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At least 487 records · Page 27

Chesapeake Bay Water Resources: Examining Turbidity and Sediment Dynamics in the Chesapeake Bay

An increase in total suspended sediment (TSS) concentrations and turbidity have contributed to poor water quality in the Chesapeake Bay since the 1970s. Although turbidity and TSS have been moderately improving over the past few decades, poor water quality is detrimental to the Chesapeake Bay’s ecosystems and the surrounding watersheds. The Summer 2022 Chesapeake Bay Water Resources project observed sediment dynamics and turbidity in the York River watershed using remote sensing tools, models, and Earth observations including NASA and United States Geological Survey’s (USGS) Landsat satellite series, NASA DEVELOP’s Optical Reef Coastal Area Assessment Tool 2.0 (ORCAA), and Soil and Water Assessment Tool (SWAT). The collaborators on this project were the Chesapeake Bay National Estuarine Research Reserve (CBNERR), Group on Earth Observations (GEO) AquaWatch, the Committee on Earth Observation Satellites Coastal Observations, Applications, Services and Tools (CEOS COAST), and the Virginia Department of Environmental Quality (VA DEQ). The team concluded that the upstream sections of the York River watershed increased in TSS from 2009–2019. However, the seasonal TSS patterns often correlated with higher precipitation levels, although not necessarily major storm events. This may be due to factors like wind and waves contributing to the sedimentation trends observed. Although projects have been conducted to improve water quality, additional efforts like planting riparian buffers along areas with high TSS are needed to reduce the intensity of runoff. The team’s results will allow the end user, the VA DEQ, to inform their policymaking regarding future Bay conservation efforts.

Katherine Hahn↗

Chesapeake Bay Water Resources: Characterization of Sediment Dynamics for Enhanced Water Quality Monitoring in the Chesapeake Bay

An increase in total suspended sediment (TSS) concentrations and turbidity have contributed to poor water quality in the Chesapeake Bay since the 1970s. Although turbidity and TSS have been moderately improving over the past few decades, poor water quality is detrimental to the Chesapeake Bay’s ecosystems and the surrounding watersheds. The Summer 2022 Chesapeake Bay Water Resources project observed sediment dynamics and turbidity in the York River watershed using remote sensing tools, models, and Earth observations including NASA and United States Geological Survey’s (USGS) Landsat satellite series, NASA DEVELOP’s Optical Reef Coastal Area Assessment Tool 2.0 (ORCAA), and Soil and Water Assessment Tool (SWAT). The collaborators on this project were the Chesapeake Bay National Estuarine Research Reserve (CBNERR), Group on Earth Observations (GEO) AquaWatch, the Committee on Earth Observation Satellites Coastal Observations, Applications, Services and Tools (CEOS COAST), and the Virginia Department of Environmental Quality (VA DEQ). The team concluded that the upstream sections of the York River watershed increased in TSS from 2009–2019. However, the seasonal TSS patterns often correlated with higher precipitation levels, although not necessarily major storm events. This may be due to factors like wind and waves contributing to the sedimentation trends observed. Although projects have been conducted to improve water quality, additional efforts like planting riparian buffers along areas with high TSS are needed to reduce the intensity of runoff. The team’s results will allow the end user, the VA DEQ, to inform their policymaking regarding future Bay conservation efforts.

Katherine Hahn↗

Solar Radiation Monitoring of Bluefield State College: Bluefield, West Virginia (Data)

The Historically Black Colleges and Universities (HBCU) Solar Radiation Monitoring Network operated from July 1985 through December 1996. Funded by DOE, the six-station network provided 5-minute averaged measurements of direct normal, global, and diffuse horizontal solar irradiance. The data were processed at NREL to improve the assessment of the solar radiation resources in the southeastern United States. Historical HBCU data available online include quality assessed 5-min data, monthly reports, and plots. In January 1997 the HBCU sites became part of the CONFRRM solar monitoring network and data from the two remaining active stations, Bluefield State College and Elizabeth City State University, are collected by the NREL Measurement & Instrumentation Data Center (MIDC).

