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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 OSTI2024

Status and Trends in the U.S. Voluntary Green Power Market: 2022 Data

Voluntary green power, for the purposes of this report, refers to renewable energy procurement by retail electricity customers above what is otherwise provided by load-serving entities. This report is part of an annual series of reports synthesizing trends in the United States voluntary green power market. In 2022, about 9.6 million retail electricity customers procured about 272 million megawatt-hours (MWh) of voluntary green power, representing about 38% of non-hydro renewable energy sales and about 6% of all U.S. retail electricity sales. Most of the remainder of U.S. renewable energy sales reflects renewable energy procured by load-serving entities to comply with state renewable energy mandates, also known as compliance-based procurement.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2023

Status and Trends in the U.S. Voluntary Green Power Market (2021 Data)

Voluntary green power, for the purposes of this report, refers to renewable energy procurement by retail electricity customers above state renewable energy mandates. In this report, we present data and key trends for voluntary green power markets, except for a small portion of voluntary purchasing where no data are available. In 2021, about 8 million retail electricity customers procured about 244 million megawatt-hours (MWh) of voluntary green power (Figure ES-1), representing about 27% of all U.S. renewable energy sales, about 39% of non-hydro renewable energy sales, and about 6% of all U.S. retail electricity sales. Most of the remainder of U.S. renewable energy sales reflects renewable energy procured by load-serving entities to comply with state renewable energy mandates, also known as compliance-based procurement.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

NREL Green Power Data 2020

This data book provides certain data behind figures and tables found in the NREL presentation "Status and Trends in the Voluntary Market (2020 Data)." These data reflect estimates based on the best available data.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

A techno-economic evaluation of solar-powered green hydrogen production for sustainable energy consumption in Belgium

Here this study focuses on the production and consumption of solar-powered green hydrogen in Belgium by comparing the costs of domestic production with those of imports from Morocco and Namibia. The levelized cost of hydrogen (LCOH) is determined via a techno-economic assessment considering various parameters including, power connectivity, electrolyzer types, location factors, and risk premium. The results show that the lowest LCOH can be achieved by on-grid Proton exchange membrane electrolyzers (PEMEL). LCOH of production in Belgium, Morocco, and Namibia with a PEMEL on-grid system are 5.64, 6.32 and 5.13 euro/kg H 2 , respectively. Thus, importing hydrogen from Namibia to Belgium is more competitive than domestic production. The sensitivity analysis suggests that a target LCOH of 3 euro/kg H 2 is achievable by importing from Namibia through various cost combinations. One of these combinations involves reducing the cost of PV panels to 222.3 euro/kW (70% reduction) and electrolyzers to 363.3 euro/kW (25% reduction).

08 HYDROGEN↗
DOE OSTI2022

Status and Trends in the U.S. Voluntary Green Power Market (2021 Data)

This data book provides certain data behind figures and tables found in the NREL presentation "Status and Trends in the Voluntary Market (2021 Data)." These data reflect estimates based on the best available data. Excluded Data This data book excludes data for certain figures using confidential survey data or purchased data for which NREL does not own the rights. In particular, renewable energy certificate (REC) price data are not included in this data book Rounding: Some estimates may be slightly inconsistent across tabs due to estimate rounding Citation for the data: E. O'Shaughnessy and J. Heeter. 2022. Status and Trends in the Voluntary Market. Golden, CO: NREL. For more information: contact Jenny Heeter (jenny.heeter@nrel.gov). For more information on voluntary green power markets see NREL's resources at https://www.nrel.gov/analysis/green-power.html. Acronyms CCA Community choice aggregation MWh Megawatt hour PPA Power purchase agreement RECs Renewable energy certificate

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

High entropy powering green energy: hydrogen, batteries, electronics, and catalysis

