The State-Of-The-Art in Short-Term Prediction of Wind Power. A
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Weather and Climate: Changing Human Exposures K
CHAPTER 2 Weather and climate: changing human exposures K. L. Ebi,1 L. O. Mearns,2 B. Nyenzi3 Introduction Research on the potential health effects of weather, climate variability and climate change requires understanding of the exposure of interest. Although often the terms weather and climate are used interchangeably, they actually represent different parts of the same spectrum. Weather is the complex and continuously changing condition of the atmosphere usually considered on a time-scale from minutes to weeks. The atmospheric variables that characterize weather include temperature, precipitation, humidity, pressure, and wind speed and direction. Climate is the average state of the atmosphere, and the associated characteristics of the underlying land or water, in a particular region over a par- ticular time-scale, usually considered over multiple years. Climate variability is the variation around the average climate, including seasonal variations as well as large-scale variations in atmospheric and ocean circulation such as the El Niño/Southern Oscillation (ENSO) or the North Atlantic Oscillation (NAO). Climate change operates over decades or longer time-scales. Research on the health impacts of climate variability and change aims to increase understanding of the potential risks and to identify effective adaptation options. Understanding the potential health consequences of climate change requires the development of empirical knowledge in three areas (1): 1. historical analogue studies to estimate, for specified populations, the risks of climate-sensitive diseases (including understanding the mechanism of effect) and to forecast the potential health effects of comparable exposures either in different geographical regions or in the future; 2. studies seeking early evidence of changes, in either health risk indicators or health status, occurring in response to actual climate change; 3. -
Environmental Systems the Atmosphere and Hydrosphere
Environmental Systems The atmosphere and hydrosphere THE ATMOSPHERE The atmosphere, the gaseous layer that surrounds the earth, formed over four billion years ago. During the evolution of the solid earth, volcanic eruptions released gases into the developing atmosphere. Assuming the outgassing was similar to that of modern volcanoes, the gases released included: water vapor (H2O), carbon monoxide (CO), carbon dioxide (CO2), hydrochloric acid (HCl), methane (CH4), ammonia (NH3), nitrogen (N2) and sulfur gases. The atmosphere was reducing because there was no free oxygen. Most of the hydrogen and helium that outgassed would have eventually escaped into outer space due to the inability of the earth's gravity to hold on to their small masses. There may have also been significant contributions of volatiles from the massive meteoritic bombardments known to have occurred early in the earth's history. Water vapor in the atmosphere condensed and rained down, of radiant energy in the atmosphere. The sun's radiation spans the eventually forming lakes and oceans. The oceans provided homes infrared, visible and ultraviolet light regions, while the earth's for the earliest organisms which were probably similar to radiation is mostly infrared. cyanobacteria. Oxygen was released into the atmosphere by these early organisms, and carbon became sequestered in sedimentary The vertical temperature profile of the atmosphere is variable and rocks. This led to our current oxidizing atmosphere, which is mostly depends upon the types of radiation that affect each atmospheric comprised of nitrogen (roughly 71 percent) and oxygen (roughly 28 layer. This, in turn, depends upon the chemical composition of that percent). -
Wind Energy Forecasting: a Collaboration of the National Center for Atmospheric Research (NCAR) and Xcel Energy
Wind Energy Forecasting: A Collaboration of the National Center for Atmospheric Research (NCAR) and Xcel Energy Keith Parks Xcel Energy Denver, Colorado Yih-Huei Wan National Renewable Energy Laboratory Golden, Colorado Gerry Wiener and Yubao Liu University Corporation for Atmospheric Research (UCAR) Boulder, Colorado NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. S ubcontract Report NREL/SR-5500-52233 October 2011 Contract No. DE-AC36-08GO28308 Wind Energy Forecasting: A Collaboration of the National Center for Atmospheric Research (NCAR) and Xcel Energy Keith Parks Xcel Energy Denver, Colorado Yih-Huei Wan National Renewable Energy Laboratory Golden, Colorado Gerry Wiener and Yubao Liu University Corporation for Atmospheric Research (UCAR) Boulder, Colorado NREL Technical Monitor: Erik Ela Prepared under Subcontract No. AFW-0-99427-01 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. National Renewable Energy Laboratory Subcontract Report 1617 Cole Boulevard NREL/SR-5500-52233 Golden, Colorado 80401 October 2011 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 This publication received minimal editorial review at NREL. NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. -
Wind Characteristics 1 Meteorology of Wind
