Search NASA⌕ Search

SEARCH · Search NASA

Results for “Capacity Factor”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Physicochemical Behavior of Penaeuse semisulcatuse Chitin for Pb and Cd Removal from Aqueous Environment

A beta type-chitin was produced from the shell of Penaeuse semisulcatuse shrimp for removal of lead and cadmium from the aqueous environment. Full physicochemical properties of the chitin (FTIR, SEM, mapping, XRD, EDX, AFM, and TGA-DTG) were obtained. Effects of solution pH, chitin dose, metals concentration, and contact time on the lead and cadmium adsorption were assessed. The solution pH had a great influence on the metal removal. Pseudo-first and pseudo-second order models were used to evaluate the kinetic behavior of metals adsorption by P. semisulcatuse chitin. Freundlich isotherm model was slightly better than the Langmuir model to describe the adsorption data. The R{sub L} value (obtained from the Langmuir model) for the adsorption of lead and cadmium was calculated to be 0.027 and 0.133, respectively, which showed the metals adsorption process by the chitin is desirable. The maximum adsorption capacity of lead and cadmium by P. semisulcatuse chitin was determined 13.14 mg/g and 19.15 mg/g, respectively. To desorb the adsorbed-metal from the chitin, the 1M HNO{sub 3} solution was applied and the heavy metals desorption was suitable (90%). The half life (t{sub 1/2}) factor in the adsorption of Pb and Cd onto chitin was calculated 2.817 min and 3.876 min, respectively.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

How are coastal households responding to climate change?

In Australia, shared responsibility is a concept advocated to promote collective climate change adaptation by multiple actors and institutions. However, a shared response is often promoted in the absence of information regarding actions currently taken; in particular, there is limited knowledge regarding action occurring at the household scale. To address this gap, we examine household actions taken to address climate change and associated hazards in two Australian coastal communities. Mixed methods research is conducted to answer three questions: (1) what actions are currently taken (mitigation, actions to lobby for change or adaptation to climate impacts)? (2) why are these actions taken (e.g. are they consistent with capacity, experience, perceptions of risk); and (3) what are the implications for adaptation? We find that households are predominantly mitigating greenhouse gas emissions and that impact orientated adaptive actions are limited. Coping strategies are considered sufficient to mange climate risks, proving a disincentive for additional adaptive action. Influencing factors differ, but generally, risk perception and climate change belief are associated with action. Furthermore, the likelihood of more action is a function of homeownership and a tendency to plan ahead. Addressing factors that support or constrain household adaptive decision-making and action, from the physical (e.g. homeownership) to the social (e.g. skills in planning and a culture of adapting to change) will be critical in increasing household participation in adaptation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Optimal Methanol Production via Sorption-Enhanced Reaction Process

To counter the equilibrium limitations in traditional methanol production from synthesis gas, a periodic and sorption-enhanced methanol synthesis process (SE-MeOH) with in situ removal of water byproduct is designed and optimized. A generalized reaction–adsorption modeling and simulation framework is coupled with a simulation-based constrained gray-box optimizer to obtain the optimal cycle configuration, design parameters, process specifications, and operating conditions. The best-case results indicate that SE-MeOH processes can break the barrier of the current limit of industrial methanol yield and improve it by 55–87% with a slight compromise (9–46%) on CH 3 OH production capacity. This trade-off is a result of periodic operation which is required for sorption enhancement. The techno-economic optimization of a base industrial reactor also leads to more than 7% improvement in methanol yield with only 2% decrease in production capacity while keeping the cost of syngas-to-methanol production competitive. The SE-MeOH system is further optimized through varying the feed specifications and number of reactor tubes. Furthermore, the results suggest that the synthesis gas composition, flow rate, and number of tubes are the major factors in determining methanol process performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Geometric alignment of aminoacyl-tRNA relative to catalytic centers of the ribosome underpins accurate mRNA decoding

