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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 OSTI2023

Near-Term Electricity Requirement and Emission Implications for Sustainable Aviation Fuel Production with CO 2 -to-Fuels Technologies

Aviation contributed approximately 10% of the U.S. transportation sector's greenhouse gas (GHG) emissions and about 3% of the nation's total GHG production before the coronavirus disease (COVID-19) pandemic (EPA 2022). Unlike the ground transportation sector, which can be decarbonized by using batteries and hydrogen fuel cell powertrain technologies, the technical and economic challenges of aviation electrification open the opportunity for CO 2 utilization (CO2U) using clean power sources. The U.S. government set a goal to produce 3 billion gallons per year of sustainable aviation fuels (SAF) by 2030 and scale up the production to 35 billion gallons per year by 2050 (Bioenergy Technologies Office 2022). In this report, we examine three potential locations, in California, Iowa, and Louisiana, for SAF production using two production pathways that are expected to be available by 2030. We analyze the electricity cost to satisfy 10% of the SAF production potential for the select locations. Specifically, we consider (1) retail electricity cost from the default local utility in each location; (2) physical power purchase agreement (PPA) for renewable power and battery storage hybrid systems with preset prices; (3) financial PPA from a dedicated renewable plant; and (4) estimated real-time pricing (RTP) from the wholesale power market with utility delivery adders. Retail rates are available for the three potential locations; however, the developer should negotiate with the local utility in Iowa for new tariff riders, because the load of the proposed SAF plant (1.4 GW) is significantly higher than the current industrial tariff structure requirement (200 kW). The developers are not able to claim federal credits (i.e., the Inflation Reduction Act of 2022) when sourcing electricity from local utilities. Developers could consider prioritizing physical and financial PPAs as purchase options. While physical PPAs can be imported out of state, this structure imposes availability issues as developers must locate in the same electricity grid regions. Financial PPAs do not have the same location restrictions and provide the same cost savings as physical PPAs, but financial PPAs impose financial risks in the event of system curtailment and grid interruption. RTPs are available for customers in California with flexible load and hourly load management capability; however, utilities in our studied regions in Louisiana and Iowa only offer time-of-use and curtailment programs to incentivize lower energy usage in peak hours. These utilities do not currently offer RTP programs, and the developer may need to have further negotiations with the local utilities to access RTP programs. The results show that purchased electricity prices may range from 2.6 cents/kWh to 7.1 cents/kWh for the three studied plants.

02 PETROLEUM↗
DOE OSTI2022

Pathways to a Sustainable Aviation Ecosystem: Electrified Aviation Demand Modeling

With leading energy experts, high-performance computing, and powerful analysis and modeling capabilities, the National Renewable Energy Laboratory (NREL) empowers aviation stakeholders with tools and data to project future energy demand and explore supply options. As a result, NREL can help electric utilities and airport operations identify aviation electrification opportunities and prepare for future electricity needs.

aerial vehicles↗
DOE OSTI2021

Surface Modification of Nickel-Rich Cathode Materials by Ionically Conductive Materials at Room Temperature

Nickel-rich cathode materials (LiNi x Mn y Co 1-x-y O 2 , NMC) are promising to push the limits of lithium-ion batteries to higher energy density. This approach is favored in practical applications including electric vehicles and aviation transportation. However, the instability of the NMC at charged state results in safety concerns and poor cycling stability. Surface coating is a practical and effective strategy to address this. Cubic Li7La3Zr2O12 (LLZO) is an ideal coating material regarding the low electron transfer rate and high Li+ conductivity. Thus, a LLZO coating layer can suppress the parasitic reactions in the electrode/electrolyte interface without deteriorating the lithium migration. However, high-temperature calcination seems to inevitably create the chemical couplings between NMC and LLZO, leading to the interdiffusion and degradation of NMC and LLZO crystal structures. This work presents a simple mechanochemical method to effectively coat LLZO on the NMC particle surface. Furthermore, the coated cathode demonstrates superior electrochemical performance compared with the pristine NMC cathode.