14 SOLAR ENERGY↗

Tools Assessing Performance (TAP) 2.0

Dmitry Duplyakin will be presenting on the latest research and results in the Tools Assessing Performance (TAP) 2.0 project. This presentation will include updates on the latest data the group has produced, integration of obstacle models in the computational pipeline for distributed wind siting, and the plans for the near-term analysis and validation efforts. The talk will acknowledge the work of collaborators from NREL and three other national labs - ANL, LANL, and PNNL - all contributing to this multi-year project.

distributed wind↗

An RTDS-Based Testbed for Investigating the Impacts of Transmission-Level Disturbances on Solar PV Operation

The increasing penetration of renewable energy resources such as solar and wind via power electronic inverters is challenging grid dynamics, as well as grid planning, operation, and protection. Recently, the North American Electric Reliability Corporation (NERC) has reported a series of similar events of the unintended loss of solar generation in Southern California over a large geographic area following the transmission-level disturbances. These events highlight the importance of understanding the characteristics of the transmission-side disturbances propagating into the distribution systems and their impacts on the operation of inverter-based resources. In this paper, a real-time electromagnetic simulation testbed is constructed for real-time electromagnetic simulations to generate realistic transmission-level disturbances and investigate their impacts on the solar PV operation under different fault types and locations, solar penetration levels, and loading levels. Through the simulation analysis and grid strength assessment, it is found that the grid strength at points of integration (POIs) of solar PVs significantly affects the transient stability of solar generators. Particularly, undesirable transient stability events are more likely to occur at the weak POIs following the transmission-level disturbances. Moreover, undesirable transient stability events become severer when the transmission-level disturbance is closer to the weak POIs or the disturbances become more serious. Additionally, the impact of the transmission-level disturbances on the solar PVs at the weak POIs exacerbate with the increasing solar penetration levels and loading levels. Thus, it is important to study and develop new technologies for grid planning, operation, and protection in weak grid conditions to address the emerging issues of integrating the high penetration of solar PVs and other IBRs.

14 SOLAR ENERGY↗

A review of tidal energy—Resource, feedbacks, and environmental interactions

The ocean contains a variety of renewable energy resources, little of which has been exploited. Here, we review both tidal range and tidal stream energy, with a focus on the resource, feedbacks, and environmental interactions. The review covers a wide range of timescales of relevance to tidal energy, from fortnightly (spring-neap) and semi-diurnal variability, down to array, and device-scale turbulence. When simulating the regional tidal energy resource, and to assess environmental impacts, it is necessary to account for feedbacks between the tidal array and the resource itself. We critically review various methods for simulating energy extraction, from insights gained through theoretical studies of “tidal fences” in idealized channels, to realistic three-dimensional model studies with complex geometry and arrays of turbines represented by momentum sinks and additional turbulence due to the presence of rotors and support structures. We discuss how variability can be reduced by developing multiple (aggregated) sites with a consideration of the enhanced phase diversity offered by exploiting less energetic tidal currents. This leads to future research questions that have not yet been explored in depth at first-generation tidal sites in relatively sheltered channels (e.g., the interaction of waves with currents). Such enhanced understanding of real sea conditions, including the effects of wind and waves, leads to our other identified primary future research direction—reduced uncertainties in turbulence predictions, including the development of realistic models that simulate the interaction between ambient turbulence and the turbulence resulting from multiple wakes, and changes to system-wide hydrodynamics, water quality, and sedimentation.

