Characterizing meteorological forecast impact on microgrid optimization performance and design

A microgrid consists of electrical generation sources, energy storage assets, loads, and the ability to function independently, or connect and share power with other electrical grids. Thefocus of this work is on the behavior of a microgrid, with both diesel generator and photovoltaic resources, whose heating or cooling loads are influenced by local meteorological conditions. Themicrogrid\u27s fuel consumption and energy storage requirement were then examined as a function of the atmospheric conditions used by its energy management strategy (EMS). A fuel-optimal EMS, able to exploit meteorological forecasts, was developed and evaluated using a hybrid microgrid simulation. Weather forecast update periods ranged from 15 min to 24 h. Four representative meteorological sky classifications (clear, partly cloudy, overcast, or monsoon) were considered. Forall four sky classifications, fuel consumption and energy storage requirements increased linearly with the increasing weather forecast interval. Larger forecast intervals lead to degraded weather forecasts, requiring more frequent charging/discharging of the energy storage, increasing both the fuel consumption and energy storage design requirements. The significant contributions of this work include the optimal EMS and an approach for quantifying the meteorological forecast effects on fuel consumption and energy storage requirements on microgrid performance. The findings of this study indicate that the forecast interval used by the EMS affected both fuel consumption and energy storage requirements, and that the sensitivity of these effects depended on the 24-hour sky conditions

Optical turbulence and rawinsonde measurements for 17-28 September 1989 at Anderson Mesa/United States Naval Observatory, Flagstaff, Arizona

The Naval Postgraduate School Atmospheric Optics Group acquired atmospheric optical turbulence and navaid radiosonde (rawinsonde) data in the Flagstaff, Arizona region part of a site survey for a large-scale, ground-based, synthetic aperture system (100-300 m baseline stellar interferometer). From 17 to 25 September 1989, measurements were taken from the Lowell Observatory 31- inch telescope dome facility on Anderson Mesa, 16 km southeast of Flagstaff. Further sampling occurred 26-28 September 1989 from the United States Naval Observatory's (USNO) 61-inch telescope dome, approximately 8 km west of Flagstaff. The parameters measured consisted of transverse coherence lengths, isoplanatic angles, and various meteorological surface and upper-air variables measured from a high resolution, instrumented balloon (rawinsonde) system. This report compiles, analyses and summarizes the acquired data. A summary of the synoptic scale activities occurring simultaneously over the data acquisition sites is also presentedhttp://archive.org/details/opticalturbulenc00vaucN

Correlation of atmospheric optical turbulence and meteorological measurements

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This report presents data gathered by the Naval Postgraduate School (NPS) during the South Central Coast Aerometric Monitoring Project (SCCCAMP) in September and October of 1985. The data are from a triaxial monostatic doppler acoustic sounder and a 20-meter meteorological tower which were located at the Ellwood pier near Goleta, California and from rawinsondes launched from the R/V Acania in the Santa Barbara Channel. Keywords include: Boundary layer, Doppler Acoustic Sounder, and Rawinsondehttp://archive.org/details/sodarrawinsondes00shawN

Atmospheric optical turbulence measurements taken at Anderson Mesa, Flagstaff, Arizona between 13-19 November 1989

From 13 to 19 November 1989, the Naval Postgraduate School Atmospheric Optics Group acquired atmospheric optical turbulence measurements at the 31-inch Lowell Observatory telescope dome facility on Anderson Mesa, 16 km southeast of Flagstaff, Arizona. The parameters measured, the transverse coherence length and the isoplanatic angle, were part of an ongoing site survey for a large-scale, ground-based, synthetic aperture system (100-300 m baseline stellar interferometer). This report compiles, analyses and summarizes the acquired optical data. Also discussed are the synoptic meteorological events present during the data acquisition period.Prepared for: Naval Research Laboratory, Washington D.C.; WL/ARCA Kirtland Air Force Base, New Mexicohttp://archive.org/details/atmosphericoptic00vaucMIPR# WLK-0-143NAApproved for public release; distribution is unlimited

Shipboard observations of mean and turbulent atmospheric surface layer quantities SCCCAMP data report, Part I

