Investigation of a rare event where the polar ionospheric reverse convection potential does not saturate during a period of extreme northward IMF solar wind driving
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C. Robert Clauer↗
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Results for “wind potential”
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Inter-Area Oscillation Damping with Type-5 Wind Power Plant: Preprint
This paper investigates the potential of using brushless excitation (BLE) for not only riding through the fault but also to damp inter-area power oscillation with the help of a synchronous generator (SG) used in Type 5 Wind Power Plant (WPP). In BLE, an auxiliary synchronous generator (ASG) behaving like an exciter is coupled and driven by the rotor of the main SG. The BLE's field current's ASG is fed by two separate loops of the automatic voltage regulator (AVR) and Power System Stabilizer (PSS). The AVR system implements a control loop to regulate the generator terminal voltage, VT. For the PSS, the kinetic energy of the wind turbine is utilized according to the estimated rotational speed of the synchronous generator shaft of the SG. It mitigates the necessity of any curtailment of active power for damping. The effectiveness of the proposed control scheme is verified with a three-phase short circuit fault in a two-area power system.
brushless↗
Observations of winds with an incoherent lidar detector
A Fabry-Perot interferometer and image-plane detector system to be used as a receiver for a Doppler lidar have been developed. This system incorporates the latest technology in multichannel detectors, and it is an important step toward the development of operational wind profiler systems for the atmosphere. The instrumentation includes a stable high-resolution optically contacted plane etalon and a multiring anode detector to scan the image plane of the Fabry-Perot interferometer spatially. The high wavelength resolution provided by the interferometer permits the aerosol and molecular components of the backscattered signal to be distinguished, and the Doppler shift of either component can then be used to determine the wind altitude profile. The receiver performance has been tested by measuring the wind profile in the boundary layer. The Fabry-Perot interferometer and image-plane detector characteristics are described and sample measurements are presented. The potential of the system as a wind profiler in the troposphere, the stratosphere, and the mesosphere is also considered.
Abreu, Vincent J.↗
Design and Analysis of a Tool for Automated Fiber Placement of Composite Wind Tunnel Blades
For decades, composite wind tunnel blades have been constructed using labor-intensive hand layup processes. Automated Fiber Placement (AFP) is a relatively new technology that has not seen widespread use in manufacturing composite wind tunnel blades. AFP offers the potential for reduced manufacturing time, reduced cost, and improved consistency compared to traditional hand layup procedures. These manufacturing qualities are becoming increasingly important as existing wind tunnel blades are replaced due to impact damage or wear and tear from decades of use. Researchers at the NASA Langley Research Center are currently using the Integrated Structural Assembly of Advanced Composites (ISAAC) facility to investigate the feasibility of AFP for manufacturing composite wind tunnel blades. ISAAC uses manufacturing tools as surfaces on which to place fiber tows. A manufacturing tool was developed for using AFP to build a wind tunnel blade shape. This paper presents the structural design and analysis of this tool, for use with AFP, constructed from high temperature thermoplastics. The tool fabricated by this design process was successfully used for AFP and oven cure of two representative airfoil shaped composite structures.
Brian Mason↗
Elemental and charge state composition of the fast solar wind observed with SMS instruments on WIND
The elemental composition and charge state distributions of heavy ions of the solar wind provide essential information about: (1) atom-ion separation processes in the solar atmosphere leading to the 'FIP effect' (the overabundance of low First Ionization potential (FIP) elements in the solar wind compared to the photosphere); and (2) coronal temperature profiles, as well as mechanisms which heat the corona and accelerate the solar wind. This information is required for solar wind acceleration models. The SWICS instrument on Ulysses measures for all solar wind flow conditions the relative abundance of about 8 elements and 20 charge states of the solar wind. Furthermore, the Ulysses high-latitude orbit provides an unprecedented look at the solar wind from the polar coronal holes near solar minimum conditions. The MASS instrument on the WIND spacecraft is a high-mass resolution solar wind ion mass spectrometer that will provide routinely not only the abundances and charge state of all elements easily measured with SWICS, but also of N, Mg, S. The MASS sensor was fully operational at the end of 1994 and has sampled the in-ecliptic solar wind composition in both the slow and the corotating fast streams. This unique combination of SWICS on Ulysses and MASS on WIND allows us to view for the first time the solar wind from two regions of the large coronal hole. Observations with SWICS in the coronal hole wind: (1) indicate that the FIP effect is small; and (2) allow us determine the altitude of the maximum in the electron temperature profile, and indicate a maximum temperature of approximately 1.5 MK. New results from the SMS instruments on Wind will be compared with results from SWICS on Ulysses.