Environmental impacts↗

Final TCF Report for Earth Battery: Storing Energy with Compressed Air and Heated Brine in Porous Rock

Cost-effective reductions in greenhouse gas (GHG) emissions are best achieved when all low-carbon energy resources are fully utilized. This includes base-load power: nuclear energy (NE) and fossil energy (FE), integrated with CO 2 capture, use, and storage (CCUS), and variable renewable energy (VRE) (wind and solar); but, current CCUS options don’t justify CO 2 -capture costs and existing energy-storage approaches lack the capacity and storage duration needed to fully utilize all forms of low-carbon energy without curtailment. The Earth Battery is designed to meet these challenges by synergistically integrating conventional- and renewable-energy resources, allowing each to contribute more efficiently to the grid than if operated independently. The Earth Battery stores energy underground as pressure and heat, using compressed air and/or CO 2 , together with heated brine. These fluids are stored in either saline aquifers used for CO 2 or natural gas (NG) storage or in oil and gas reservoirs, making deployment possible over much of the U.S. We can provide enormous energy-storage capacity and duration. The main goal of this study was to assess the techno-economic feasibility of the versions of the Earth Battery that use compressed air energy storage (CAES). Current CAES systems use NG turbines and store air in salt caverns, which limits geographic deployment. Conventional CAES wastes much of the heat of air compression, comprising half of the compression energy. Our technology addresses these deficiencies by using permeable sedimentary rock to store air and the heat of compression as heated brine. When electricity is needed, air and hot brine are produced, with hot brine used to pre-heat air before it is fed into the expanders. Key factors affecting round-trip efficiency are (1) pressure loss in the air-storage reservoir, which depends on permeability (> 100 mD being needed for efficient operations) and (2) temperature loss in the hot-brine storage reservoir, which decreases with time as the storage formation heats up. The original scope of this project was to conduct a techno-economic assessment of diurnal storage with the CAES Earth Battery, including (1) Adiabatic CAES, which requires no fossil fuel and (2) NG/CAES, where one or more of the expansion stages are NG fueled. During its assessment, we found NG/CAES, generates excess heat of compression that can be put into long-term (seasonal) storage and be utilized in a combined-cycle fashion with the addition of steam turbines. This resulted in our developing a new Earth Battery technology, which we call the Thermal Earth Battery. We conducted energy-system analyses for the Thermal Earth Battery for various combinations of heat sources: (1) heat of FE combustion, (2) excess heat of compression from NG/CAES, and (3) solar thermal energy (STE). The other Earth Battery class we developed compresses CO 2 , rather than air; hence, it is called Compressed CO 2 Energy Storage (CCES). Finally, we developed an improved, more efficient, more versatile version of the Allam cycle, which uses pressurized CO 2 , and developed various options for integrating renewable energy and energy storage. Our improved Allam-cycle technology minimizes cooling-water consumption, while enabling reliable, dispatchable renewable energy. Although not anticipated in our original scope of work, our Topic 1 project evolved into a highly productive discovery process wherein we developed a portfolio of Earth Battery configuration options and use cases. Our ultimate objective was to evaluate those options and use cases and determine the most optimal first best use options for our Earth Battery technology. That process resulted in identifying seasonal energy storage as a niche where no other energy storage technology could compete with us. As a result, we have identified the Thermal Earth Battery, which uses conventional steam-turbine components, and our improved Allam-cycle integrated with renewable energy and energy storage as the most promising technologies to commercialize in our Topic 2 proposal. Finally, our scope included finding a commercialization team for a Topic 2 continuation of this project, which we have successfully completed.

25 ENERGY STORAGE↗

Earth Battery: Storing Energy with Compressed Air and Heated Brine in Porous Rock (Final Technical Report)