25 ENERGY STORAGE↗
DOE OSTI2024

Ligand-channel-enabled ultrafast Li-ion conduction

Li-ion batteries (LIBs) for electric vehicles and aviation demand high energy density, fast charging and a wide operating temperature range, which are virtually impossible because they require electrolytes to simultaneously have high ionic conductivity, low solvation energy and low melting point and form an anion-derived inorganic interphase. We report guidelines for designing such electrolytes by using small-sized solvents with low solvation energy. The tiny solvent in the secondary solvation sheath pulls out the Li + in the primary solvation sheath to form a fast ion-conduction ligand channel to enhance Li + transport, while the small-sized solvent with low solvation energy also allows the anion to enter the first Li + solvation shell to form an inorganic-rich interphase. The electrolyte-design concept is demonstrated by using fluoroacetonitrile (FAN) solvent. The electrolyte of 1.3 M lithium bis(fluorosulfonyl)imide (LiFSI) in FAN exhibits ultrahigh ionic conductivity of 40.3 mS cm -1 at 25 °C and 11.9 mS cm -1 even at -70 °C, thus enabling 4.5-V graphite||LiNi 0.8 Mn 0.1 Co 0.1 O 2 pouch cells (1.2 Ah, 2.85 mAh cm -2 ) to achieve high reversibility (0.62 Ah) when the cells are charged and discharged even at -65 °C. The electrolyte with small-sized solvents enables LIBs to simultaneously achieve high energy density, fast charging and a wide operating temperature range, which is unattainable for the current electrolyte design but is highly desired for extreme LIBs. This mechanism is generalizable and can be expanded to other metal-ion battery electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2025

Quantitative insights for diagnosing performance bottlenecks in lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries hold significant promise for electric vehicles and aviation due to their high energy density and cost-effectiveness. However, understanding the root causes of performance degradation remains a formidable challenge, as the interplay of multiple factors obscures key failure mechanisms. A major limitation has been the inability to quantify soluble sulfur species within practical detection limits accurately and to correlate electrochemical processes with associated physical inventory changes. Here, we introduce the high-performance liquid chromatography-ultraviolet spectroscopy and gas chromatography sequential characterization (HUGS) toolkit, capable of precisely quantifying seven distinct sulfur and polysulfide species at concentrations as low as 40 ppb. HUGS has been successfully applied to practical coin and pouch cells without requiring cell modification. Furthermore, our self-developed software, Dr HUGS, enhanced the data analysis speed by over 30 times, enabling multi-source data integration and delivering comprehensive analysis results within minutes. Using HUGS, we identify significant capacity losses from inactive lithium and sulfur during initial cycles and sulfide-rich solid–electrolyte interphase (SEI) formation on the anode during later cycles. Notably, our findings reveal that soluble polysulfides have minimal contributions to capacity loss, challenging long-standing assumptions. Moreover, HUGS demonstrates that constant-pressure setups in Li–S pouch cells improve compositional uniformity compared to constant-gap configurations. For sulfurized polyacrylonitrile (SPAN) cathodes, unique issues such as non-sulfide SEI formation and lithium pulverization are observed, which can be mitigated through localized high-concentration electrolytes to enhance lithium inventory retention. By enabling precise quantification of critical inventory components, HUGS provides transformative insights into failure mechanisms across various electrolytes and cathode chemistries, guiding rational design strategies for next-generation energy storage systems.

25 ENERGY STORAGE↗
DOE OSTI2023

Ampaire ARPA-e Electric Flight Testbed

A hybrid-electric aircraft flying testbed was developed in this program with the intent to serve as a dedicated, enduring testbed to test and evaluate ARPA-e CIRCUITS Program and other electrified aviation technologies in relevant flight environments. This testbed enabled rapid development cycles of novel and innovative technologies in the electrified aviation space, maturing them from a research lab environment to flying in an aircraft. By providing research groups with the means to test their transformative technologies in a real-world, aircraft environment, the path to validating the safety and reliability of their technologies for future commercial opportunities was greatly accelerated. Three core technologies were integrated and tested: an inverter/motor drive built by the University of Arkansas, a solid-state circuit breaker (iBreaker) built by the Illinois Institute of Technology, and a Flying Capacitor Multi-level (FCML) DC/DC converter built by the University of California, Berkeley. In each of these cases, the requirements established for safety of flight resulted in a holistic approach to the designs, evoking a deeper understanding of the potential failure modes and mitigations necessary to build a robust and flightworthy system. Further, the integration into a hybrid-electric aircraft de-risked the potential electrical and mechanical issues that cannot easily be experienced or replicated in a lab environment. The experiments were also required to undergo representative temperature, shock, and vibration testing as the FAA prescribes for this category of aircraft, facilitating familiarity with the relevant design and test guidelines necessary to commercialize the technologies. This testbed unlocks the massive potential of core power electronics technologies necessary for a safe, robust, and efficient electric aviation future. With quick iterative design, test, and flight cycles, these core technologies are on a quicker path to technology readiness level maturity and commercialization, enabling a more sustainable future for the aviation industry.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Annual Technology Baseline: The 2022 Transportation Update [Slides]

