North American Wind Energy Academy 2015 Symposium

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The NAWEA 2015 Symposium, which was held June 9-11, 2015 at Virginia Tech in Blacksburg, VA, included technical sessions, panel discussions, a graduate student symposium, a poster session, engineering software workshops, a business meeting, social events, and a tour of the Virginia Tech Stability Tunnel. The Symposium, the second in a series of technical meetings, examined a broad range of topics required to achieve high wind penetration in the North American power-generation sector. In addition to wind energy system science and technology technical tracks, the symposium featured sessions that provided holistic perspectives, overviews, and approaches necessary to maximize future deployment including:

  • Research and Development, and Technology, including presentations on Aerodynamics, Aeroacoustics, Controls, Innovative Systems and Concepts, Reliability, Offshore, etc.
  • Electrical Integration, including presentations on issues of achieving high penetration of variable renewables and on energy storage issues
  • Atmosphere/Turbine/Wake Interactions, including farm/plant interactions and array effects
  • Atmospheric Science of Wind Characterization, and Forecasting
  • Public Policy Issues, including presentations, and a panel discussion of issues/problems and how technology can provide solutions, economics of wind
  • Environmental and Siting Issues, including presentations, and a panel discussion of issues/problems and how technology can provide solutions
  • Workforce Development and Education, including presentations, and a panel discussion from the Education Committee
-, retrieved 2015-05-13


Recent Submissions

Now showing 1 - 20 of 82
  • Wind Energy: Retrospective, Prospective and the Role of Universities
    Manwell, James F. (Virginia Tech, 2015-06-10)
  • An Experimental Investigation on Surface Water Transport and Ice Accreting Process Pertinent to Wind Turbine Icing Phenomena
    Hu, Hui (Virginia Tech, 2015-06)
    Wind turbine icing represents the most significant threat to the integrity of wind turbines in cold weather. Ice accretion on turbine blades would decrease power production of the wind turbines significantly. Ice accretion and irregular shedding during wind turbine operation would lead to load imbalances as well as excessive turbine vibration, often causing the wind turbine to shut off. Icing issues can also directly impact personnel safety due to falling and projected large ice chunks. It should be noted that the icing hazard is often most severe in the locations which are best suited for wind turbine sites, such as northern latitudes, off-shore wind farms and high altitudes (i.e. mountains). Wind turbines in these regions are more prone to water contamination and icing in cold weather. Advancing the technology for safe and efficient wind turbine operation in atmospheric icing conditions requires the development of innovative, effective anti-/de-icing strategies tailored for wind turbine icing mitigation and protection. Doing so requires a keen understanding of the underlying physics of complicated thermal flow phenomena pertinent to wind turbine icing phenomena, both for the icing itself as well as for the water runback along contaminated surfaces of wind turbine blades. In the present study, a series of experimental investigations were conducted to characterize the transient behavior of wind-driven water film/rivulet flows over a NACA 0012 airfoil model and the dynamic ice accreting process over the airfoil model in order to elucidate the underlying physics of the important microphysical processes pertinent to wind turbine icing phenomena. The experimental study was conducted in an icing research tunnel available at Aerospace Engineering Department of Iowa State University. A suite of advanced flow diagnostic techniques, such as molecular tagging velocimetry and thermometry (MTV), digital image projection (DIP), and infrared (IR) imaging thermometry techniques, were developed and applied to achieve quantitative measurements of the film thickness distributions of the surface water film/rivulet flows and the temperature distributions of the water/ice mixture flows over the airfoil model surface at different test conditions. The new findings derived from the present icing physics study would lead to a better understanding of the important micro-physical processes, which could be used to improve current icing accretion models for more accurate prediction of ice formation and ice accretion on wind turbine blades as well as development of effective anti-/de-icing strategies tailored for safer and more efficient operation of wind turbines in cold weather.