Cost-effective reductions in greenhouse gas (GHG) emissions are best achieved when all lowcarbon energy resources are fully utilized. This includes base-load power: nuclear energy (NE) and fossil energy (FE), integrated with CO 2 capture, use, and storage (CCUS), and variable renewable energy (VRE) (wind and solar); but, current CCUS options don’t justify CO 2 -capture costs and existing energy-storage approaches lack the capacity and storage duration needed to fully utilize all forms of low-carbon energy without curtailment. The Earth Battery is designed to meet these challenges by synergistically integrating conventional- and renewable-energy resources, allowing each to contribute more efficiently to the grid than if operated independently. The Earth Battery stores energy underground as pressure and heat, using compressed air and/or CO 2 , together with heated brine. These fluids are stored in either saline aquifers used for CO 2 or natural gas (NG) storage or in oil and gas reservoirs, making deployment possible over much of the U.S. We can provide enormous energy-storage capacity and duration. The main goal of this study was to assess the techno-economic feasibility of the versions of the Earth Battery that use compressed air energy storage (CAES). Current CAES systems use NG turbines and store air in salt caverns, which limits geographic deployment. Conventional CAES wastes much of the heat of air compression, comprising half of the compression energy. Our technology addresses these deficiencies by using permeable sedimentary rock to store air and the heat of compression as heated brine. When electricity is needed, air and hot brine are produced, with hot brine used to pre-heat air before it is fed into the expanders. Key factors affecting round-trip efficiency are (1) pressure loss in the air-storage reservoir, which depends on permeability (> 100 mD being needed for efficient operations) and (2) temperature loss in the hot-brine storage reservoir, which decreases with time as the storage formation heats up.

25 ENERGY STORAGE↗

Market Opportunities for Deployable Wind Systems for Defense and Disaster Response

This report is the first public deliverable from the Defense and Disaster Deployable Turbine project, funded through the distributed wind portfolio of the U.S. Department of Energy Wind Energy Technologies Office. The objective of the project is to explore the opportunity for deployable turbine technologies to meet the operational energy needs of the U.S. military and global disaster response efforts. This report provides a market assessment that was conducted over a year using public reports, presentations at topical conferences, and direct stakeholder engagement interviews with both military and industry representatives. It begins with the high- level operational energy strategy of the Department of Defense that provides the context for alternatives to diesel fuel to meet energy needs. The report then provides an estimate of the energy use of the military in missions where a deployable turbine could potentially serve as an alternative to the baseline use of diesel fuel in generators to provide electricity in remote locations. An overview of domestic and international disaster response is provided with a focus on the role of the military in providing energy to those events. Finally, the report summarizes the technical considerations that would enable a deployable turbine to meet military and disaster response energy needs including the global wind resource, the technical design of the turbine, and the operational constraints of various military missions.

17 WIND ENERGY↗

Catalyst design for small molecule activation of energy consequence

This project targets the conversion of ubiquitous small molecules (e.g. NO, CO, H 2 O) into viable precursors to synthetic fuels. Current state of the art catalyst design has not directly targeted transition metal complexes capable of mediating the multi-electron redox processes necessary to reduce the overpotential (energy loss) required achieve efficient activation of small molecule substrates. In this vein, a new strategy has been developed for the assembly of polynuclear architectures; allowing for the construction of tunable polymetallic centers that assemble easily within a pre-organized template (conferring stability, selectivity and tunability) that can effect multi-electron redox processes for reactions. Catalyst development has commenced with the following target design elements: (1) catalysts featuring multiple transition metal ions in the same reaction space to greatly expand accessible molecular redox capabilities; (2) catalysts are assembled in a polynucleating ligand framework that permits control over the cluster morphology as well as the local steric and electronic environment of the transition metal ions within the cluster. The high-tunability of the catalyst composition (metal content) and geometric flexibility has permitted a rigorous assessment of electronic-structure-to-function relationship to be developed, further guiding synthetic efforts to realize more potent catalysts. The numerous permutations possible showcase the high degree of generality to this approach with many synthetic handles to tune redox and reaction chemistry. Trinuclear complexes have been synthesized featuring homo- and hetero-trinuclear cores featuring a variety of first row transition metal ions (Cr→Ni). The molecular clusters have been shown to successfully mediate multi-electron redox processes in a cooperative fashion without requiring strong chemical reductants or oxidants. The reactive molecular complexes are being utilized to activate and breakdown the robust bonds within typical waste stream small molecules (e.g., greenhouse gases) and convert them into value-added commodity chemicals. Ultimately, the catalysts developed by this approach will be required to convert energy acquired via renewable resources (e.g., solar or wind) into synthetic fuels as an energy storage mechanism.