The Transportation Annual Technology Baseline (ATB) provides detailed cost and performance data, estimates, and assumptions for vehicle and fuel technologies in the United States. It includes current and projected estimates for vehicle technologies as well as conventional and alternative fuels, and it details the assumptions used to calculate those costs, such as gas and electricity prices, discount rates, and vehicle miles traveled. The 2022 update added more classes of light-duty vehicles, medium and heavy-duty vehicles, an aviation page, and it aligned diesel pathways with aviation pathways.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

High Power Density, Carbon Neutral Electrical Power Generation for Air Vehicles

The synergistic integration of a Solid Oxide Fuel Cell-Combustor (SOFC-C) with a turbogenerator (TG) will provide a very high fuel-to-electricity conversion efficiency while maintaining high power-to-weight ratio during high-altitude flight. The proposed SOFC-C-TG power generation technology exceeds the REEACH technical performance targets (TPT). This unique concept addresses many of the challenges faced in all electric propulsion-based aviation. The system has high part-load efficiency (more than 65% lower heating value (LHV)) during long cruise times, load following capability, high-power capacity at high altitudes adapting to low temperatures and pressures, rapid startup time of less than 30 minutes (proven with current SOFC technology), high power density (more than 3.2 kW/kg), efficient thermal management, and a foundation for a compact, efficient electrical storage and power generation system (ESPG). The SOFC-C concept achieves the technology targets by reducing the complexity of traditional fuel cell-gas turbine hybrid systems (FC-GT). The SOFC-C does not require heat exchangers and dramatically reduces the balance of plant increasing power density and performance in efficiency. The reduction in mass through elimination of heat exchangers, external reformer, and other components dramatically decreases the overall thermal dampening of the system which enables rapid startup and load following capability. Direct control of the cathode inlet temperature of the SOFC-C enables rapid warm-up of the SOFC tubes with the ability to reach operating temperature and full power in less than 30 minutes.

03 NATURAL GAS↗
DOE OSTI2024

Annual Technology Baseline (ATB): The 2024 Transportation Update

The Transportation Annual Technology Baseline (ATB) provides detailed cost and performance data, estimates, and assumptions for vehicle and fuel technologies in the United States. It includes current and projected estimates for vehicle technologies as well as fuels, and it details the assumptions used to calculate those costs, such as gas and electricity prices, discount rates, and vehicle miles traveled. The 2024 update added more biofuels pathways to align with pathways used in the Biomass Scenario Model.

ADVANCED PROPULSION SYSTEMS,DIRECT ENERGY CONVERSI↗
DOE OSTI2021

Challenges and needs for system-level electrochemical lithium-ion battery management and diagnostics

The desire for energy-dense and fast-charged battery technology in consumer-electronics, electric-vehicle, grid, and aviation applications is pushing the envelope on materials to cells and pack designs to use and operating conditions. However, some approaches could inherently decrease safety of the battery—thus requiring the development of advanced management and diagnostics. Safety of lithium-ion batteries (LiBs), particularly in multicell configurations, is highly variable and could evolve with use. Existing works primarily focus on cell life and safety diagnostics without considering module and pack-level uncertainties and sometimes imply that cell-level electrochemical diagnostics would work in modules or packs, a naive oversimplification. Using example case studies, we highlight the potential and challenges associated with extending single-cell diagnostics to multiple cells, note the challenge involved, and motivate the research and development and support communities to devote efforts to fill the gap by developing diagnostics at these levels for current- and future-generation LiBs.