A reformation in energy is underway to replace fossil fuels with renewable sources, driven by the development of new, robust, and multi-functional materials. High-entropy materials (HEMs) have emerged as promising candidates for various green energy applications, having unusual chemistries that give rise to remarkable functionalities. This review examines recent innovations in HEMs, focusing on hydrogen generation/storage, fuel cells, batteries, semiconductors/electronics, and catalysis—where HEMs have demonstrated the ability to outperform state-of-the-art materials. We present new master plots that illustrate the superior performance of HEMs compared to conventional systems for hydrogen generation/storage and heat-to-electricity conversion. We highlight the role of computational methods, such as density functional theory and machine learning, in accelerating the discovery and optimization of HEMs. The review also presents current challenges and proposes future directions for the field. We emphasize the need for continued integration of modeling, data, and experiments to investigate and leverage the underlying mechanisms of the HEMs that are powering progress in sustainable energy.

batteries↗
DOE OSTI2024

Alternative electron pathways of photosynthesis power green algal CO2 capture

Abstract Microalgae contribute to about half of global net photosynthesis, which converts sunlight into the chemical energy (ATP and NADPH) used to transform CO2 into biomass. Alternative electron pathways of photosynthesis have been proposed to generate additional ATP that is required to sustain CO2 fixation. However, the relative importance of each alternative pathway remains elusive. Here, we dissect and quantify the contribution of cyclic, pseudo-cyclic, and chloroplast-to-mitochondrion electron flows for their ability to sustain net photosynthesis in the microalga Chlamydomonas reinhardtii. We show that (i) each alternative pathway can provide sufficient additional energy to sustain high CO2 fixation rates, (ii) the alternative pathways exhibit cross-compensation, and (iii) the activity of at least one of the three alternative pathways is necessary to sustain photosynthesis. We further show that all pathways have very different efficiencies at energizing CO2 fixation, with the chloroplast–mitochondrion interaction being the most efficient. Overall, our data lay bioenergetic foundations for biotechnological strategies to improve CO2 capture and fixation.

Biochemistry & Molecular Biology↗
DOE OSTI2022

High power picosecond green and deep ultraviolet generations with an all-fiberized MOPA

We demonstrate high power picosecond green and deep ultraviolet (DUV) lasers based on an all-fiberized master oscillator power amplifier (MOPA). The main power amplifier is fabricated with a highly Yb-doped large mode area (LMA) silicate glass fiber. It delivers 75.2-W laser output at 1029 nm with a pulse repetition rate of 10 MHz and a pulse duration of 70 ps. With a lithium triborate (LBO) crystal, a 43.0-W green output at 514.5 nm has been achieved with a pulse duration of 55 ps. With a caesium lithium borate (CLBO) crystal, a 14.5-W picosecond DUV output at 257 nm has been generated, which is the highest power for the all-fiber based DUV laser, to the best of our knowledge.

Pan, Lei (ORCID:0000000288896117)↗
DOE OSTI2025

Status and Trends in the U.S. Voluntary Power Market: 2023 Data

Voluntary green power, for this report, refers to renewable energy procurement by retail electricity customers above what is otherwise provided by load-serving entities. This report is part of an annual series of reports synthesizing trends in the U.S. voluntary green power market. In 2023, about 9.7 million retail electricity customers procured about 319 million megawatt-hours (MWh) of voluntary green power (Figure ES-1), representing a 17% increase over sales in 2022. Estimated voluntary green power market sales represented about 44% of non-hydropower renewable energy sales and about 8% of all U.S. retail electricity sales in 2023. Most of the remainder of U.S. renewable energy sales reflects renewable energy procured by load-serving entities to comply with state renewable energy mandates, also known as compliance-based procurement. The U.S. voluntary green power market is undergoing a clear shift toward long-term contracts, driven primarily by increasingly ambitious corporate renewable energy procurement targets.

2023↗
DOE OSTI2022

Status and Trends in the Voluntary Market (2021 Data)

Green power refers to renewable electricity voluntarily purchased by retail electricity customers. Renewable energy sources for green power include solar, wind, biomass, geothermal, and small-scale hydropower. This report summarizes data on the various ways in which voluntary purchasers including residential, commercial, and institutional customers purchase green power. We summarize key historic trends in U.S. voluntary green power markets and the current status of green power sales through seven products: utility green pricing programs, utility renewable contracts, competitive suppliers, unbundled renewable energy certificates, community choice aggregations, and power purchase agreements. It includes discussion of how the voluntary market may impact the grid.

ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Status and Trends in the Voluntary Market (2020 Data)

Green power refers to renewable electricity voluntarily purchased by retail electricity customers. Renewable energy sources for green power include solar, wind, biomass, geothermal, and small-scale hydropower. This report summarizes data on the various ways in which voluntary purchasers - including residential, commercial, and institutional customers - purchase green power. We summarize key historic trends in U.S. voluntary green power markets and the current status of green power sales through seven products: utility green pricing programs, utility renewable contracts, competitive suppliers, unbundled renewable energy certificates, community choice aggregations, and power purchase agreements. It includes discussion of how the voluntary market may impact the grid.

community choice aggregation↗
DOE OSTI2021

Deployment of Community Scale Solar Photovoltaic Energy Systems in Forest County Potawatomi Community

FCPC is a federally recognized tribe with a membership of more than 1400. The Tribe has a reservation in Forest County, Wisconsin, and tribal trust lands in Milwaukee County, Wisconsin, with significant governmental and business operations in both areas. Until relatively recently, FCPC was one of the poorest tribes in the Midwest. Due to its successful gaming operations, it now has improved its financial situation and is using its resources to benefit both its members and the general public through environmental and other community efforts, many of which are long-delayed because of the extended period of abject poverty. The Tribe has developed the long-term goal of becoming energy independent using renewable resources. In order to meet this goal, the Tribe has taken several important steps. As an interim step, FCPC is purchasing nearly 55 million kilowatt hours of renewable energy certificates (“RECs”) annually from certified renewable energy facilities in the United States. These RECs offset more than 100% of the present electricity use at all of the Tribe’s facilities. The Tribe is currently ranked number 11 on the Environmental Protection Agency’s (EPA) Top 20 Local Government list of green power purchasers and is a member of the EPA’s Green Power Partnership. The original project suggested small scale installations on tribal homes and certain government buildings. The Tribe suggested that the project would result in 730 kw installed. By revising the project, the Tribe was able to install 938 kw and owns the largest installation in Northern Wisconsin with the 800 kW installation at the Potawatomi Carter Casino Hotel (“PCCH”). The PCCH installation, in summer months, can provide near 90% of the use during daylight hours. Although tracking was not immediately available FCPC has since confirmed significant production with certain quarterly savings nearing $210,000. These installations provide a reduction in facility costs providing more revenue for Tribal services including cultural, health, sustainable food sources, environmental preservation and other Tribal initiatives. Further, the installations have resulted in positive steps towards the Tribe’s goals of energy sovereignty and the use of 100% renewable clean energy. Finally, the PCCH project, specifically, has had the additional benefit of providing a likely area for a microgrid. The size of the installation and offset achieved have pushed the Tribe toward planning for storage and a microgrid system that would both further the Tribe’s energy goals and provide a safe haven for the Community during times of need.

14 SOLAR ENERGY↗
DOE OSTI2024

South Asia Group for Energy - Bhutan

Bhutan's electricity system is already low-carbon through the use of hydropower. However, generation from hydroelectric plants is reduced during the dry winter months and will be impacted by climate change and other extreme weather events. Bhutan is mitigating these risks by diversifying their energy mix with clean energy resources. Bhutan is exploring photovoltaic (PV) solar energy development to enhance its energy system's overall resilience. To ensure efficient grid planning and solar integration, Bhutan's power generator, Druk Green Power Corporation, and the transmission and distribution utility, Bhutan Power Corporation, are partnering with the South Asia Group for Energy (SAGE) to develop their solar capabilities, integrate solar energy into the grid, and strengthen Bhutan's energy infrastructure and efficiency.

Bhutan↗
DOE OSTI2022

New bipolar host materials for high power efficiency green thermally activated delayed fluorescence $\mathrm{OLEDs}$