Chapter 2—Wind Characteristics 2–1 WIND CHARACTERISTICS The wind blows to the south and goes round to the north:, round and round goes the wind, and on its circuits the wind returns. Ecclesiastes 1:6 The earth’s atmosphere can be modeled as a gigantic heat engine. It extracts energy from one reservoir (the sun) and delivers heat to another reservoir at a lower temperature (space). In the process, work is done on the gases in the atmosphere and upon the earth-atmosphere boundary. There will be regions where the air pressure is temporarily higher or lower than average. This difference in air pressure causes atmospheric gases or wind to flow from the region of higher pressure to that of lower pressure. These regions are typically hundreds of kilometers in diameter. Solar radiation, evaporation of water, cloud cover, and surface roughness all play important roles in determining the conditions of the atmosphere. The study of the interactions between these effects is a complex subject called meteorology, which is covered by many excellent textbooks.[4, 8, 20] Therefore only a brief introduction to that part of meteorology concerning the flow of wind will be given in this text. 1 METEOROLOGY OF WIND The basic driving force of air movement is a difference in air pressure between two regions. This air pressure is described by several physical laws. One of these is Boyle’s law, which states that the product of pressure and volume of a gas at a constant temperature must be a constant, or p1V1 = p2V2 (1) Another law is Charles’ law, which states that, for constant pressure, the volume of a gas varies directly with absolute temperature. -
Characterisation of Intra-Hourly Wind Power Ramps at the Wind Farm Scale and Associated Processes
Wind Energ. Sci., 6, 131–147, 2021 https://doi.org/10.5194/wes-6-131-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Characterisation of intra-hourly wind power ramps at the wind farm scale and associated processes Mathieu Pichault1, Claire Vincent2, Grant Skidmore1, and Jason Monty1 1Department of Mechanical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia 2School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia Correspondence: Mathieu Pichault ([email protected]) Received: 12 May 2020 – Discussion started: 5 June 2020 Revised: 15 September 2020 – Accepted: 8 December 2020 – Published: 19 January 2021 Abstract. One of the main factors contributing to wind power forecast inaccuracies is the occurrence of large changes in wind power output over a short amount of time, also called “ramp events”. In this paper, we assess the behaviour and causality of 1183 ramp events at a large wind farm site located in Victoria (southeast Australia). We address the relative importance of primary engineering and meteorological processes inducing ramps through an automatic ramp categorisation scheme. Ramp features such as ramp amplitude, shape, diurnal cycle and seasonality are further discussed, and several case studies are presented. It is shown that ramps at the study site are mostly associated with frontal activity (46 %) and that wind power fluctuations tend to plateau before and after the ramps. The research further demonstrates the wide range of temporal scales and behaviours inherent to intra-hourly wind power ramps at the wind farm scale. 1 Introduction hourly) ramp forecasts (Zhang et al., 2017; Cui et al., 2015; Gallego et al., 2015a). -
EFDA-JET Bulletin
EFDA-JET Bulletin JET Recent Results and Planning March 2006 On 23rd January 2006, the EFDA Associate Leader for JET Dr Jérôme Paméla presented the JET 2005 report and future programme in a seminar at the JET site. In his talk, Dr Paméla outlined the most recent news regarding fusion, the 2005 JET main events and scientific highlights, the 2006 JET programme, and planning beyond 2006. "2005 was a key year for fusion with the decision on siting ITER in Cadarache taken by the parties on 28 June 2005. India joined in November and ITER negotiations were completed in December 2005. The negotiation with Japan led to other projects being jointly prepared between the European Union and Japan, the so-called ‘Broader Approach’, a very good opportunity for faster development of fusion," stressed Dr Paméla. Some of the scientific results obtained at JET in 2005, which were outlined in the talk, are presented in this Bulletin. The current European fusion research strategy, reflected in the longer-term planning for JET, was also described in detail. In the upcoming campaigns significant enhancement of the JET facility, towards higher power with the ITER-like plasma shape will allow JET to perform important experiments in preparation of ITER. At the end of this year, an ITER-like ICRH Antenna is to be installed which will open new scope for reactor-relevant research at JET. These experiments shall be followed by the installation of an ITER-like first wall scheduled for 2008 (see the June 2005 JET Bulletin). JET in the Physics World The March issue of the Institue of Physics magazine, Physics World, carries an 8 page special feature on JET. -
5 Minute Wind Forecasting Challenge: Exelon and GE's Predix