10 SYNTHETIC FUELS↗

Simulation of the 2003 Foss Barge - Point Wells Oil Spill: A Comparison between BLOSOM and GNOME Oil Spill Models

The Department of Energy’s (DOE’s) National Energy Technology Laboratory’s (NETL’s) Blowout and Spill Occurrence Model (BLOSOM), and the National Oceanic and Atmospheric Administration’s (NOAA’s) General NOAA Operational Modeling Environment (GNOME) are compared. Increasingly complex simulations are used to assess similarities and differences between the two models’ components. The simulations presented here are forced by ocean currents from a Finite Volume Community Ocean Model (FVCOM) implementation that has excellent skill in representing tidal motion, and with observed wind data that compensates for a coarse vertical ocean model resolution. The comprehensive comparison between GNOME and BLOSOM presented here, should aid modelers in interpreting their results. Beyond many similarities, aspects where both models are distinct are highlighted. Some suggestions for improvement are included, e.g., the inclusion of temporal interpolation of the forcing fields (BLOSOM) or the inclusion of a deflection angle option when parameterizing wind-driven processes (GNOME). Overall, GNOME and BLOSOM perform similarly, and are found to be complementary oil spill models. This paper also sheds light on what drove the historical Point Wells spill, and serves the additional purpose of being a learning resource for those interested in oil spill modeling. The increasingly complex approach used for the comparison is also used, in parallel, to illustrate the approach an oil spill modeler would typically follow when trying to hindcast or forecast an oil spill, including detailed technical information on basic aspects, like choosing a computational time step. We discuss our successful hindcast of the 2003 Point Wells oil spill that, to our knowledge, had remained unexplained. The oil spill models’ solutions are compared to the historical Point Wells’ oil trajectory, in time and space, as determined from overflight information. Our hindcast broadly replicates the correct locations at the correct times, using accurate tide and wind forcing. While the choice of wind coefficient we use is unconventional, a simplified analytic model supported by observations, suggests that it is justified under this study’s circumstances. We highlight some of the key oceanographic findings as they may relate to other oil spills, and to the regional oceanography of the Salish Sea, including recommendations for future studies.

42 ENGINEERING↗

Role of Alternative Energy Sources: Hydropower Technology Assessment

This report discusses the role of hydropower in meeting the energy needs of the United States (U.S.). This includes an analysis of key issues related to hydropower and, where applicable, the modeling of the environmental and cost aspects of hydropower. Conventional hydropower is a significant source of electricity in the U.S. In 2009, conventional hydropower in the United States produced 253 terawatt-hours of electricity, equivalent to 72 percent of total renewable power generation or 6.9 percent of the total power generation in the United States during that year. The capacity of installed hydropower has remained relatively flat since 2000 (near 77 GW). The resource base for very large hydropower sites in the U.S. has already been developed. However, many smaller conventional hydropower sites, such as those with capacities up to 400 MW, are still available along with upgrades to existing facilities. Newer technologies for generating hydropower are emerging. For example, hydrokinetic systems harness the energy that is contained in water as it moves past a fixed point by employing in stream turbines that typically resemble small scale horizontal axis wind turbines. New hydrokinetic turbines are currently being installed along the Mississippi River system.

13 HYDRO ENERGY↗

Phase I Microgrid Cost Study: Data Collection and Analysis of Microgrid Costs in the United States