  • Welcome to the North American Wind Energy Academy Symposium 2015
    Thresher, Bob (Virginia Tech, 2015-06-09)
  • Academic Qualification in Onshore and Offshore Wind Energy within the Framework of the European Academy of Wind Energy and the European Wind Energy Master Program - Examples and Experiences in Germany and Europe
    Kaern, Moses (Virginia Tech, 2015-06-10)
    The development of research and education in wind energy in Europe varies greatly between the member states. Building on these national achievements the European Academy of Wind Energy (EAWE) is integrating and connecting the activities of the highest level academic and research institutes in Europe. Leading universities in The Netherlands, Denmark, Germany, and Norway have joined forces to form the elite European Wind Energy Master (EWEM) building on different local programs at the partner universities: Delft University of Technology, Technical University of Denmark, Carl von Ossietzky University Oldenburg, Norwegian University of Science and Technology. While academic education on master and PhD levels is strongly based on international cooperation and consortia, the barriers in professional and continuing education to cooperate internationally are higher. The presentation will explain the concepts of the European Wind Energy Master and the continuing study programs Wind Energy Technology and Management and Offshore Wind Energy. Possibilities for cooperation will be discussed.
  • Current Status of DOE Wind Resource Characterization Efforts
    Cline, Joel (Virginia Tech, 2015-06-11)
    The Department of Energy is leading a second Wind Forecast Improvement Project (WFIP2), which will aim to improve modeling of complex flow. The National Oceanic and Atmospheric Administration (NOAA) will collaborate with DOE and its national labs, and the team led by Vaisala, which includes academic, utility and renewable energy partners. WFIP2 aims to improve model physics and bridge models that describe multiple scales in complex flow. Observations collected during a 12-18 month field campaign in an area bounded by the Columbia River Gorge and Vansycle Ridge will be used for model verification and assimilation. Scales of physical phenomena of interest range from meso-beta (20-200 km) through the meso-gamma (2-20 km) to the microscale (< 1 km). Physical phenomena of particular interest include frontal passages, gap flows, convective outflows, mountain waves, topographic wakes, and marine pushes. The instrumentation for the field campaign, which will begin in the summer of 2015, includes radar wind profilers, sodars, lidar wind profilers, scanning Doppler lidars, microwave radiometers, sonic anemometers, ceilometers, range gauges, high resolution microbarographs, surface energy budget sensors. Sensors on tall towers and wind turbines will also be used. NOAA's 13-km Rapid Refresh (RAP; spanning North America) and 3-km High-Resolution Rapid Refresh (HRRR; covering the CONUS) will be the primary forecast models for this study. The RAP and HRRR are hourly updating assimilation and model forecast system, capable of assimilating many types of observations, including near-surface and aircraft in-situ observations as well as radar reflectivity and satellite radiances. The RAP produces 18-h forecasts and the HRRR produces 15-h forecasts every hour, both using the Advanced Research version of the Weather Research and Forecast (WRF-ARW) model as the forecast model component. The HRRR uses the RAP for lateral boundary conditions. Within the HRRR, a concurrent 750-m nest will be used to develop scale-aware physical parameterization during WFIP2. Model improvements at all scales will be made available to the public via the WRF-ARW repository. NOAA will assimilate special WFIP2 observations, using them to verify the operational RAP and HRRR forecasts. Selected cases that are poorly forecast and deemed important to wind power production will be re-simulated with modifications to key physical parameterizations (boundary layer, surface layer, etc.) in an attempt to reduce forecast errors. The most significant model improvements as well as the collective model improvements will further be tested in retrospective experiments involving the full RAP and HRRR domains in order to ensure robust improvements for general weather prediction as well as the complex flows of focus in this project. Retrospective runs will also be run by NOAA's hourly-updated North American Mesoscale Rapid Refresh (NAMRR) system, which includes the full 12-km North American domain and the 3-km CONUS nest domain.