3 Weeks of aerometric observations from a shipboard platform are described and analyzed to obtain surface layer quantities relevant to the dispersion of pollutants from offshore oil operations. Momentum, heat, and moisture flux were estimated with two different methods: the dissipation technique and bulk parameterizations. Diffusion scale turbulence was measured with bivane anemometers and estimates of ship motion contributions to these measurements were performed. Keywords: Turbulence diffusion; Measurements; and Santa Barbara Channel. (Author)http://archive.org/details/shipboardobserva00skupN

Atmospheric optical turbulence measurements taken at Anderson Mesa, Flagstaff, Arizona between 10-19 July 1990

From 10 to 19 July 1990, the Naval Postgraduate School Atmospheric Optics Group acquired atmospheric optical turbulence measurements at the 13-inch Lowell Observatory astrographic telescope dome on Anderson Mesa, 16 km southeast of Flagstaff, Arizona. This collection of transverse coherence lengths and isoplanatic angles was the last in a three part Anderson Mesa site-survey measurement set for a large-scale, ground-based, synthetic aperture system (100- 300 m baseline stellar interferometer). The intent of this report is to compile, analyze and summarize the acquired optical data, as well as correlate the meteorological and optical conditions present during the data acquisitionsPrepared for: the Naval Research Laboratory, Washington D.C. and WL/ARCA, Kirtland Air Force Base, New Mexicohttp://archive.org/details/atmosphericoptic91007vaucNaval Research Lab, WL/ARCA(Air Force)NAApproved for public release; distribution is unlimited

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Microgrid Energy Management during High-Stress Operation

We consider the energy management of an isolated microgrid powered by photovoltaics (PV) and fuel-based generation with limited energy storage. The grid may need to shed load or energy when operating in stressed conditions, such as when nighttime electrical loads occur or if there is little energy storage capacity. An energy management system (EMS) can prevent load and energy shedding during stress conditions while minimizing fuel consumption. This is important when the loads are high priority and fuel is in short supply, such as in disaster relief and military applications. One example is a low-power, provisional microgrid deployed temporarily to service communication loads immediately after an earthquake. Due to changing circumstances, the power grid may be required to service additional loads for which its storage and generation were not originally designed. An EMS that uses forecasted load and generation has the potential to extend the operation, enhancing the relief objectives. Our focus was to explore how using forecasted loads and PV generation impacts energy management strategy performance. A microgrid EMS was developed exploiting PV and load forecasts to meet electrical loads, harvest all available PV, manage storage and minimize fuel consumption. It used a Model Predictive Control (MPC) approach with the instantaneous grid storage state as feedback to compensate for forecasting errors. Four scenarios were simulated, spanning a stressed and unstressed grid operation. The MPC approach was compared to a rule-based EMS that did not use load and PV forecasting. Both algorithms updated the generator’s power setpoint every 15 min, where the grid’s storage was used as a slack asset. While both methods had similar performance under unstressed conditions, the MPC EMS showed gains in storage management and load shedding when the microgrid was stressed. When the initial storage was low, the rule-based EMS could not meet the load requirements and shed 16% of the day’s electrical load. In contrast, the forecast-based EMS managed the load requirements for this scenario without shedding load or energy. The EMS sensitivity to forecast error was also examined by introducing load and PV generation uncertainty. The MPC strategy successfully corrected the errors through storage management. Since weather affects both PV energy generation and many types of electrical loads, this work suggests that weather forecasting advances can improve remote microgrid performance in terms of fuel consumption, load satisfaction, and energy storage requirements

Skinfold Thickness in North American Infants 24-41 Weeks Gestation

Weight, length, head circumference, skinfold thickness (triceps, biceps, subscapular, abdominal), and arm circumference were obtained within 72 hours of birth from 642 singleton, Caucasian infants born at 24-41 weeks gestation in Tucson, Arizona. Birthweights for term and preterm infants were similar to those reported for a comparable sea level population.From 24 to 41 weeks gestation skinfold thickness (SFT) increased at all sites from an average of 1.0 mm to 3.4 mm; arm circumference doubled; mid-arm cross- sectional fat area increased from 12 to 18 percent of the total cross-sectional mid­arm area; and the ratio of arm circumference/head circumference rose from 0.23 to 0.31. SFT measurements at the four sites were highly intercorrelated and without evidence of lateralization at birth. The rate of fat deposition, as assessed by change in median SFT, rose rapidly after 32 weeks gestation, peaking at 38-39 weeks and declining thereafter. These data may be helpful in determining nutritional status at birth and assessing postnatal growth of term and preterm North American infants