress over the life of the plan, adjustments may be necessary to maintain the plan's relevance. This fact sheet describes some things to consider when implementing, monitoring, evaluating, and updating the Community Solar Action Plan over time.

14 SOLAR ENERGY↗
DOE OSTI2020

Semi-transparent p-type barium copper sulfide as a back contact interface layer for cadmium telluride solar cells

Optically transparent p-type materials play a critical role in transparent electronics including photovoltaic (PV) devices. P-type sulfide materials offer an alternative to oxides for PV application due to improved hole transport properties. Here, we report the solution-based synthesis of earth-abundant p-type transparent conducting barium copper sulfide (α-BaCu 4 S 3 , BCS) thin films. These films were characterized using scanning electron microscopy, X-ray diffraction, UV–Vis–NIR spectrophotometry, Raman spectroscopy, and spectroscopic ellipsometry. BCS films of ~100 nm thickness transmit >70% of visible light. We report on tests of the hole transport properties of these BCS films for cadmium telluride (CdTe) photovoltaics, finding that the BCS deposition process forms a beneficial tellurium (Te) rich surface on CdTe by selectively removing Cd from the surface. Based on our study, the BCS interface layer plays dual functions for CdTe PV devices as a hole transport material and as an etchant, enhancing the resulting device performance. We observed a significant increase in open-circuit voltage of CdTe solar cells with the BCS buffer layer. Furthermore, we discuss semitransparent CdTe solar cells with BCS as a hole transport layer and indium tin oxide as a finishing electrode. Semitransparent CdTe solar cells shows 13.3% conversion efficiency for the front side illumination and 1.2% efficiency for back side illumination, indicating high recombination of charge carriers generated close to the rear CdTe/BCS/ITO contact.

36 MATERIALS SCIENCE↗
DOE OSTI2021

PV System Owner's Guide to Identifying, Assessing, and Addressing Weather Vulnerabilities, Risks, and Impacts

The report is designed to help federal facility managers, engineers, contractors, and consultants identify the most common PV system vulnerabilities that could lead from mild to catastrophic loss of PV systems during severe weather events. The guide helps users understand the type and severity of severe weather that can occur at any given location, and provides pre- and post-storm operations and maintenance (O&M) measures that can reduce the potential for damage to a PV system during a severe weather event and help speed the recovery of a PV system damaged during a storm. The guide emphasizes safety in responding to damage from severe weather events.

14 SOLAR ENERGY↗
DOE OSTI2023

Cadmium Telluride Solar Cells: From Fundamental Science to Commercial Applications

In order to meet aggressive decarbonization goals, photovoltacs (PV) need to expand substantially. The current technology that heavily dominates the market, silicon (Si), comprises 95% of the world's PV production, is energy intensive to make, and can take up a substantial portion of the remaining carbon budget if expanded. Conversely, cadmium telluride (CdTe) comprises much of the remaining 5% of the global PV market and has a significantly lower carbon footprint than Si, historically costs less to produce, and is critically important to U.S. competitiveness in the global market. Importantly, CdTe still has room to grow, particularly related to efficiency because voltage has historically been much lower than what we calculate it should be. My research is focused in part on understanding this voltage deficit from a fundamental perspective by studying bulk materials and interfaces. One of the most important regions of the device is buried within the stack, so I developed a technique to cleave and reveal buried interfaces. This cleave technique has enabled a much better scientific understanding and allows us to make lightweight, flexible PV while maintaining low costs, high efficiency, and high throughput associated with standard module processing.

CdTe↗
DOE OSTI2020

Model of Operation-and-Maintenance Costs for Photovoltaic Systems

This article presents a method for calculating costs associated with operation and maintenance (O&M) of photovoltaic (PV) systems. It compiles details regarding the cost and frequency of multiple O&M services to estimate annual O&M costs ($\$$/year) for each year of an analysis period, the net present value ($\$$) of life cycle costs accumulated over the analysis period, and the reserve account amount ($\$$). Here we show that this method is an improvement over the previous averaged or levelized per-unit ($\$$/kW/year) valuations for estimating PV O&M costs, because it allows a detailed selection of services to perform based on system size, market served (e.g., residential, commercial, or utility), type and configuration of system components (e.g., micro-, string or central inverter) and site and environmental conditions (e.g., snow, pollen, bird populations). This model also distinguishes costs that vary from year to year and increase at different rates over time because of heuristic failure distributions (e.g. Weibull or Lognormal distribution) based on actuarial data for many of the services. This cost model was created by the PV O&M Working Group of researchers and industry, sponsored by DOE Solar Energy Technologies Office, and has been published in an on-line version hosted by SunSpec Alliance at apsuite.sunspec.org. A spreadsheet version is included with this paper as supplementary material.