  • European Academy of Wind Energy and the European Wind Energy Master Program – Study Programs at the University of Oldenburg and in Europe
    Kaern, Moses (Virginia Tech, 2015-06-10)
    Many different approaches for academic qualification in wind energy have been developing in Europe. The European Academy of Wind Energy (EAWE) provides a framework for the exchange of ideas, scientists, and the development of strategies. The efforts to join forces in university education started more than ten years ago and resulted in the establishment of the European Wind Energy Master. EAWE started already in 2004 as a network of universities engaged in wind energy research and PhD education. Today, EAWE's 39 members -- universities and research institutions -- formulate and execute joint R&D projects and coordinate high quality scientific research and education in wind energy. One of the core activities has always been the exchange of scientists, PhD and graduate students, as well as the annual EAWE PhD seminar. EAWE is now responsible for the Scientific Track of European Wind Energy association's Annual Events and organizes the much appreciated biannual conference series "The Science of Making Torque from Wind". Four EAWE members have joined forces to push international education through a joint master program, the European Wind Energy Master (EWEM). The program was established in 2012 by four universities who have long been active in Wind Energy and Offshore Wind Energy research and education: Delft University of Technology, Technical University of Denmark, Carl von Ossietzky University Oldenburg, Norwegian University of Science and Technology. The master program is supported by the European Union through its Erasmus Mundus excellence program. The European Wind Energy Master is an advanced 2 year program dedicated to specialized research within four areas: Wind Physics, Rotor Design, Electric Power Systems, and Offshore Engineering. Students have to choose one of those four tracks and follow that dedicated curriculum. EWEM graduates receive a double degree by the two (of the four) universities who are responsible for the scientific track. Already three cohorts of students have been taken in, and the number of students is stable. EWEM is supported by a network of 43 associated partners from all over the world: research institutions, universities, and companies. Putting together a joint master program like EWEM would not have been possible without each partner's longstanding experience in research and education. In fact, EWEM strongly depends on the existence of local programs and degrees being able to contribute to such an extensive wind energy program. While the development at the four partner universities has been different because of the different national university policies, wind energy market developments, and research funding schemes, some general issues can be highlighted when looking at the case of the University of Oldenburg. Already in the early 1980s' University of Oldenburg started research on renewable energies at the Physics Department. The researchers at the Energy Lab were ahead of their time at the forefront of sustainable energy technology research: they studied different renewable energy sources and their integration into one system. First, university education has only been done as specialization within a classical degree, i.e. Physics, but it was extended through the establishment of one of the first master programs for renewables: the Postgraduate Program for Renewable Energy (PPRE) which now, after 27 years of operation, is supported by a network of 400 alumni in over 80 countries. Apart from that, research and education in wind energy has developed further into a highly specialized field at the University of Oldenburg within the Institute of Physics focussing on the physical aspects of wind as a resource for energy conversion – and branding this field as “Wind Physics”. The institutionalization of wind energy research has eventually been brought forward a major step in the year 2004 when ForWind, the Center for Wind Energy Research, has been founded. Today, ForWind and its three partners, the Universities of Oldenburg, Hannover, and Bremen, have gained national and international reputation, making them an interesting partner for a Strategic Research Alliance with the German Aerospace Center (DLR) and the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) in 2012. So, becoming part of the EWEM consortium in 2012 is an outcome of successful research, networking, and institutional growth over more than two decades -- and that is true also for the three other partners. In 2006 ForWind has stretched its educational activities to continuing study programs and part-time education for professionals in wind and offshore wind. The Continuing Studies Program Wind Energy Technology is one year part-time study program covering all aspects related to the planning, development, and operation of onshore wind farms. It addresses professionals from all disciplines -- technical, commercial, legal -- and provides them with a systematic understanding of wind farm projects. Participants should hold a master degree and have at least three years of professional experience. Much emphasis is based on the exchange among the participants of the courses and the exchange of their expertise. Lecturers of the course are known experts in the field, and they come from companies and universities. The graduates gain important competencies to succeed in the highly interdisciplinary wind industry and business. There is a variant to this course devoted explicitly to offshore wind, the Continuing Studies Program Offshore Wind Energy. Due to the nature of offshore wind farm projects the offshore course is taught in English, and the program has just recently established co-operations with a leading UK institution and a company in Denmark. In the last 9 years more than 220 professionals have graduated and form a vital alumni network with regular meetings at trade fairs and other business events.
  • Wind Industry Market and Policy Overview
    Hunt, Hannah (Virginia Tech, 2015-06)
  • Sustainable Energy: Institute for Critical Technology and Applied Science (ICTAS)
    Priya, Shashank; Grove, Dennis (Virginia Tech, 2015-06)
  • The Impact of Offshore Wind Turbines on Underwater Ambient Noise Levels
    Glegg, Stewart (Virginia Tech, 2015-06)
    The underwater sound levels generated by offshore wind turbine farms is a concern because of the possible environmental impact on marine mammals. This paper will consider how sound generated by a wind turbine is transmitted into a shallow water channel. It is shown that the underwater sound levels can be calculated for a typical offshore wind turbine by using the theory of Chapman and Ward (1990) combined with aeroacoustic models of trailing edge noise on the wind turbine blades. A procedure is given for estimating the underwater sound levels from a wind turbine whose airborne noise levels are known. The results indicate that the sound levels are strongly modulated at the blade passing frequency, which leads to infrasound that is more easily detected than a continuous sound source of the same level.
