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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

A method for assessing economic, environmental, and reliability tradeoffs of interregional transmission connecting ERCOT (the Texas grid) to the eastern and western grids

Reliable development of the power grid is an evolving concern for humanity due to extreme weather that frequently threatens power sector infrastructure. The state of Texas is a uniquely structured testbed for grid planners to study when looking for solutions to development, innovation, and overcoming such challenges. Because of its size and islanded structure, Texas is small enough to model, but big enough to matter. Texas is a global leader in energy production, energy consumption, and maintains an unusually diverse fuel mix. In addition, the state has experienced winter freezes, heat waves, wind storms, droughts and floods that have threatened power sector infrastructure or caused recent blackouts and calls for demand side conservation. One of the most devastating of these events was the North American winter storm, dubbed “Winter Storm Uri” by the Weather Channel, that froze the region in February 2021 and led to an extended power outage event that put the majority of Texan residents in darkness for days. While preparing to avoid such outage events in the future, various tools have been proposed to improve grid reliability, including energy efficiency, demand response, and distributed energy resources. An additional option would be to develop interregional transmission that connects the Texas grid to other national grids. To assess the merits of this idea, we developed a novel, universally-applicable and internationally-relevant framework to study how the Texas grid would evolve alongside access to various interregional ties. This method allows us to stress the synthetic grid structure and analyze how it would respond to the shock of a simulated winter storm event. Our method leverages open-source modeling tools, such as PowerGenome, pyGRETA, and GenX to synthesize unique zonal grid data, construct a consolidated network of model regions, and simulate different developmental pathways of capacity expansion and operational dispatch. We demonstrate our method with an analysis connecting the Electric Reliability Council of Texas (ERCOT), the grid that serves most of Texas, the Western Electricity Coordinating Council (WECC), the grid that serves the western half of the contiguous U.S., and the Eastern Interconnect, the grid that serves the eastern half of the contiguous U.S. Our results indicate that the cost-optimal capacity of interregional transmission connecting the ERCOT grid to other grids lies between 9–13 GW assuming baseline conditions. Building this amount of connecting capacity in one or multiple directions lowers the costs and emissions of development and operation by up to $16 billion and 257 million metric tonnes (MMT) respectively. Additionally, our results show that the interregional connections between ERCOT and other national grids reduce the amount of total load shed required through mild winter storm events. However, our results also show that there is a threshold of very extreme winter storm conditions, spanning multiple service areas, above which the connections exacerbate resource adequacy problems. Therefore, the results indicate that the connections need to be carefully planned alongside the rest of the grid infrastructure to avoid over-reliance on specific resources or technology options.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Overcoming the sensitivity vs. throughput tradeoff in Coulter counters: A novel side counter design

We report microfabricated Coulter counters are attractive for point of care (POC) applications since they are label free and compact. However, these approaches inherently suffer from a trade off between sample throughput and sensitivity. The counter measures a change in impedance due to displaced fluid volume by passing cells, and thus the counter's signal increases with the fraction of the sensing volume displaced. Reducing the size of the sensing region requires reductions in volumetric throughput in the absence of increased hydraulic pressure and sensor bandwidth. The risk of mechanical clog formation, rendering the counter inoperable, increases markedly with reductions in the size of the constriction aperture. We present here a microfluidic coplanar Coulter counter device design that overcomes the problem of constriction clogging while capable of operating in microfluidic channels filled entirely with highly conductive sample. The device utilizes microfabricated planar electrodes projecting into one side of the microfluidic channel and is easily integrated with upstream electronic, hydrodynamic, or other focusing units to produce efficient counting which could allow for dramatically increased volumetric and sample throughput. The design lends itself to simple, cost effective POC applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Tradeoffs among indoor air quality, financial costs, and CO 2 emissions for HVAC operation strategies to mitigate indoor virus in U.S. office buildings

Adapting building operation during the COVID-19 pandemic to improve indoor air quality (IAQ) while ensuring sustainable solutions in terms of costs and CO 2 emissions is challenging and limited in literature. Our previous study investigated different HVAC operation strategies, including increased filtration using MERV 10, MERV 13, or HEPA filters, as well as supplying 100% outdoor air into buildings for a system initially sized for MERV 10 filtration. This paper significantly extends that research by systematically analyzing the potential financial and environmental impact for different locations in the U.S. The previous medium office building system model is improved to account for operation in different climates. New evaluation metrics are created to consider the comprehensive impact of improving IAQ on costs and CO 2 emissions, using dynamic emission factors for electricity generation depending on the location. HVAC operation strategies are studied in five different locations across the United States, with distinct climates and electricity sources. In four of the five locations, MERV 13 filtration offers the best improvement in IAQ per increase in costs and emissions relative to MERV 10. The exception is the mildest climate of San Diego, where use of 100% outdoor air provides the best IAQ with a limited increase in costs and emissions. Finally, a system not sized for HEPA filtration can lead to increased costs and emissions without much improvement in IAQ.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