Accurate protein synthesis is determined by the two-subunit ribosome’s capacity to selectively incorporate cognate aminoacyl-tRNA for each mRNA codon. The molecular basis of tRNA selection accuracy, and how fidelity can be affected by antibiotics, remains incompletely understood. Using molecular simulations, we find that cognate and near-cognate tRNAs delivered to the ribosome by Elongation Factor Tu (EF-Tu) can follow divergent pathways of motion into the ribosome during both initial selection and proofreading. Consequently, cognate aa-tRNAs follow pathways aligned with the catalytic GTPase and peptidyltransferase centers of the large subunit, while near-cognate aa-tRNAs follow pathways that are misaligned. These findings suggest that differences in mRNA codon-tRNA anticodon interactions within the small subunit decoding center, where codon-anticodon interactions occur, are geometrically amplified over distance, as a result of this site’s physical separation from the large ribosomal subunit catalytic centers. These insights posit that the physical size of both tRNA and ribosome are key determinants of the tRNA selection fidelity mechanism.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Social-ecological interactions in a disaster context: Puerto Rican farmer households’ food security after Hurricane Maria

Islands are uniquely vulnerable to extreme weather events and food insecurity, and have additional response challenges due to their limited landmasses and economies, isolation, colonial legacies, and high dependence of food imports. Domestic farmers have a key role in producing food for island communities like Puerto Rico, which can safeguard food security when food importation may be challenging. Nevertheless, in the context of disaster, farmers themselves may be vulnerable to food insecurity and unable to contribute to domestic markets. This paper examines Puerto Rican farmers households’ food security in the aftermath of 2017’s Hurricane Maria using a social-ecological lens. Survey data from 405 farmers gathered eight months after Maria, coupled with biophysical data from the hurricane’s impacts (winds, rains, and landslides), were analyzed. Overall, 69% of farmers experienced at least one month of food insecurity in the aftermath of Hurricane Maria, and 38% reported persistent food insecurity (three months or more). A multinomial logistic regression suggests that biophysical impacts, but especially social factors, such as age and constraint access to external sources of support, are linked with persistent food insecurity. This suggests that the biophysical impacts of the hurricane interact with existing infrastructure and social resources to affect farmer vulnerability and the food environment in different ways. Thus, strengthening adaptive capacity in multiple domains can help farmers and vulnerable populations better navigate the disruptions faced during disasters to alleviate food insecurity.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Fast Charge-Driven Li Plating on Anode and Structural Degradation of Cathode

Enabling fast charging in lithium ion batteries (LIBs) is a key factor to make electric vehicles drive just like gasoline-powered vehicles when the time comes to refuel. However, fast charging to current LIBs (LiNi x Mn y Co 1–z O 2 /graphite) is limited by lithium plating, which is barely reversible and causes LIBs to lose capacity over time. Thus, research to quantify the lithium plating in LIB cells is extremely important in improving our fundamental understanding of lithium plating behavior and enabling fast charging for LIBs. Here, we precisely quantified the amount of fast-charge-driven lithium plating in a coin-cell composed of LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532)/graphite. We found that the amount of lithium plating gradually increases with the cycle count and reaches 25.59 μmole (26.80 mAh g –1 cathode ) by the 100th cycle. The study also reveals that the NMC532 has lost 19% of its original lithium content after 100 fast-charging cycles; this, correspondingly, causes a lattice volumetric strain of 0.59%.

25 ENERGY STORAGE↗
DOE OSTI2015

A User Guide to PARET/ANL (V.7.6) (Rev.1)