  • Flare Reduction Technique for Near-Surface Airfoil Boundary Layer Measurements with Laser Diagnostics
    Shin, Dongyun; Cadel, Daniel R.; Lowe, K. Todd (Virginia Tech, 2015-06)
  • Wind Farm Layout Optimization Considering Commercial Turbine Selection and Hub Height Variation
    Abdulrahman, Mamdouh; Wood, David H. (Virginia Tech, 2015-06)
    New aspects is added to the wind farm layout optimization problem. A variable hub height non-identical turbines wind farm design is presented. The manufacturers' technical data for 61 commercial horizontal axis wind turbine models is used in order to obtain more realistic results. Three objective functions are considered individually: (1) the total power production, (2) the farm capacity factor, and (3) the capital cost of output power index (based on nominal power and tower height). The results show that the flexibility of using non-identical turbines with different heights in the same wind farm can meet a wide range of preferences. By adapting the objective functions' weighting factors many preferred solutions can be obtained. Summary : The results show that the flexibility of using non-identical turbines with different heights in the same wind farm can meet a wide range of preferences. By adapting the objective functions' weighting factors many preferred solutions can be obtained. The enhancement of such flexible design on both TPP and CCI becomes more significant in limited land (small valued of S) and/or low wind class cases. This makes the presented design suitable for compact designs as well as the relatively low exergy sites.
  • Integrating Real-World Case Studies into Wind Energy Graduate Education
    Swift, Andrew H. P., Jr.; Pattison, Chris (Virginia Tech, 2015-06)
    Wind power continues to grow rapidly as a fuel source for the electric power industry in the US. Recent data for 2014 show that wind power in Texas alone delivered in excess of 10 percent of the annual electrical energy consumed in the state. With this growth has emerged the need for a professionally educated national workforce to support the industry and sustain future growth. With the original support of the Texas Workforce Commission in 2008, both undergraduate and graduate wind energy education programs have been established at Texas Tech University. A series of multidisciplinary courses have been developed by the six full-time faculty to support the degree and certificate programs. Total wind energy student course enrollments over approximately 20 wind energy courses offered each semester are averaging 400 to 500. The offerings are both face to face (in-class) and by distance delivery. Starting in Fall 2014 TTU partnered with DNV GL to offer real-world case studies as part of the graduate course offerings. Four case studies were offered in each of two graduate classes - Advanced Technical Wind Energy I and Advanced Managerial Wind Energy I. The case studies covered technical, environmental, and site management topics for a single turbine project, a multi-turbine power plant, an offshore installation, and wind turbine technology innovations. The case studies were delivered remotely allowing students to benefit from real-life examples and the interaction with members of the wind industry. This presentation will discuss an outline of the cases, best practices for integrating industry participation to maximize student benefit, and effective delivery methods - what worked well and what can be improved.
  • A game-theoretic framework to investigate the conditions for cooperation between energy storage operators and wind power producers
    Bhela, Siddharth; Tam, Kwa-sur (Virginia Tech, 2015-06)
    Energy storage, has widely been accepted as a means to provide capacity firming service to renewable sources of energy due to its capability to quickly start and shut down and its ability to have flexible ramping rates. Lithium Ion batteries in particular are of interest as their production cost is expected to significantly decrease over the next few years. In addition, Li-Ion batteries have high efficiency, high energy density and high cycling tolerance. These batteries are also used in electric vehicles whose penetration is expected to grow rapidly in the coming years. The social benefit of energy storage to provide energy balancing service to renewable producers is evident, especially in the context of a micro-grid where deviations from distributed generation sources can be handled locally. However, co-operation with renewable producers may not be automatically guaranteed and would depend on the amount of revenue generated by balancing such deviations. Storage may derive more benefit from choosing to operate independently. Balancing wind deviations would take capacity away from providing other high value services to the micro-grid community such as arbitrage and regulation service. The decision to enter the market and balance deviations for the wind producer is highly intertwined with the strategy adopted by the wind producer. Interactive problems in which the outcome of a rational agent's action depends on the actions of other rational players are best studied through the setup of a game-theoretic framework. A case-study is presented here using wind and electricity market data for a site in west Texas. Historical data is used to calculate expected pay-offs for the month of January. The columns in the following table are the available strategies for the wind producer and the rows are the available strategies for the energy storage. There are four possible combination of strategies, which are discussed next: The pay-off table provides the net revenues of the wind producer in the upper right corner and the net revenues of the energy storage in the lower left corner of each cell. Note that revenue from Production Tax Credits (PTC) is not included for the wind producer.