How to support EV adoption: Tradeoffs between charging infrastructure investments and vehicle subsidies in California

Supporting the adoption of zero-emission vehicle (ZEVs), including plug-in electric vehicles (EVs), has become a priority for governments due to their ability to reduce petroleum demand, improve air quality, and reduce carbon dioxide (CO2) emissions. Optimal strategies to accelerate EV adoption must weigh the relative value of alternative policy mechanisms to consumers, including public charging infrastructure and vehicle purchase subsidies. We use a historically validated light-duty vehicle consumer choice tool, the ADOPT model, to simulate personal light-duty vehicle adoption and related emissions in California. ADOPT is updated to incorporate a quantification of the tangible value of public charging infrastructure, allowing us to simulate the impact of investments in public charging infrastructure and vehicle purchase subsidies under different scenarios. We show that both policies result in increased EV adoption, with the most effective policy varying depending on vehicle technology assumptions. Under conservative technology improvement assumptions, infrastructure investments are most effective in promoting EV sales and reducing CO2 emissions, while under optimistic technology improvement assumptions a combination of infrastructure and subsidies best supports EV sales and CO2 emission reductions.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

Power and energy capacity tradeoffs in an all-aqueous copper thermally regenerative ammonia battery

Thermally regenerative ammonia batteries (TRABs) can provide energy storage and produce electrical power from low-grade waste heat instead of electricity. The use of all-aqueous copper-based electrolytes has recently produced higher power densities than those achieved using previous TRAB approaches based on reversible metal deposition and dissolution processes, but further gains are possible in power and energy density. We investigated the limitations of power and energy density and how they are impacted by the electrolyte composition and discharge currents. By increasing the ammonia concentration from 1 to 5 M, the power density of the battery increased from 11.2 to 28.5 mW cm –2 , but the energy density decreased from 0.56 to 0.31 Wh L –1 . Increasing discharge current densities from 4 to 12.5 mA cm –2 increased the average power density during discharge from 2.4 to 5.9 mW cm –2 without appreciable losses in energy density. Increasing the copper concentration from 0.1 to 0.5 M increased both energy density to 2.15 Wh L –1 and energy efficiency to 2.2% but did not substantially impact the power density. Furthermore, these results represent the highest performance metrics achieved for a low-grade waste heat to electricity system.

25 ENERGY STORAGE↗
DOE OSTI2026

Large-Scale Carbon Removal Will Create Public Health, Economic, and Climate Tradeoffs

Economy-wide efforts to achieve net-zero emissions offer both climate and air quality-related public health benefits from reducing fossil fuel combustion. We explore the expected costs and benefits if carbon dioxide removal (CDR) is deployed at scale in support of these efforts. Six leading forms of CDR at two levels of deployment are compared to a scenario with no U.S. climate action. We find that heavy reliance on CDR avoids a $2.5-5.8 trillion USD2020 in climate damages, provides $2.8-6.5 trillion USD2020 public health benefits, returns $5-6 trillion USD2020 in CDR revenues, but requires $11-13 trillion USD2020 CO2 mitigation cost, cumulatively by 2050 in the U.S. In contrast, lower reliance on CDR requires much deeper near-term fossil-fuel reductions, which increases mitigation costs by 52% but also creates 26% higher public health benefits from reductions in particulate matter- and ozone-related mortality and morbidity, preventing about 12,600 premature deaths by mid-century in the U.S.

Javadi, Parisa↗
DOE OSTI2020

Patterning Metal Grids for GaAs Solar Cells with Cracked Film Lithography: Quantifying the Cost/Performance Tradeoff

We introduce cracked film lithography (CFL) as a way to reduce the cost of III–V photovoltaics (PV). We spin-coat nanoparticle suspensions onto GaAs thin-film device stacks. The suspensions dry in seconds, forming crack networks that we use as templates through which to electroplate the solar cells’ front metal grids. For the first time, we show that heating the crack template allows it to flow and refill cracks, which decreases crack footprint and improves final grid transmittance. We demonstrate 24.7%-efficient single-junction GaAs solar cells using vacuum-free CFL grids. These devices are only 1.7% (absolute) less efficient than the baseline grids patterned by photolithography with the loss mostly resulting from the reduced transparency of the CFL pattern. Additional optimization could decrease this difference. Initial cost modeling suggests that CFL is more scalable than photolithography: In particular, CFL’s lower materials and equipment costs could greatly reduce the levelized cost of electricity of III–V PV at scale, a potential step toward terrestrial deployment.