PARET was originally created in 1969 at what is now Idaho National Laboratory (INL), to analyze reactivity insertion events in research and test reactor cores cooled by light or heavy water, with fuel composed of either plates or pins. The use of PARET is also appropriate for fuel assemblies with curved fuel plates when their radii of curvatures are large with respect to the fuel plate thickness. The PARET/ANL version of the code has been developed at Argonne National Laboratory (ANL) under the sponsorship of the U.S. Department of Energy/NNSA, and has been used by the Reactor Conversion Program to determine the expected transient behavior of a large number of reactors. PARET/ANL models the various fueled regions of a reactor core as channels. Each of these channels consists of a single flat fuel plate/pin (including cladding and, optionally, a gap) with water coolant on each side. In slab geometry the coolant channels for a given fuel plate are of identical dimensions (mirror symmetry), but they can be of different thickness in each channel. There can be many channels, but each channel is independent and coupled only through reactivity feedback effects to the whole core. The time-dependent differential equations that represent the system are replaced by an equivalent set of finite-difference equations in space and time, which are integrated numerically. PARET/ANL uses fundamentally the same numerical scheme as RELAP5 for the time-integration of the point-kinetics equations. The one-dimensional thermal-hydraulic model includes temperature-dependent thermal properties of the solid materials, such as heat capacity and thermal conductivity, as well as the transient heat production and heat transfer from the fuel meat to the coolant. Temperature- and pressure-dependent thermal properties of the coolant such as enthalpy, density, thermal conductivity, and viscosity are also used in determining parameters such as friction factors and heat transfer coefficients. The code first determines the steady-state solution for the initial state. Then the solution of the transient is obtained by integration in time and space. Multiple heat transfer, DNB and flow instability correlations are available. The code was originally developed to model reactors cooled by an open loop, which was adequate for rapid transients in pool-type cores. An external loop model appropriate for Miniature Neutron Source Reactors (MNSR’s) was also added to PARET/ANL to model natural circulation within the vessel, heat transfer from the vessel to pool and heat loss by evaporation from the pool. PARET/ANL also contains models for decay heat after shutdown, control rod reactivity versus time or position, time-dependent pump flow, and loss-of-flow event with flow reversal as well as logic for trips on period, power, and flow. Feedback reactivity effects from coolant density changes and temperature changes are represented by tables. Feedback reactivity from fuel heat-up (Doppler Effect) is represented by a four-term polynomial in powers of fuel temperature. Photo-neutrons produced in beryllium or in heavy water may be included in the point-kinetics equations by using additional delayed neutron groups.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

A User Guide to PARET/ANL

PARET was originally created in 1969 at what is now Idaho National Laboratory (INL), to analyze reactivity insertion events in research and test reactor cores cooled by light or heavy water, with fuel composed of either plates or pins. The use of PARET is also appropriate for fuel assemblies with curved fuel plates when their radii of curvatures are large with respect to the fuel plate thickness. The PARET/ANL version of the code has been developed at Argonne National Laboratory (ANL) under the sponsorship of the U.S. Department of Energy/NNSA since the inception of the Reactor Conversion Program. Since Reduced Enrichment for Research and Test Reactors (RERTR) began in 1978, PARET/ANL has been benchmarked to experimental data including SPERT testing, and used to determine the expected transient behavior of a large number of reactors regardless of enrichment both inside and outside the Reactor Conversion Program. This document provides the pertinent information for the use of PARET/ANL Version 7.6. PARET/ANL models the various fueled regions of a reactor core as channels. Each of these channels consists of a single flat fuel plate/pin (including cladding and, optionally, a gap) with water coolant on each side. In slab geometry the coolant channels for a given fuel plate are of identical dimensions (mirror symmetry), but they can be of different thickness in each channel. There can be many channels, but each channel is independent and coupled only through reactivity feedback effects to the whole core. The time-dependent differential equations that represent the system are replaced by an equivalent set of finite-difference equations in space and time, which are integrated numerically. PARET/ANL uses fundamentally the same numerical scheme as RELAP5 for the time-integration of the point-kinetics equations. The one-dimensional thermal-hydraulic model includes temperature-dependent thermal properties of the solid materials, such as heat capacity and thermal conductivity, as well as the transient heat production and heat transfer from the fuel meat to the coolant. Temperature- and pressure-dependent thermal properties of the coolant such as enthalpy, density, thermal conductivity, and viscosity are also used in determining parameters such as friction factors and heat transfer coefficients. The code first determines the steady-state solution for the initial state. Then the solution of the transient is obtained by integration in time and space. Multiple heat transfer, DNB and flow instability correlations are available. The code was originally developed to model reactors cooled by an open loop, which was adequate for rapid transients in pool-type cores. An external loop model appropriate for Miniature Neutron Source Reactors (MNSR’s) was also added to PARET/ANL to model natural circulation within the vessel, heat transfer from the vessel to pool and heat loss by evaporation from the pool. PARET/ANL also contains models for decay heat after shutdown, control rod reactivity versus time or position, time-dependent pump flow, and loss-of-flow event with flow reversal as well as logic for trips on period, power, and flow. Feedback reactivity effects from coolant density changes and temperature changes are represented by tables. Feedback reactivity from fuel heat-up (Doppler Effect) is represented by a four-term polynomial in powers of fuel temperature. Photo-neutrons produced in beryllium or in heavy water may be included in the point-kinetics equations by using additional delayed neutron groups.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