  • Computational Modelling of Solidity Effects on Blade Elements with an Airfoil Profile for Wind Turbines
    Yan, Haoxuan (Virginia Tech, 2015-06-08)
    The aim of this project is to investigate the aerodynamic performances of airfoil, especially NACA 4415, using the method of Computational Fluid Dynamics. The NACA 4415 was modeled and meshed in ICEM and then was simulated by using transition SST (shear stress transport) 4-equation model in ANSYS Fluent 15.0 with different Reynolds number and various angles of attack. Lift, drag, pressure distribution and wall shear stress were highly focused during post-processing. The computational results were compared with Xfoil and experimental data collected by The Ohio State University (OSU) in 1996. User Defined Functions (UDF) were also tested during the calculations in order to find the most optimal results. In addition to the isolated airfoil, this project also investigated the cascade effect of blade elements with a NACA 4415 airfoil profile with different solidities (ranges from 0.05 to 0.4). While the typical range for a 3-blade horizontal wind turbine is from 0.021 to 0.11 [1]. Aerodynamics of the airfoil will be influenced by different solidities.
  • A Wind Tunnel Study on the Aeromechanics of Dual-Rotor Wind Turbines
    Wang, Zhenyu; Tian, Wei; Sharma, Anupam; Hu, Hui (Virginia Tech, 2015-06)
    In the present study, we report our recent efforts to develop a novel dual-rotor wind turbine (DRWT) concept to improve aerodynamic efficiency of isolated turbines as well as wind farms. The DRWT concept employs a secondary, smaller, co-axial rotor with two objectives: (1) mitigate losses incurred in the root region of the main rotor by using an aerodynamically optimized secondary rotor, and (2) mitigate wake losses in DRWT wind farms through rapid mixing of turbine wake. Mixing rate of DRWT wake will be enhanced by (a) increasing radial shear in wind velocity in wakes, and (b) using dynamic interaction between primary and secondary rotor tip vortices. Velocity shear in turbine wake are tailored (by varying secondary rotor loading) to amplify mixing during conditions when wake/array losses are dominant. The increased power capacity due to the secondary rotor can also be availed to extract energy at wind speeds below the current cut-in speeds, in comparison to conventional single-rotor wind turbine (SRWT) design. For a DRWT system, the two rotors sited on the same turbine tower can be set to rotate either in the same direction (i.e., co-rotation DRWT design) or at opposite directions (i.e., counter-rotating DRWT design). It should be noted that a counter-rotating rotor concept (i.e., the rotors rotate at opposite directions) has been widely used in marine (e.g., counter-rotating propellers used by Mark 46 torpedo) and aerospace (e.g., Soviet Ka-32 helicopter with coaxial counter-rotating rotors) applications to increase aerodynamic efficiency of the systems. The recent work Ozbay et al. (2015) reveal that, with the two rotors in counter-rotating configuration (i.e., counter-rotating DRWT design), the downwind rotor could benefit from the disturbed wake flow of the upwind rotor (i.e., with significant tangential velocity component or swirling velocity component in the upwind rotor wake). As a result, the downwind rotor could harvest the additional kinetic energy associated with the swirling velocity of the wake flow. With this in mind, the effects of relative rotation direction of the two rotors on the aeromechanics performances of DRWTs (i.e., co-rotation DRWT design vs. counter-rotating DRWT design) and the turbulent mixing process in the DRWT wakes are also evaluated in the present study. The experimental study was performed in a large-scale Aerodynamics/Atmospheric Boundary Layer (AABL) Wind Tunnel located at the Aerospace Engineering Department of Iowa State University. Scaled DRWT and SRWT models were placed in a typical Atmospheric Boundary Layer (ABL) wind under neutral stability conditions. In addition to measuring the power outputs of the DRWT and SRWT systems, static and dynamic wind loads acting on the test models were also investigated to assess the effects of the secondary, smaller, co-axial rotor in either counter-rotating (rotors rotate at opposite directions) or co-rotating (rotors rotate at same direction) configuration on the power production performance and the resultant dynamic wind loads (both aerodynamic forces and bending moments) acting on the DRWT models. Furthermore, a high-resolution stereoscopic Particle Image Velocimetry (Stereo-PIV) system was also used to make both "free-run" and "phase-locked" measurements to quantify the transient behavior (i.e., formation, shedding and breakdown) of unsteady wake vortices and the flow characteristics behind the DRWT and SRWT models. The detailed flow field measurements were correlated with the power output data and dynamic wind loading measurements to elucidate underlying physics for higher total power yield and better durability of wind turbines operating in turbulent non-homogenous atmospheric boundary layer (ABL) winds.