The 5 Minute Wind Forecasting Challenge: Exelon and GE’s Predix At a Glance A move toward digital industrial transformation As a leading utility company with more than $31 billion in global Renewable Energy revenues in 2016 and over 32 gigawatts (GW) of total generation, Exelon knows the importance of taking a strategic view of digital transformation across its lines of business. Challenge Exelon sought to optimize wind power forecasting by predicting wind Exelon was developing strategies for managing its various generation ramp events, enabling the company to dispatch power that could not be assets across nuclear, fossil fuels, wind, hydro, and solar power as well monetized otherwise. The result is higher revenue for Exelon’s large-scale wind farm operations. as determining how it would leverage the enormous amount of data those assets would generate going forward. Solution GE and Exelon teams co-innovated to build a solution on Predix that In evaluating its strategies, the company reviewed its current increases wind forecasting accuracy by designing a new physical and statistical wind power forecast model that uses turbine data on-premises OT/IT infrastructure across its entire energy portfolio. together with weather forecasting data. This model now represents Business leaders looked at the system administration challenges the industry-leading forecasting solution (as measured by a substantial and costs they would face to maintain the current infrastructure, let reduction in under-forecasting). alone use it as a basis for driving new revenue across its business Results units. This assessment made digital transformation an even greater Exelon’s wind forecasting prediction accuracy grew signifcantly, enabling imperative, and inspired discussions about how Exelon could leverage higher energy capture valued at $2 million per year. -
Weather & Climate
Weather & Climate July 2018 “Weather is what you get; Climate is what you expect.” Weather consists of the short-term (minutes to days) variations in the atmosphere. Weather is expressed in terms of temperature, humidity, precipitation, cloudiness, visibility and wind. Climate is the slowly varying aspect of the atmosphere-hydrosphere-land surface system. It is typically characterized in terms of averages of specific states of the atmosphere, ocean, and land, including variables such as temperature (land, ocean, and atmosphere), salinity (oceans), soil moisture (land), wind speed and direction (atmosphere), and current strength and direction (oceans). Example of Weather vs. Climate The actual observed temperatures on any given day are considered weather, whereas long-term averages based on observed temperatures are considered climate. For example, climate averages provide estimates of the maximum and minimum temperatures typical of a given location primarily based on analysis of historical data. Consider the evolution of daily average temperature near Washington DC (40N, 77.5W). The black line is the climatological average for the period 1979-1995. The actual daily temperatures (weather) for 1 January to 31 December 2009 are superposed, with red indicating warmer-than-average and blue indicating cooler-than-average conditions. Departures from the average are generally largest during winter and smallest during summer at this location. Weather Forecasts and Climate Predictions / Projections Weather forecasts are assessments of the future state of the atmosphere with respect to conditions such as precipitation, clouds, temperature, humidity and winds. Climate predictions are usually expressed in probabilistic terms (e.g. probability of warmer or wetter than average conditions) for periods such as weeks, months or seasons. -
NAWEA 2015 Symposium Book of Abstracts
NAWEA 2015 Symposium Tuesday 09 June 2015 - Thursday 11 June 2015 Virginia Tech Campus Goodwin Hall Book of Abstracts i Table of contents Wind Farm Layout Optimization Considering Turbine Selection and Hub Height Variation ....................... 1 Graduate Education Programs in Wind Energy ................................................................................. 2 Benefits of vertically-staggered wind turbines from theoretical analysis and Large-Eddy Simulations ........... 3 On the Effects of Directional Bin Size when Simulating Large Offshore Wind Farms with CFD ................... 7 A game-theoretic framework to investigate the conditions for cooperation between energy storage operators and wind power producers ............................................................................................................ 9 Detection of Wake Impingement in Support of Wind Plant Control ....................................................... 11 Sensitivity of Wind Turbine Airfoil Sections to Geometry Variations Inherent in Modular Blades ................ 15 Exploiting the Characteristics of Kevlar-Wall Wind Tunnels for Conventional Aerodynamic Measurements with Implications for Testing of Wind Turbine Sections ...................................................................... 16 Spatially Resolved Wind Tunnel Wake Measurements at High Angles of Attack and High Reynolds Numbers Using a Laser-Based Velocimeter .................................................................................................... 17 Windtelligence: -
Whither the Weather Analysis and Forecasting Process?