14 SOLAR ENERGY↗
DOE OSTI2026

Crossover as Determinant for Safety and Performance Tradeoffs in Proton Exchange Membrane Water Electrolyzers

Hydrogen (H2) crossover is a pressing challenge constraining safe and efficient operation of proton exchange membrane water electrolyzers (PEMWEs) especially amongst strides to employ thinner membranes, which enables improved energy efficiency, and elevated cathode pressures, that reduces the energy burden on downstream compressors. Here, we develop a microstructure-aware multicomponent reactive-transport framework that resolves dissolved and gaseous H2 transport pathways and mechanistically links electrode architecture to crossover related safety and performance. We show that operability is co-governed by the cathode catalyst layer (CCL) and the anode porous transport layer (APTL) which sets the H2 crossover flux and the egress capacity respectively. Elevated Pt/C ratio in the CCL suppresses crossover flux by up to 23% while a higher APTL porosity lowers H2 in O2 fraction by 0.6% in the anode effluent. We condense the findings into (cathode pressure-current density) maps overlaid with safety limits and performance targets and ultimately define two safety-performance unified metrics to gauge the size and quality of the operating window. Given the push towards higher pressure and deeper turndown for renewable integration, this study provides mechanistic design guidance to prevent crossover-induced safety risks while preserving the desired performance.

Electrolysis↗
DOE OSTI2025

Addressing genome scale design tradeoffs in Pseudomonas putida for bioconversion of an aromatic carbon source

Genome-scale metabolic models (GSMM) are commonly used to identify gene deletion sets that result in growth coupling and pairing product formation with substrate utilization and can improve strain performance beyond levels typically accessible using traditional strain engineering approaches. However, sustainable feedstocks pose a challenge due to incomplete high-resolution metabolic data for non-canonical carbon sources required to curate GSMM and identify implementable designs. Here we address a four-gene deletion design in the Pseudomonas putida KT2440 strain for the lignin-derived non-sugar carbon source, p-coumarate (p-CA), that proved challenging to implement. We examine the performance of the fully implemented design for p-coumarate to glutamine, a useful biomanufacturing intermediate. In this study glutamine is then converted to indigoidine, an alternative sustainable pigment and a model heterologous product that is commonly used to colorimetrically quantify glutamine concentration. Through proteomics, promoter-variation, and growth characterization of a fully implemented gene deletion design, we provide evidence that aromatic catabolism in the completed design is rate-limited by fumarase hydratase (FUM) enzyme activity in the citrate cycle and requires careful optimization of another fumarate hydratase protein (PP_0897) expression to achieve growth and production. A double sensitivity analysis also confirmed a strict requirement for fumarate hydratase activity in the strain where all genes in the growth coupling design have been implemented. Metabolic cross-feeding experiments were used to examine the impact of complete removal of the fumarase hydratase reaction and revealed an unanticipated nutrient requirement, suggesting additional functions for this enzyme. While a complete implementation of the design was achieved, this study highlights the challenge of completely inactivating metabolic reactions encoded by under-characterized proteins, especially in the context of multi-gene edits.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Tradeoffs in single stage drift step recovery diode generator design

A high-voltage generator of nanosecond pulses utilizing a drift step recovery diode (DSRD) as an opening switch in the compression section is designed to operate at peak voltages of 4 kV and repetition rates of 2 MHz in burst mode at reduced voltages. The generator is used to perform empirical studies on the output metrics of a DSRD generator with a focus on matching the circuit of the reverse current loop parameters and DSRD to the load. The dynamic impedance introduced by nonlinear elements in the DSRD was investigated with respect to the driving circuit by varying the number of DSRDs connected in series. Experimental results indicate that optimization of the driving circuit for the DSRD is key to minimizing losses and achieving optimal pulse compression. Furthermore, the results also indicate trends in DSRD performance as larger storage inductances and longer pumping times are used, limiting the pulse compression capabilities of a single stage DSRD generator.

Electrical properties and parameters↗