A User Guide to PARET/ANL

PARET was originally created in 1969 at what is now Idaho National Laboratory (INL), to analyze reactivity insertion events in research and test reactor cores cooled by light or heavy water, with fuel composed of either plates or pins. The use of PARET is also appropriate for fuel assemblies with curved fuel plates when their radii of curvatures are large with respect to the fuel plate thickness. The PARET/ANL version of the code has been developed at Argonne National Laboratory (ANL) under the sponsorship of the U.S. Department of Energy/NNSA since the inception of the Reactor Conversion Program. Since Reduced Enrichment for Research and Test Reactors (RERTR) began in 1978, PARET/ANL has been benchmarked to experimental data including SPERT testing, and used to determine the expected transient behavior of a large number of reactors regardless of enrichment both inside and outside the Reactor Conversion Program. This document provides the pertinent information for the use of PARET/ANL Version 7.6. PARET/ANL models the various fueled regions of a reactor core as channels. Each of these channels consists of a single flat fuel plate/pin (including cladding and, optionally, a gap) with water coolant on each side. In slab geometry the coolant channels for a given fuel plate are of identical dimensions (mirror symmetry), but they can be of different thickness in each channel. There can be many channels, but each channel is independent and coupled only through reactivity feedback effects to the whole core. The time-dependent differential equations that represent the system are replaced by an equivalent set of finite-difference equations in space and time, which are integrated numerically. PARET/ANL uses fundamentally the same numerical scheme as RELAP5 for the time-integration of the point-kinetics equations. The one-dimensional thermal-hydraulic model includes temperature-dependent thermal properties of the solid materials, such as heat capacity and thermal conductivity, as well as the transient heat production and heat transfer from the fuel meat to the coolant. Temperature- and pressure-dependent thermal properties of the coolant such as enthalpy, density, thermal conductivity, and viscosity are also used in determining parameters such as friction factors and heat transfer coefficients. The code first determines the steady-state solution for the initial state. Then the solution of the transient is obtained by integration in time and space. Multiple heat transfer, DNB and flow instability correlations are available. The code was originally developed to model reactors cooled by an open loop, which was adequate for rapid transients in pool-type cores. An external loop model appropriate for Miniature Neutron Source Reactors (MNSR’s) was also added to PARET/ANL to model natural circulation within the vessel, heat transfer from the vessel to pool and heat loss by evaporation from the pool. PARET/ANL also contains models for decay heat after shutdown, control rod reactivity versus time or position, time-dependent pump flow, and loss-of-flow event with flow reversal as well as logic for trips on period, power, and flow. Feedback reactivity effects from coolant density changes and temperature changes are represented by tables. Feedback reactivity from fuel heat-up (Doppler Effect) is represented by a four-term polynomial in powers of fuel temperature. Photo-neutrons produced in beryllium or in heavy water may be included in the point-kinetics equations by using additional delayed neutron groups.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1974

Attitude stability of a flexible solar electric spacecraft - A parametric study

The influence of large area solar array flexibility on the attitude control of a solar electric spacecraft is analyzed. The spacecraft consists of a rigid central body, two flexible roll-out solar arrays, and a cluster of three electric propulsion engines. Each engine has gimballing or translational capacity, or both, for attitude control purposes. A parametric stability study of various spacecraft configurations was made, using hybrid coordinate techniques in an eigenvalue analysis. Parameters varied were solar array aspect ratio, solar array first natural frequency, solar array rotation angle about the yaw axis, and sensor gain factors. Only the first six modes of solar array vibration were included in the study. The attitude response characteristics of the various spacecraft configurations were obtained by means of a digital computer simulation program of the system's equations of motion. The feasibility of using the thrusters for attitude control of electric propulsion spacecraft is demonstrated. It is also shown that although the dynamics effects of large-area flexible solar arrays can be harmful, changes in the control system parameters can insure stable attitude control.

Marsh, E. L.↗
NASA NTRS1974

Thermodynamic properties derived from the free volume model of liquids

An equation of state and expressions for the isothermal compressibility, thermal expansion coefficient, heat capacity, and entropy of liquids have been derived from the free volume model partition function suggested by Turnbull. The simple definition of the free volume is used, and it is assumed that the specific volume is directly related to the cube of the intermolecular separation by a proportionality factor which is found to be a function of temperature and pressure as well as specific volume. When values of the proportionality factor are calculated from experimental data for real liquids, it is found to be approximately constant over ranges of temperature and pressure which correspond to the dense liquid phase. This result provides a single-parameter method for calculating dense liquid thermodynamic properties and is consistent with the fact that the free volume model is designed to describe liquids near the solidification point.