520 WEATHER AND FORECASTING VOLUME 18 FORECASTER'S FORUM Whither the Weather Analysis and Forecasting Process? LANCE F. B OSART Department of Earth and Atmospheric Sciences, The University at Albany, State University of New York, Albany, New York 5 December 2002 and 19 December 2002 ABSTRACT An argument is made that if human forecasters are to continue to maintain a skill advantage over steadily improving model and guidance forecasts, then ways have to be found to prevent the deterioration of forecaster skills through disuse. The argument is extended to suggest that the absence of real-time, high quality mesoscale surface analyses is a signi®cant roadblock to forecaster ability to detect, track, diagnose, and predict important mesoscale circulation features associated with a rich variety of weather of interest to the general public. 1. Introduction h day-1 QPF scores made by selected NCEP models, By any objective or subjective measure, weather fore- including the Nested Grid Model (NGM; Hoke et al. casting skill has improved signi®cantly over the last 40 1989), the Eta Model (Black 1994), and the Aviation years. By way of illustration, Fig. 1 shows the annual Model [AVN, now called the Global Forecast System threat score for 24-h quantitative precipitation forecast (GFS); Kanamitsu et al. (1991); Kalnay et al. (1998)]. (QPF) amounts of 1.00 in. (2.5 cm) or more over the The key point to be made from Fig. 2 is that HPC contiguous United States for 1961±2001 as produced by forecasters have been able to sustain approximately a forecasters at the Hydrometeorological Prediction Cen- 0.05 threat score advantage over the NCEP numerical ter (HPC) of the National Centers for Environmental models during this 12-yr period (and longer, not shown) Prediction (NCEP). -
Carbon Disclosure Project 2011
CDP 2011 Investor CDP 2011 Information Request Carbon Disclosure Project Centrica Module: Introduction Page: Introduction 0.1 Introduction Please give a general description and introduction to your organization About Centrica Our vision is to be the leading integrated energy company in our chosen markets. We source, generate, process, store, trade, save and supply energy and provide a range of related services. We secure and supply gas and electricity for millions of homes and business and offer a range of home energy solutions and low carbon products and services. We have strong brands and distinctive skills which we use to achieve success in our chosen markets of the UK and North America, and for the benefit of our employees, our customers and our shareholders. In the UK, we source, generate, process and trade gas and electricity through our Centrica Energy business division. We store gas through Centrica Storage and we supply products and services to customers through our retail brand British Gas. In North America, Centrica operates under the name Direct Energy, which now accounts for about a quarter of group turnover. We believe that climate change is one of the single biggest global challenges. Energy generation and energy use are significant contributors to man-made greenhouse gas (GHG) emissions, a driver of climate change. As an integrated energy company, we play a pivotal role in helping to tackle climate change by changing how energy is generated and how consumers use energy. Our corporate responsibility (CR) vision is to be the most trusted energy company leading the move to a low carbon future. -
National Grid ESO Technical Report on the Events of 9 August 2019
Technical Report on the events of 9 August 2019 6 September 2019 2 Contents Executive Summary .................................................................................... 4 1. Introduction ................................................................................................. 7 2. Roles ........................................................................................................... 8 2.1. ESO Roles and Responsibilities ........................................................................................... 8 2.2. Transmission System Owner Roles and Responsibilities ..................................................... 9 2.3. Generator Roles and Responsibilities ................................................................................... 9 2.4. DNO Roles and Responsibilities ........................................................................................... 9 3. Description of the Event ............................................................................ 10 3.1. System Conditions Prior to the Event ................................................................................. 10 3.2. Summary of the Event ......................................................................................................... 10 3.3. Detailed Timeline ................................................................................................................ 13 3.4. Impact on Frequency .......................................................................................................... 15