  • Sustainability of the Wind Turbine Blade Manufacturing Process: A Bio-Based Alternative
    Ramirez, Katerin; Turcotte, David (Virginia Tech, 2015-06)
    Content : Globally, more than 23,000 wind turbines were manufactured in 2011 and there were 225,000 operational wind turbines by the end of 2012. United States' installed wind capacity will need to increase from 11.6GW to 300 GW to achieve the 20% wind production goal by 2030. To meet the increasing demand, not only more blades are being manufactured, but also longer blades of up to 100 meters long are being produced. The current stock of blades and the manufacturing process use petroleum based thermoset composites as the primary materials. The anticipated influx in disposal and manufacturing leads to health and environmental concern, given that the industry does not manufacture blades in a sustainable manner and has no practical way to recycle these blades. The main objective of this research project is to create an energy pathway for the sustainability of wind energy. In particular, this research is trying to develop a bio-based epoxy system for the wind turbine blade manufacturing process, in which the toughness, stiffness, durability and costs are comparable with petroleum based epoxy systems. The bio-derived thermoset will allow the industry to substitute a fossil fuel for vegetable oil, a more readily available feedstock, in the blade manufacturing process. In addition to the bio-based system, we want to realize the property of reworkability in both conventional and bio-based epoxies. The property of reworkability means that we could be able to thermally reprocess any anhydride-cured epoxy system with the addition of a special catalyst. It should allow for an effective recycling at the end of the blades' life cycle, presumably without the negative economic, health and environmental consequences that current disposal methods for thermoset composite impose. Overall, the expectation is to produce a high performance bio-based reworkable system which should enable manufacturing of blades that would be easily repaired, reworked or ground up for reuse with another purpose. The combination of these complementary technologies should improve sustainability both at the beginning and the end of the life cycle of a typical wind turbine blade. Approach to evaluation To evaluate the environmental, health and economic implications of replacing the petroleum based epoxy with a bio based epoxy, we use two different methodologies. The first one is a Life Cycle Cost Analysis (LCCA) to compare conventional and bio-based manufactured blades. The aim of the LCCA is to compare different alternatives in the manufacturing process and determine which one is the least costly while maintaining the same performance. We expect the bio-based manufacturing process to be very similar in terms of blade performance, but to differ in terms of the cost over the life cycle of the blades. The present value of all recurring costs and residual value of the blade at the moment of being disposed are calculated in order to determine the best long term manufacturing process.
  • A Cost Benefit Analysis of Electricity Generation
    Thomson, Heather; Kempton, Willett (Virginia Tech, 2015-06-08)
    This talk presents a cost-benefit analysis of three main fuels for electricity generation, namely coal, natural gas, and wind. This analysis incorporates social costs and benefits along with traditionally utilized private costs and benefits. The author has recently completed a study monetizing the visual and auditory amenity and disamenity of wind turbines and coal fired power plants, and also natural gas plants, by extension. This analysis utilizes that study and other recent studies on the impacts of electricity generation on water use, wildlife, and property values, among others, as well as other impacts well documented in the literature. Therefore it is the most current cost-benefit analysis of electricity generating facilities. It then examines the policy implications of the analysis.