Gloeckler, G.↗
21-Year Modeled Spatiotemporal Low-Level Jet Climatology Along the U.S. Mid-Atlantic Coast
Offshore wind farms are influenced by a variety of meteorological phenomena, ranging in spatial and temporal extent. One of these phenomena, the low-level jet (LLJ), is defined as a local maximum in wind speed with height in the planetary boundary layer, exhibiting a "nose-like" structure usually in the lowest few hundred meters above the surface. This vertical extent of LLJs may coincide with the rotor-swept area of a wind turbine, thus having implications for potential power production and mechanical loading. Previous studies in this area based on observations have confirmed the prevalence of LLJs here, with implications on power generation, wind turbine loads, and wake recovery depending on the LLJ characteristics, such as nose height and what part of the wind turbine power curve is being impacted.
LLJ↗
Expected occurrence of wildlife in US Atlantic offshore wind areas
Offshore wind energy has entered a pivotal phase of development for the U.S. Atlantic Outer Continental Shelf (OCS), a region that supports critical habitats, migratory corridors and flyways for many marine species. Assessing where and when marine wildlife occurs is a crucial first step in developing a risk assessment framework to evaluate potential risks and impacts of offshore wind development. In this study, we perform this initial assessment by evaluating the expected occurrence of marine mammal, seabird and sea turtle taxa in areas of interest to identify patterns and potential areas of concern. Specifically, this work depicts the expected monthly density of 84 marine species and taxa within each of the 29 active wind energy lease areas plus a 10 km buffer to account for nearby activity. We then compare these densities to subregional thresholds, evaluated as the 90th percentile of the subregion’s monthly density, to provide comparisons across the shelf region. This analysis synthesizes the most recent spatial distribution models of 31 marine mammal taxa (26 species and 5 guilds), 49 seabird species and 4 sea turtle species to provide a unified evaluation of the major marine wildlife in the region. Out of the 84 species and taxa analyzed, 56 exhibit levels of expected density in wind energy areas that exceed the corresponding 90th percentile subregional threshold at some point throughout the year. These results represent an initial assessment in the broader Occurrence, Exposure, Response, and Consequence (OERC) framework, originally developed by the U.S. Navy for marine species risk assessments. These results offer valuable guidance to marine spatial planners, management agencies and offshore wind developers on the expected locations and timing of interaction risk to wildlife species in or near wind energy areas across the region.
17 WIND ENERGY↗
On the role of sea surface temperature gradients in forcing low-level winds and convergence in the tropics
The potential contribution of the SST gradient-driven flow to the low-level (p not less than 700 mb) convergence over tropical oceans is determined using a simple one-layer model of the trade cumulus boundary layer wherein surface temperature gradients are mixed vertically (consistent with the ECMWF analyzed data). The influence of the layers above 700 mb is intentionally suppressed. The results of the study demonstrate the importance of taking account of the fact that cumulonimbus convection takes a small but finite time to adjust to low-level convergence. Failure to consider this effect leads to unreasonably large equatorial convergence.
Lindzen, Richard S.↗
Windblown sand on Mars: The effect of saltation threshold on drift potentials derived from Mars GCM
The rate at which the wind can redistribute sedimentary material is an important part of any planet's sedimentologic cycle, particularly for Mars, where the competing effects of other gradational processes are less than on Earth. The aeolian drift potential (DP) is a measure of the amount of material capable of being moved through a unit length by the wind for a given period of time. DP is a useful measure of the potential redistribution rate of windblown material on regional scales. The Martian aeolian DP was calculated from laboratory studies of sand movement conducted at Martian atmospheric densities and from surface stress, temperature, and pressure values for that region as determined from the Mars General (Atmospheric) Circulation Model (GCM) developed at the NASA/Ames Research Center. In our simulations for Mars, DP changes in both magnitude (as expected) and direction if the saltation threshold is altered.