The U.S. Department of Energy (DOE) Office of Electricity Microgrid Cost Study project is looking at identifying the costs of components, integration and installation of U.S. microgrids and project cost improvements and technical accelerators over the next 5 years and beyond. This information could then be used by the DOE among others, to develop R&D agendas for the development of the next generation microgrids that provide cost effective, reliable and clean energy solutions. Microgrids are gaining in popularity because of their adaptability and flexible expandability, the need for increased electricity reliability, the increased affordability of distributed energy resources (DERs) and grid intelligence devices, goals to reduce greenhouse gas emissions, and other factors. The U.S. Department of Energy commissioned the National Renewable Energy Laboratory to complete a microgrid cost study and develop a microgrid cost model. The goal is to elucidate the variables that have the highest impact on costs as well as potential areas for cost reduction. This study consists of two phases. Phase I comprises the collection and analysis of data from microgrid projects built in the United States and is the subject of this report. In Phase II, NREL will assess current barriers facing the industry and identify potential solutions with help from industry representatives. Microgrid components are classified as follows in the form used to collect cost data from industry representatives for NREL's microgrid cost database: DERs: diesel, natural gas, combined heat and power (CHP), biofuel, solar photovoltaic (PV), wind, and fuel cell and energy storage; microgrid controller: primary, secondary, or tertiary; additional infrastructure: distribution system infrastructure, information technology communications upgrades, metering, etc.; soft costs: engineering, construction, commissioning, and regulatory. The purposes of Phase I are to better determine the contribution of individual components to total project size and to identify cost differences in projects within the same market segment. Phase II will use the results of Phase I to have an initial indication of the costs that might be driving the cost of development the most.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Characterization of Turbulent Latent and Sensible Heat Flux Exchange Between the Atmosphere and Ocean in MERRA

Turbulent fluxes of heat and moisture across the atmosphere-ocean interface are fundamental components of the Earth's energy and water balance. Characterizing both the spatiotemporal variability and the fidelity of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-ocean feedbacks, and improving model predictability. This study examines the veracity of the recently completed NASA Modern-Era Retrospective analysis for Research and Applications (MERRA) product with respect to its representation of the surface turbulent heat fluxes. A validation of MERRA turbulent heat fluxes and near-surface bulk variables at local, high-resolution space and time scales is achieved by making comparisons to a large suite of direct observations. Both in situ and satellite-observed gridded surface heat flux estimates are employed to investigate the spatial and temporal variability of the surface fluxes with respect to their annual mean climatologies, their seasonal covariability of near-surface bulk parameters, and their representation of extremes. The impact of data assimilation on the near-surface parameters is assessed through evaluation of incremental analysis update tendencies produced by the assimilation procedure. It is found that MERRA turbulent surface heat fluxes are relatively accurate for typical conditions but have systematically weak vertical gradients in moisture and temperature and have a weaker covariability between the near-surface gradients and wind speed than found in observations. This results in an underestimate of the surface latent and sensible heat fluxes over the western boundary current and storm track regions. The assimilation of observations mostly acts to bring MERRA closer to observational products by increasing moisture and temperature near the surface and decreasing the near-surface wind speeds. The major patterns of spatial and temporal variability of the turbulent heat fluxes produced by MERRA compare favorably to observationally based estimates. However, MERRA is distinct in terms of amplitude. These results suggest that MERRA is likely to be a valuable resource for a number of research applications though, as with all turbulent flux estimates, systematic issues should be taken into account

Robert, J. Brent↗

Characterization of Turbulent Latent and Sensible Heat Flux Exchange Between the Atmosphere and Ocean in MERRA

Turbulent fluxes of heat and moisture across the atmosphere-ocean interface are fundamental components of the Earth s energy and water balance. Characterizing both the spatiotemporal variability and the fidelity of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-ocean feedbacks, and improving model predictability. This study examines the veracity of the recently completed NASA Modern-Era Retrospective analysis for Research and Applications (MERRA) product with respect to its representation of the surface turbulent heat fluxes. A validation of MERRA turbulent heat fluxes and near-surface bulk variables at local, high-resolution space and time scales is achieved by making comparisons to a large suite of direct observations. Both in situ and satellite-observed gridded surface heat flux estimates are employed to investigate the spatial and temporal variability of the surface fluxes with respect to their annual mean climatologies, their seasonal covariability of near-surface bulk parameters, and their representation of extremes. The impact of data assimilation on the near-surface parameters is assessed through evaluation of incremental analysis update tendencies produced by the assimilation procedure. It is found that MERRA turbulent surface heat fluxes are relatively accurate for typical conditions but have systematically weak vertical gradients in moisture and temperature and have a weaker covariability between the near-surface gradients and wind speed than found in observations. This results in an underestimate of the surface latent and sensible heat fluxes over the western boundary current and storm track regions. The assimilation of observations mostly acts to bring MERRA closer to observational products by increasing moisture and temperature near the surface and decreasing the near-surface wind speeds. The major patterns of spatial and temporal variability of the turbulent heat fluxes produced by MERRA compare favorably to observationally based estimates. However, MERRA is distinct in terms of amplitude. These results suggest that MERRA is likely to be a valuable resource for a number of research applications though, as with all turbulent flux estimates, systematic issues should be taken into account.