25 ENERGY STORAGE↗
DOE OSTI2020

Energy storage emerging: A perspective from the Joint Center for Energy Storage Research

Energy storage is an integral part of modern society. A contemporary example is the lithium (Li)-ion battery, which enabled the launch of the personal electronics revolution in 1991 and the first commercial electric vehicles in 2010. Most recently, Li-ion batteries have expanded into the electricity grid to firm variable renewable generation, increasing the efficiency and effectiveness of transmission and distribution. Important applications continue to emerge including decarbonization of heavy-duty vehicles, rail, maritime shipping, and aviation and the growth of renewable electricity and storage on the grid. This perspective compares energy storage needs and priorities in 2010 with those now and those emerging over the next few decades. The diversity of demands for energy storage requires a diversity of purpose-built batteries designed to meet disparate applications. Advances in the frontier of battery research to achieve transformative performance spanning energy and power density, capacity, charge/discharge times, cost, lifetime, and safety are highlighted, along with strategic research refinements made by the Joint Center for Energy Storage Research (JCESR) and the broader community to accommodate the changing storage needs and priorities. Innovative experimental tools with higher spatial and temporal resolution, in situ and operando characterization, first-principles simulation, high throughput computation, machine learning, and artificial intelligence work collectively to reveal the origins of the electrochemical phenomena that enable new means of energy storage. This knowledge allows a constructionist approach to materials, chemistries, and architectures, where each atom or molecule plays a prescribed role in realizing batteries with unique performance profiles suitable for emergent demands.

Trahey, Lynn↗
DOE OSTI2024

Pathways to a Sustainable Aviation Ecosystem: Aviation Energy Research and Operation Simulator (AEROSim)

The National Renewable Energy Laboratory (NREL) has developed highly accessible tools for ground vehicle modeling, making it easy to quickly compare powertrains and estimate the impact of technology improvements on fuel/energy consumption, performance, cost, and battery life. With AEROSim, NREL advanced aircraft, enabling the same level of ease and versatility in comparing aircraft designs across a range of scenarios and conditions.

advanced air mobility↗
DOE OSTI2021

Electrification of Aircraft: Challenges, Barriers, and Potential Impacts

Small-scale aircraft are being electrified with small e-aircraft already certified to fly and with test flights underway for retrofits of existing aircraft focused on near-term deployment. Internationally, from 2018 to 2020, the number of electric aircraft projects underway increased 50%. These technologies are projected to increase operational efficiency and reduce emissions and noise from a growing aviation sector. This emerging interest in aviation electrification includes aircraft, energy supply equipment, and battery storage manufacturers. Federal agencies are currently funding a variety of efforts including technology research as well as forecasting demand and environmental impacts and state governments have also begun pushing for further investigation in this area. This paper provides an overview of the current state and potential future development of aviation electrification. To understand the types of research questions around current and future challenges for this emerging sector, we consider a case study of the potential deployment of small commercial electric aircraft for existing, under-served markets and consider operational requirements and technical challenges as well as the range of questions that will need to be addressed around charging infrastructure, grid integration, policy and regulatory requirements, and emissions impacts. This case study also outlines potential nearer-term solutions and research areas of interest that will need to be addressed in the longer term at much larger scales and highlights NREL capabilities for addressing these challenges.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Study of eVTOL Charging Impact on Airport Electrical Grids

Growth in commercial air traffic has increased the aviation industry's contribution to global emissions. Aircraft electrification can reduce greenhouse gas emissions along with being efficient and reliable. Advanced air mobility introduces the idea of an advanced and more efficient air transportation system. Electric and hybrid aircraft designs, such as electric vertical takeoff and landing (eVTOL), are being considered for a number of applications, such as urban air mobility, cargo delivery, and medical emergencies. Although the electrification of aircraft provides environmental benefits, their charging needs will place significant demand on the electrical grid. This work presents a grid impact study and infrastructure upgrade requirements analysis of eVTOL charging on a realistic distribution grid through power flow simulation analysis. The case study results show that the eVTOL charging can lead to power quality issues, such as undervoltage and equipment capacity overloading. Grid infrastructure, such as lines and transformers, would need to be upgraded, and voltage management strategies would need to be deployed to accommodate eVTOL charging at an existing airport.