Xu, P.↗
Assessment of Offshore Wind Energy Leasing Areas for Humboldt and Morro Bay Wind Energy Areas, California
The National Renewable Energy Laboratory (NREL) is providing scientific and technical services to the Bureau of Ocean Energy Management (BOEM) under an interagency agreement. The purpose of this report is to provide technical assistance in delineating potential lease areas from the California wind energy areas (WEAs) that can be competitively auctioned to wind energy developers. Each wind energy area is presumed to be technically and economically feasible for wind energy development based on the economic cost study performed by NREL in 2020. The subsequent analysis summarized in this report is intended to help BOEM maximize efficient offshore wind energy resource use and ensure fair return to the Government for use of the lease areas, by making recommendations for viable ways to divide the WEAs into auctionable commercial lease areas of approximately equal value. We considered several factors that affect the value of lease areas for wind energy development, including mean wind speeds, water depth, seafloor gradient, seismicity, hard substrate, and access to infrastructure. The largest impact to generating capacity came from the choice of mooring technology and the resulting setback from the lease area boundaries. Based on our setback assumptions, the generating capacity for a wind plant using catenary moorings could be nearly 30% less than with vertical moorings in Humboldt, or approximately 20% less in Morro Bay. The likely range of generating capacity is 1.5 to 3 GW in Humboldt and 3 to 5 GW in Morro Bay.
17 WIND ENERGY↗
Observing system simulation experiments related to space-borne Lidar wind profiling. Part 2: Sensitivity to atmospheric and instrumental influences
Three major potential sources of errors that influence the performance of the proposed LIDAR wind profiling systems are accounted for in the following simulation studies. First, the coherent CO2 laser system proposed by NOAA/ERL for the WINDSAT requires distributions of 10 microns size aerosol concentrations throughout the atmosphere to determine the Doppler shifted backscatter signal. Second, atmospheric influences such as clouds and precipitation affect the LIDAR system's ability to obtain complete vertical wind profiles. In this study, experiments are reported on in which the complete wind profiles are only available in model generated cloud-free regions down to model cloud tops. Third, constraints on the available power required for the expected operational lifetime duration of a LIDAR system govern the number of pulses which can be used to sample a 300 km square area.
Dlouhy, R.↗
Preparations for Tomographic Background-Oriented Schlieren at the 31-Inch Mach 10 Wind Tunnel
This paper details effort by researchers at NASA Langley Research Center to prepare for an upcoming high-speed tomographic background-oriented schlieren test entry in the 31-Inch Mach 10 wind tunnel. In order to troubleshoot potential problems that will arise when setting up the experiment in the actual test facility, a full-scale mock-up of the 31-Inch Mach 10 wind tunnel test section was constructed in the laboratory to provide equivalent characteristic optical access and mounting options. A 3D-printed model that replicates the scale of the forebody of a supersonic retropropulsion (SRP) model that will be used in the final test entry has been fabricated with a central nozzle that can be connected to a high-pressure gas supply to approximate the nozzle flow that will occur. Six high-speed imaging systems consisting of a high-speed camera with a fiber illuminator module have been assembled and mounted on the test section mock-up to provide six unique perspective views of the nozzle flow from the model. Tests with one of the imaging systems using a pulsed laser light source showed that sufficient signal intensity and illumination uniformity was achieved, as demonstrated by the 2D BOS data obtained with the system. Additional work to show that retroreflective material would survive inside of the test section of the 31-Inch Mach 10 tunnel was also performed. Finally, a remotely-controlled tomographic BOS calibration system is discussed.
Brett F Bathel↗
Wind Energy Accomplishments and Year-End Performance Report: Fiscal Year 2022
Four decades ago, construction was just beginning on experimental turbines at the National Wind Technology Center (NWTC). Today, the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) facility is the centerpiece of the laboratory's Flatirons Campus, a world-class hub for renewable energy research. The nation's shift to 100% clean electricity by 2035 will require a mix of renewable energy sources and strategies - and together, wind and solar energy could account for 60% to 80% of that clean energy resource. In Fiscal Year (FY) 2022, NREL scientists, engineers, and analysts contributed to these visionary goals through their wind energy research. As wind innovations push into new areas, NREL continues to play a vital role in advancing technology and addressing deployment barriers in pursuit of more efficient, reliable, and predictable wind energy systems. FY 2022 wind research and development explored the potential for dramatic growth in land-based systems, the launch of the nation's first commercial-scale offshore installations, and transmission infrastructure buildout. Land-based wind energy is one of the most cost-effective electricity supply options - but utility-scale deployment will require up to 10 times the current number of turbines. An NREL plan addressed this need to accelerate U.S. wind technology rollout at distributed and utility scales. Another project conducted by NREL and the Pacific Northwest National Laboratory (PNNL) helps position the nation's first major offshore wind corridor for success. The WETO-funded Atlantic Offshore Wind Transmission Study is evaluating options for balancing electricity supply and demand, while supporting resilience of the grid and marine industries. WETO, NREL, and other partners are working to enable the enormous supply chain and workforce changes the U.S. wind energy industry will need to meet net-zero-carbon-emissions targets. As part of a seminal series of DOE-funded supply chain studies, NREL analysts reported on the trade-offs involved in manufacturing large volumes of wind technologies, while addressing cost, workforce, and logistics issues. All of this research is supported by NREL's outstanding research teams, tools, data, and facilities. A WETO-funded international wind energy field campaign, the American WAKE experimeNt (AWAKEN), has brought together experts from NREL, PNNL, and Sandia National Laboratories to create the world's most comprehensive set of high-resolution data on wind energy atmospheric phenomenon. This study could lead to more accurate predictions of losses from turbine-to-turbine wake interactions, eventually helping wind plants capture more energy and operators save millions of dollars. In addition, NREL researchers developed testing, modeling, and analysis tools to improve the security of power grids by identifying wind power plant dynamic stability problems. A new Stochastic Soaring Raptor Simulator (SSRS) protects golden eagles from turbine encounters by predicting flight paths. This report provides more detail on these top achievements and other accomplishments made by NREL and its partners during FY 2022 (between October 1, 2021, and September 30, 2022).