Roberts, J. Brent↗

An Assessment of Land Availability and Price in the Coterminous United States for Conversion to Algal Biofuel Production

Realistic economic assessment of land-intensive alternative energy sources (e.g., solar, wind, and biofuels) requires information on land availability and price. Accordingly, we created a comprehensive, national-scale model of these parameters for the United States. For algae-based biofuel, a minimum of 1.04E+05 km2 of land is needed to meet the 2022 EISA target of 2.1E+10 gallons year-1. We locate and quantify land types best converted. A data-driven model calculates the incentive to sell and a fair compensation value (real estate and lost future income). 1.02E+6 km2 of low slope, non-protected land is relatively available including croplands, pasture/ grazing, and forests. Within this total there is 2.64E+5 km2 of shrub and barren land available. The Federal government has 7.68E+4 km2 available for lease. Targeting unproductive lands minimizes land costs and impacts to existing industries. However, shrub and barren lands are limited by resources (water) and logistics, so land conversion requires careful consideration.

agriculture↗

Aerothermodynamics at NASA-Langley Research Center

The Aerothermodynamics Branch at NASA - Langley Research Center is tasked with developing, assessing and applying aerothermodynamic technologies to enable the development of hypersonic aircraft, launch vehicles, and planetary/earth entry systems. To accomplish this mission, the Branch capitalizes on the synergism between the experimental and computational facilities/tools which reside in the branch and a staff that can draw on five decades of experience in aerothermodynamics. The Aerothermodynamics Branch is staffed by 30 scientists/engineers. The staff, of which two-thirds are less than 40 years old, is split evenly between experimentalists and computationalists. Approximately 90 percent of the staff work on space transportation systems while the remainder work on planetary missions. The Branch manages 5 hypersonic wind tunnels which are staffed by 14 technicians, numerous high end work stations and a SGI Origin 2000 system. The Branch also utilizes other test facilities located at Langley as well as other national and international test sites. Large scale computational requirements are met by access to Agency resources.

Weilmuenster, K. James↗

Estimating Renewable Energy Economic Potential in the United States. Methodology and Initial Results

This report describes a geospatial analysis method to estimate the economic potential of several renewable resources available for electricity generation in the United States. Economic potential, one measure of renewable generation potential, may be defined in several ways. For example, one definition might be expected revenues (based on local market prices) minus generation costs, considered over the expected lifetime of the generation asset. Another definition might be generation costs relative to a benchmark (e.g., a natural gas combined cycle plant) using assumptions of fuel prices, capital cost, and plant efficiency. Economic potential in this report is defined as the subset of the available resource technical potential where the cost required to generate the electricity (which determines the minimum revenue requirements for development of the resource) is below the revenue available in terms of displaced energy and displaced capacity. The assessment is conducted at a high geospatial resolution (more than 150,000 technology-specific sites in the continental United States) to capture the significant variation in local resource, costs, and revenue potential. This metric can be a useful screening factor for understanding the economic viability of renewable generation technologies at a specific location. In contrast to many common estimates of renewable energy potential, economic potential does not consider market dynamics, customer demand, or most policy drivers that may incent renewable energy generation.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