Miller, R. I.↗
DOE OSTI2023

Demarcating the Impact of Electrolytes on High–Nickel Cathodes and Lithium–Metal Anode

The ever-growing demand for low-cost, high-energy-density lithium-ion batteries (LIBs) makes high-nickel layered oxide cathodes, especially LiNiO 2 (LNO), one of the most appealing candidates. However, poor structural and surface instability that leads to a short cycle life remains a formidable challenge. Herein, a systematic investigation of LNO performance in two different electrolytes (a conventional carbonate-based LP57 electrolyte and an ether-based localized high-concentration electrolyte (LHCE)) with different charge cut-off voltages is presented. These findings show that the cathode-electrolyte reactivity is the main factor dictating the performance degradation of LNO at high voltages rather than bulk integrity. While LHCE can provide good stability beyond 4.2 V with a robust, uniform solid–electrolyte interphase (SEI) layer on the Li-metal anode, there is no significant difference in cyclability at 4.15 V (96% capacity retention after 200 cycles) for both LP57 and LHCE. From LNO symmetric cells, carbonate-based electrolyte is found to be good for LNO stability while ether-based electrolyte is beneficial toward Li-metal anode. Furthermore, a suitable electrolyte or a low cut-off voltage is necessary to maintain a decent cycle life. Altogether, this work highlights the impact of electrolyte and cut-off voltage on LNO and Li-metal, which can help guide the development of cells based on LNO.

25 ENERGY STORAGE↗
DOE OSTI2022

Efficient Removal of Lead Ions from Aqueous Media Using Sustainable Sources Based on Marine Algae

The goal of this project is to explore a new method to efficiently remove Pb(II) ions from water by processing Undaria pinnatifida into immobilized beads using sodium alginate and calcium chloride. The resulting biosorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). Using immobilized U. pinnatifida, we investigated the effect of various factors on Pb(II) ion removal efficiency such as temperature, pH, ionic strength, time, and underlying biosorption mechanisms. For Pb(II) ion biosorption studies, Pb(II) ion biosorption data were obtained and analyzed using Langmuir and Freundlich adsorption models. It is found that the maximum Pb(II) ion adsorption capacity (X m ) of U. pinnatifida was estimated to be ~5 times greater than that of activated carbon, indicating the superior Pb(II) ion removal capability of U. pinnatifida compared to activated carbon. In addition, a thermodynamic study indicates that biosorption processes are found to be endothermic and an increase in the Pb(II) ion solution temperature provides a more preferential reaction toward Pb(II) ion biosorption.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Prevalence of LuxR- and LuxI-type quorum sensing circuits in members of the Populus deltoides microbiome

We are interested in the root microbiome of the fast-growing Eastern cottonwood tree, Populus 25 deltoides. There is a large bank of bacterial isolates from P. deltoides and there are 44 draft 26 genomes of bacterial endophyte and rhizosphere isolates. As a first step in efforts to understand 27 the roles of bacterial communication and plant-bacterial signaling in P. deltoides we focused on 28 the prevalence of acyl-homoserine lactone (AHL) quorum sensing signal production and 29 reception in members of the P. deltoides microbiome. We screened 129 bacterial isolates for 30 AHL production using a broad-spectrum bioassay that responds to many but not all AHLs, and 31 we queried the available genome sequences of microbiome isolates for homologs of AHL 32 synthase and receptor genes. AHL signal production was detected in 40% of 129 strains tested. 33 Positive isolates included -, - and -Proteobacteria. Members of the luxI family of AHL 34 synthases were identified in 18 of 39 Proteobacteria genomes including genomes of some 35 isolates that tested negative in the bioassay. Members of the luxR family of transcription factors, 36 that include AHL-responsive factors, were more abundant than luxI homologs. There were 72 in 37 the 39 Proteobacteria genomes. Some of the luxR homologs appear to be members of a 38 subfamily of LuxRs that respond to as yet unknown plant signals rather than bacterial AHLs. 39 Apparently, there is a substantial capacity for AHL cell-to-cell communication in Proteobacteria 40 of the P. deltoides microbiota and there are also Proteobacteria with LuxR homologs of the type 41 hypothesized to respond to plant signals or cues.