accomplishments↗
Aeolian Processes at the Mars Exploration Rover Opportunity Landing Site
The traverse of the Mars Exploration Rover Opportunity across its Meridiani Planum landing site has shown that wind has affected regolith by creating drifts, dunes, and ubiquitous ripples, by sorting grains during aeolian transport, by forming bright wind streaks downwind from craters seen from orbit, and by eroding rock with abrading, wind-blown material. Pre-landing orbiter observations showed bright and dark streaks tapering away from craters on the Meridiani plains. Further analysis of orbiter images shows that major dust storms can cause bright streak orientations in the area to alternate between NW and SE, implying bright wind streak materials encountered by Opportunity are transient, potentially mobilized deposits. Opportunity performed the first in situ investigation of a martian wind streak, focusing on a bright patch of material just outside the rim of Eagle crater. Data from Pancam, the Miniature Thermal Emission Spectrometer (Mini-TES), the Alpha-Particle X-Ray Spectrometer (APXS), and the Mossbauer spectrometer either are consistent with or permit an air fall dust interpretation. We conclude that air fall dust, deposited in the partial wind shadow of Eagle crater, is responsible for the bright streak seen from orbit, consistent with models involving patchy, discontinuous deposits of air fall dust distributed behind obstacles during periods of atmospheric thermal stability during major dust storms.
Sullivan, R.↗
A robust offering strategy for wind producers considering uncertainties of demand response and wind power
This paper proposes a risk-constrained decision-making approach for a wind power producer participating in the day-ahead market. In the developed model, a flexible demand response trading scheme between the wind power producer and different customers is employed. Through the proposed demand response mechanism, the wind power producer is able to trade demand response resource internally with different customers, and then trade energy externally with the market to increase the expected profit and the wind energy utilization. The uncertainties in the wind power and demand response are modeled by using the information gap decision theory approach from risk averse (robust) and risk-seeking (opportunistic) perspectives. The objective of the robust model is to maximize the robust level while satisfying the desired profit, whereas the opportunistic model aims to evaluate the possibility of achieving windfall profits with favorable uncertainties. The overall offering strategy problem is modeled as a bi-objective mixed integer nonlinear programming, which is linearized by proper techniques and solved efficiently by using the normal boundary intersection technique. In this work, simulation results show that utilizing demand response resource to mitigate wind power deviations can increase a wind power producer's profit and reduce potential risks. In addition, the results demonstrate that the proposed bi-objective optimization approach enables the wind power producer to select appropriate offering decisions with respect to uncertainties.
17 WIND ENERGY↗
Observations During GRIP from HIRAD: Images of C-Band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate
HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be inferred. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. To the extent possible, comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eyewall, location of vortex wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.
Miller, Timothy L.↗
Observations of C-band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate from the Hurricane Imaging Radiometer (HIRAD)
HIRAD flew on the WB-57 over Earl and Karl during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new Cband radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. (The resulting swath width for a platform at 60,000 feet is roughly 60 km, and resolution for most of the swath is around 2 km.) By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be retrieved. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years to obtain observations within a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. Comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eyewall, location of storm wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.
Miller, Timothy L.↗
New Observations of C-band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate From the Hurricane Imaging Radiometer (HIRAD)
HIRAD flew on the WB-57 during NASA's GRIP (Genesis and Rapid Intensification Processes) campaign in August September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be retrieved. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years to obtain observations within a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. Comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eyewall, location of storm wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.
Miller, Timothy L.↗