We report four bipolar molecules, namely m-CzPym, p-CzPym, m-CzTrz, and p-CzTrz, with carbazole (Cz) donor and a benzonitrile-substituted pyrimidine (Pym) or triazine (Trz) acceptor core were synthesized and characterized. The electron deficiency of heteroaryl cores together with the substitution pattern of benzonitrile were employed to tune the energy levels as well as the thermally activated delayed fluorescence (TADF) characteristics. The four molecules exhibited TADF behavior with inferior photoluminescent quantum yields (PLQYs) that limit their applications as emitters. These bipolar molecules were employed as TADF host materials for the benchmark TADF emitter 4CzIPN to achieve high-performing green TADF organic light-emitting diodes (OLEDs). Among the molecules, m-CzPym-hosted TADF-OLEDs achieved a maximum external quantum efficiency (EQE max ) of 31.5%, maximum power efficiency (PE max ) of 95.6 lm/W, and maximum current efficiency (CE max ) of 100.2 cd/A. Notably, p-CzPym-hosted TADF-OLEDs also achieved a PE max of 116.5 lm/W, turn-on voltage of 2.5 V, and impressive low efficiency roll-off performance (>89% of EQE max at 5000 cd/m 2 ), representing one of the highest efficiencies ever reported in 4CzIPN-doped devices. The high device efficiency can be ascribed to the balanced ambipolar carrier-transporting character of the host materials and high PLQY as well as the outstanding light outcoupling efficiency of the emitting layer.

42 ENGINEERING↗
DOE OSTI2023

Vegetation Management Lessons Learned and Helpful Tools

The InSPIRE Project is investigating questions around vegetation management and agrivoltaics at solar sites across the US. Results from research at three Enel Green Power pollinator-friendly solar sites in Minnesota have shown that the success of different pollinator-friendly seed mixes depend on the ecoregion and can vary from site to site. Results from the Enel Green Power sites also showed that weed coverage decreases dramatically by three years post seeding. The InSPIRE project has also created resources like The 5 C's of Agrivoltaics and an online agrivoltaics financial calculator to help farmers, land owners, developers, and facility operators with vegetation management at solar facilities. The PV-SMaRT calculator was created by the University of Minnesota in partnership with NREL to help with questions surrounding storm-water runoff at PV sites.

agrivoltaic↗
DOE OSTI2021

Mexico and U.S. Power Systems Under Variations in Natural Gas Prices

This study examines the impact of natural gas prices on the power systems of Mexico and the United States. For this, we develop an integrated modeling framework by soft linking three different techno-economic bottom-up models of the power and energy systems, one partial equilibrium model of the natural gas sector, and a partial equilibrium model of the Mexican energy sector. Our results show several interesting results: high natural gas prices raise the use of carbon-intensive technologies in the short-term and boost renewable investments at longer time intervals, increasing emissions in earlier periods and reducing them thereafter. Regarding system costs, because of more capital-intensive green power and lower expenditures in raw energy carriers, capital costs rise and operating costs decrease in the long haul. Furthermore, we see an increase in natural gas demand when its price is low, reducing long-term capital and operating costs through cheaper energy inputs in natural gas facilities and a lower share of capital-intensive renewable facilities in the power system. Concerning emissions, low natural-gas prices decrease coal use in the United States, reducing anthropogenic emissions until the last stages of the optimization period. For Mexico, they show heterogeneous results across models. Policymakers can use this study's results to understand the influence of natural gas prices in the Mexican and United States energy sectors.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2023

Large Format Composite Additive Manufacturing for Low-Head Hydropower

Hydropower with a small elevation change from inlet to outlet, known as “low-head” hydropower, is a relatively untapped resource for reliable green power generation. One major barrier to entry is the cost of the components needed to generate the power. Each installation site is unique, with various head levels, flow rates, and other unique site characteristics that drive up the cost of development and installation. As a result, custom-made components are necessary because the sites are intrinsically inefficient. However, customized parts are generally more expensive to manufacture than ready-made parts. Often times, the cost of custom-made components is so high that the low-head hydropower installation becomes non-viable. Additive manufacturing offers the ability to make custom components, ideal for one-off applications, at low costs that are well suited for the needs of low-head hydropower. Indirect additive manufacturing, such as making tools or dies rather than end use components, can also be used to make low-cost composite tooling as needed for these custom applications. This paper explores the use of additive manufacturing, both directly and indirectly, to produce the components of a turbine system for a low-head hydropower site. The parts were designed to form a unique modular system, which saves time for future designs and iterations. The system has operated for more than three years without failure at a test site in Wisconsin, USA. This work serves as a basis for future application of AM to low-head systems, in which the modular components can be customized for each unique hydropower installation.

36 MATERIALS SCIENCE↗