Schaefer, Amy L↗
DOE OSTI2018

Hybrid Composite Materials Based on Natural Layered Silicates

We have prepared composite materials based on natural silicates: vermiculite modified with cellulose and nontronite modified with an alkaline rice husk hydrolysate. The materials have been characterized by X-ray diffraction, IR spectroscopy, and positron annihilation spectroscopy, and their specific surface area, sorption capacity (for model dye solutions), and tribological properties have been assessed. It has been shown that cellulose in the vermiculite-based composite material is incorporated between the aluminosilicate layers, forming a new crystalline phase. The nontronite-based composite material reduces the wear of friction pairs by a factor of 2.5 to 7.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Performance Specification for Standardized Transportation, Aging, and Disposal Canister Systems (Rev.2)

This performance specification document addresses use of a standardized transportation, aging, and disposal (STAD) canister system in the spent nuclear fuel (SNF) waste management system. This document was developed to support STAD canister system studies and potential research, development, and demonstration activities. Requirements in this specification may evolve with time based on results from analyses, experiments, design studies, system evaluations and demonstrations, as well as other factors. A STAD canister system consists of a canister, together with a storage or aging overpack/module/vault, a shielded transfer cask (STC), a site transporter, a transportation overpack, and a transportation skid. Three sizes of circular cross section STAD canister variants are specified in this document. The small STAD canister capacity is four pressurized water reactor (PWR) or nine boiling water reactor (BWR) SNF assemblies. The medium STAD canister capacity is 12 PWR or 32 BWR SNF assemblies. The large STAD canister capacity is 21 PWR or 44 BWR SNF assemblies. Using standardized canisters for SNF facilitates the interface between storage at an independent spent fuel storage installation (ISFSI) or a DOEowned interim storage facility (ISF), transportation between facilities, and disposal at a repository. Multiple STAD canisters may be stored in a single storage overpack and/or a single transportation overpack. The US Nuclear Regulatory Commission (NRC) requirements currently used for storage and transportation are adopted for the STAD canister system. Approved approaches (guidance) in NRC storage and transportation documents are also adopted as requirements for the STAD canister system to facilitate obtaining NRC Certificates of Compliance (CoCs) for STAD canister systems. Performance specifications in this document are also informed by STAD canister disposability in various geologic media and consideration of ISF (and geologic repository) handling facility design, operations, and licensing requirements.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Risk Inequality and the Food-Energy-Water (FEW) Nexus: A Study of 43 City Adaptation Plans

Goals aimed at adapting to climate change in sustainable and just ways are embedded in global agreements such as the Sustainable Development Goals and the New Urban Agenda. However, largely unexamined, are the ways that narrative understandings conveyed in adaptation plans consider and attempt to address inequality in climate risk to urban populations and FEW-systems. In this paper, we examine whether and how adaptation plans from C40 member cities address inequality in risk, by planning actions to reduce hazard exposure or tackling the drivers of social vulnerability. C40 is a network of 94 of the world's cities fostering policies to address climate change. We apply a mixed methods approach, including a discourse analysis and meta-analysis of adaptation plans. The discourse analysis helps to unpack framings of urban equity issues as they relate to policy actions, and the meta-analysis seeks to quantitatively investigate patterns of framing and policy across adaptation plans. Our findings suggest that FEW-nexus thinking is not yet embedded in narrative understandings of risk and planned adaptation actions, within the adaptation plans we studied. In the city adaptation plans we analyzed, we found multiple frames coexisting behind the broader adaptation visions (e.g., risk and resilience). Rather than converging, issues, and principles such as those of equality, coexist with economic issues in an imbalance of incongruent political movements and priorities. Techno-infrastructural and economic investments and concerns tend to take precedence over concerns and interests for inequality in climate risks. We discuss some of the institutional factors explaining this. Knowledge integration, for instance, is constrained by the existence of a plurality of sectors, levels of government, power, values, and ways of understanding and managing climate risk. We also suggest that the relatively low importance of equality considerations in the adaptation plans will likely limit the capacity of cities to support broader goals such as those of the New Urban Agenda and the Sustainable Development Goals.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