14 SOLAR ENERGY↗
DOE OSTI2024

Solar-battery integrated DC system

A DC bus is connected to a PV array, a battery or both, to power a grid connected inverter load on the bus. A system and method is described for controlling current flow on a DC bus regardless of the type of inverter. A converter receives a DC battery voltage. A switching module controls current flow through the converter. A current generator generates a reference current in response to a reference voltage. A comparator connected at the output of the current generator compares the reference current with a battery current and outputs a signal to a controller. The controller generates a reference value. A PWM generator modulates the switch module to control current flow and energy flow between the DC bus and the battery. The current from the DC bus to the inverter is controlled to allow proper grid-connected operation regardless of inverter type.

Atcitty, Stanley↗
DOE OSTI2026

Quantum computing approach for building surface sunlit in urban-scale energy modeling

Solar shadow calculations are needed in building energy modeling and performance simulation of PV systems installed on roofs or facades of buildings. We present a quantum computing approach for calculation of building surface sunlit fractions by recasting solar visibility as a binary optimization problem solved by quantum annealing. Each triangulated surface centroid is encoded as a binary qubit indicating sunlit or shaded status. Geometric visibility constraints are derived from the Möller-Trumbore intersection algorithm and converted into a constrained quadratic binary model compatible with contemporary quantum annealers. The coefficients were embedded to D-Wave quantum computer. To demonstrate feasibility, we conducted a case study in San Francisco for a target building with 52 triangles and roughly 2700 nearby triangles within 50 m evaluated at representative winter and summer solar positions. The results demonstrated that quantum annealing can reliably calculate and distinguish sunlit from shaded surfaces. Quantum samples achieved average accuracy exceeding 92.4 %, with the aggregate surface-level agreement approaching 99.9 %. The outputs of quantum computers agreed closely with classical algorithms, indicating practical feasibility and promising scalability. Finally, the hourly sunlit fractions of building surfaces can be obtained for urban energy modelling. This is the first study to apply quantum computing to the solar shadow and building surface sunlit calculation. It introduces a new paradigm that differs fundamentally from traditional approaches.

Deng, Zhipeng↗
DOE OSTI2022

AlInP-passivated III–V solar cells grown by dynamic hydride vapor-phase epitaxy

We report the development of AlInP-passivated solar cells grown by dynamic hydride vapor-phase epitaxy (D-HVPE) with AM1.5G efficiencies of 26.0% for single-junction (1J) GaAs cells and 28.0% for GaInP/GaAs (2J) tandems. We compare the device performance of solar cells passivated with AlInP versus control cells passivated with GaInP, which has already enabled near-unity carrier collection in GaAs solar cells. 1J devices passivated with either AlInP or GaInP have an identical open-circuit voltage (V OC ) of 1.06 V and long-wavelength current collection near 95%, indicating that both window materials provide a similar degree of passivation. Adding AlInP passivation to each solar cell structure improves the current collection by 1.3 and 1 mA/cm 2 for the 1J and 2J, respectively. The AlInP also results in a top cell V OC boost of ~40 mV relative to a tandem device passivated only by a thin, highly doped GaInP emitter. Secondary-ion mass spectrometry measurements indicate that although O and Si both incorporate in the AlInP window, they do not appear in the subsequently grown absorber layers and do not impact its ability to passivate the front surface. We expect that these achievements, along with continued optimization, will enable parity of hydride vapor-phase epitaxy (HVPE)-grown device efficiencies with state-of-the-art devices grown by other epitaxial methods in the near future.

14 SOLAR ENERGY↗
DOE OSTI2024

Component-based SHGC determination of BIPV glazing for product comparison

Building-integrated photovoltaic (BIPV) systems are intrinsically designed to generate electricity and to provide at least one building-related function. When BIPV modules act as glazing products in windows, skylights or curtain walls, their ability to control the transmission of solar energy into the building must be characterised by a Solar Heat Gain Coefficient (SHGC) or g value (also known as Total Solar Energy Transmittance – TSET – or “solar factor”). For the comparison of BIPV glazing products consisting of one PV laminate and possibly further, conventional glazing layers separated by gas-filled cavities, the procedures documented in international standards for architectural glazing (e.g. ISO 9050 and EN 410) form a suitable starting point. Easily implemented modifications to these procedures are proposed to take both optical inhomogeneity (if relevant) and extraction of electricity from BIPV glazing units into account. Geometrically complex glazing and shading devices, and light-scattering glazing layers, are outside the scope of the proposed methodology; SHGC determination for obliquely incident solar radiation is also excluded. For these cases, the experimental calorimetric approach documented in [ISO 19467:2017; ISO 19467-2:2021] is recommended. The paper also presents results and conclusions from an implementation exercise and sensitivity study carried out by participants of the IEA-PVPS Task 15 on BIPV. The cell coverage ratio in the PV laminate, the thermal resistance offered by the glazing configuration, the choice of boundary conditions and the effect of extracting electricity were all identified as parameters which significantly affect the SHGC value determined for a given type of BIPV glazing. A practicable approach to accommodate the great variety of dimensions typical for BIPV glazing is also proposed. These findings should pave the way for modifying the existing component-based standards for architectural glazing to take the specific features of BIPV glazing into account.

14 SOLAR ENERGY↗