advanced air mobility (AAM)↗
DOE OSTI2023

Quantitative approaches for including equity in risk and resilience infrastructure planning analyses

Risk and resilience assessments for critical infrastructure focus on myriad objectives, from natural hazard evaluations to optimizing investments. Although research has started to characterize externalities associated with current or possible future states, incorporation of equity priorities at project inception is increasingly being recognized as critical for planning related activities. However, there is no standard methodology that guides development of equity-informed quantitative approaches for infrastructure planning activities. Here, to address this gap, we introduce a logic model that can be tailored to capture nuances about specific geographies and community priorities, effectively incorporating them into different mathematical approaches for quantitative risk assessments. Specifically, the logic model uses a graded, iterative approach to clarify specific equity objectives as well as inform the development of equations being used to support analysis. We demonstrate the utility of this framework using case studies spanning aviation fuel, produced water, and microgrid electricity infrastructures. For each case study, the use of the logic model helps clarify the ways that local priorities and infrastructure needs are used to drive the types of data and quantitative methodologies used in the respective analyses. The explicit consideration of methodological limitations (e.g., data mismatches) and stakeholder engagements serves to increase the transparency of the associated findings as well as effectively integrate community nuances (e.g., ownership of assets) into infrastructure assessments. Such integration will become increasingly important to ensure that planning activities (which occur throughout the lifecycle of the infrastructure projects) lead to long-lasting solutions to meet both energy and sustainable development goals for communities.

community-based↗
DOE OSTI2022

Building a Sustainable Aviation Brain Trust: Key Insights From the 2022 NREL Partner Forum

Cross-sector collaboration is key for guiding the large, complex aviation industry over the emissions peak and quickly down the slope to net-zero - that theme was repeated regularly during the two-day 2022 NREL Partner Forum. With an expanding global economy, more people than ever want the convenience of air travel. That has made aviation the fastest-growing transportation sector, as well as a rising source of carbon emissions. How can the industry serve its customers while charting a course to net-zero in line with climate goals? Interest and momentum from public and private sectors are mounting to answer that question, a backdrop for the Partner Forum. The National Renewable Energy Laboratory (NREL) brought 200 attendees to the whiteboard to find common goals, align interests, understand technologies, and discuss steps for safely and seamlessly decarbonizing aviation. This document captures the tenor of the conversations and provides a summary of the 1.5 day event for those who were not able to attend or who have interest in this area.

aircraft↗
DOE OSTI2026

What Is the Best Use of Biomass? A Harmonized LCA-TEA Framework Quantifying Economic and Environmental Metrics for Bioenergy Pathways

Bioresource utilization is expected to play a pivotal role in complementing existing energy pathways and enhancing energy resilience. This study develops a harmonized life cycle assessment (LCA) and techno-economic analysis (TEA) framework to evaluate the greenhouse gas (GHG) reduction potential, minimum fuel selling price (MFSP), and marginal abatement cost (MAC) of bioenergy pathways. We analyze 19 pathways, including liquid biofuels (via catalytic fast pyrolysis, Fischer–Tropsch synthesis, and gasification), bioelectricity, and biomass-to-hydrogen, with and without carbon capture and storage (CCS). The GHG impacts are assessed using the GREET 2022 model, while U.S. Billion-Ton 2016 biomass availability projections are used to estimate scale-up potential. Additionally, we evaluate the influence of a low-carbon electricity grid on pathway performance. Our results show that CCS implementation reduces carbon intensities (CI) to net-negative values for several pathways, with MAC ranging from $\$$32 to $\$$600 per metric ton (MT) CO2e avoided. Bioelectricity pathways with CCS achieve the lowest MAC ($\$$32–$\$$68/tCO2e), while liquid biofuels and hydrogen pathways remain critical for hard-to-abate sectors like aviation and heavy industry. Pathways with net-positive electricity demand benefit from a low-carbon grid, whereas those co-producing electricity experience increased MAC under lower electricity grid CI scenarios. This open-source framework provides a robust tool for harmonized evaluation of bioenergy pathways, enabling policymakers and stakeholders to identify cost-effective strategies for biomass utilization and carbon abatement at scale. The findings underscore the importance of CCS, co-product credits, and feedstock availability in optimizing bioenergy deployment for a low-carbon economy.

09 BIOMASS FUELS↗