Browsing by Subject "Wind energy"

Now showing 1 - 14 of 14

Analysis of storing wind energy for periods of seconds to hours in ERCOT
(2010-08) Weber, Robert Arthur, 1983-; Baldick, Ross; Ghosh, Joydeep
Wind energy has dramatically changed the energy portfolio of Texas and more specifically, a region covering 75% of the state designated as ERCOT (Electric Reliability Council of Texas). Hardly existent at all ten years ago, the amount of capacity the wind farms provide is over 9000MW and accounts for 10% of the total generation. Due to the intermittent nature of wind and limitations of transmission lines, short and long term storage of this energy would benefit wind farms and the grid as a whole. This paper studies the relationship between wind, storage and real time electricity prices by analyzing prices and simulating a wind farm with different wind storage strategies over the course of a year. Based on these simulations, it is found that an ideal storage medium with no losses could be in the money for $17.50/kW for long term storage and $1,998/kW for short term storage for prices similar to 2009-2010.
Analysis of the temperature effects related to power generation surrounding wind turbine installations southwest of Abilene, Texas
(2022-12-02) Crues, Ashton Grace; King, Carey Wayne, 1974-; Yang, Zong-liang; Helper, Mark
The wind farms in Texas southwest of Abilene are some of the oldest in the United States and have provided many researchers the opportunity to study the long-term effects of wind turbines on the environment. The principal objective of this thesis was to compare 2020 maximum and minimum land surface temperatures on both high- and low-generation days within and adjacent to an Abilene wind farm. This work shows the impact of turbine placement on differential temperature ranges and on diurnal temperatures and temperature ranges between and within high- and low-power generation days. I used National Aeronautics and Space Administration (NASA) 1-kilometer temperature data and QGIS for temperature differential, defined as the temperature difference at a specific location within a specific area compared to the same average difference for a control area outside of turbine influence. I compared temperature differentials within 1 km of wind turbines to those at 5 km or greater from the nearest turbine to define areas inside versus outside of turbine influence. First, the LST datasets show a statistically significant lower average temperature within wind farms compared to the average outside the farms for the high-generation day. Second, the LST datasets show a small but statistically significant higher average temperature within wind farms for low-generation day minimum temperatures. Third, there is no statistically significant average temperature difference between wind farms and areas outside of them when considering low-generation day maximum temperatures. The between generation days analysis reveals that the average difference in temperatures between high- and low-generation days within the wind farms was less than this same average difference outside of the wind farms. The high-generation day was associated with a slightly greater average range of diurnal temperature within wind farms compared to the average diurnal temperature range outside of the wind farms. The same isn’t true for the low-generation day, where there was no statistically significant difference in average diurnal temperature range. The Horse Hollow wind farm and adjacent turbines on high power generation days are associated with a noticeable land surface temperature decrease within the wind farm compared to the surrounding area.
Avian mortality and wind energy production in Texas
(2007-12) Ford, Scott A.; Paterson, Robert G.
Wind energy development and its stigma of avian mortality provide a case for exploring the complexities that can occur between science, law, politics, and planning. The present method of measuring mortality appears flawed and may hamper the ability of resource agencies, the public, and industry in making educated decisions about siting wind farms and protecting species. The U.S. Fish and Wildlife Service has the ability to take an active role and affect a project already constructed. The Migratory Bird Treaty Act appears to keep the issue of avian mortality within the minds of wind energy developers. Protecting species on the brink of extinction is codified in the Endangered Species Act, which seems to be well suited for protecting most species. The significance of avian mortality can be linked to public perceptions. The industry in Texas has taken the approach of not sharing avian-related data, except in very few instances. Providing such substantial federal incentives through the Production Tax Credit rather than direct federal funding bypasses the National Environmental Policy Act and its requirement that federal governments consider impacts to the environment.
Cost-conscious control strategies for wind turbine systems
(2017-05) Ma, Zheren; Chen, Dongmei, Ph. D.; Baldick, Ross; Djurdjanovic, Dragan; Longoria, Raul G.; Barr, Ronald
Wind energy is one of the most abundant renewable energy sources that can meet future energy demands. Despite its fast growth, wind energy is still a marginal player in electricity generation. The key issues preventing wider deployment of wind turbines include low energy conversion efficiency, high maintenance cost, wind intermittency and unpredictability etc. These issues lead to considerably higher cost of wind power compared to that of traditional power sources. This work is focused on control designs to overcome the above challenges. First, control algorithms are developed for energy capture maximization. During partial load operation, wind turbine rotor speed is continuously adjusted to remain optimal operation by manipulating the electromagnetic torque applied to the generator. In this dissertation, a dynamic programming based real-time controller (DPRC) and a gain modified optimal torque controller (GMOTC) are developed for faster convergence to optimal power operation under volatile wind speed and better robustness against modeling uncertainties. Secondly, fatigue loading mitigation techniques are developed to reduce the maintenance cost of a wind turbine. During partial load operation, a generator torque-based fatigue mitigation method is devised to reduce the impact of exacerbated tower bending moments associated with the resonance effect. During full load operation, a H₂ optimization has been carried out for gain scheduling of a Proportional-Integral blade pitch controller. It improves speed regulation and reduces drivetrain fatigue loading with less oscillations of turbine rotor speed and generator torque. Thirdly, battery energy storage systems (BESS) have been integrated with wind turbines to mitigate wind intermittence and make wind power dispatchable as traditional power sources. Equipped with a probabilistic wind speed forecasting model, a new power scheduling and real-time control approach has been proposed to improve the performance of the integrated system. Finally, control designs are oriented to wind turbine participation in grid primary frequency regulation. The fast active power injection/absorption capability of wind turbine enables it to rapidly change its power output for stablizing the grid frequency following an sudden power imbalance event. In addition to quick response to grid frequency deviation event, the proposed controller guarantees turbine stability with smooth control actions.
Do local communities benefit from renewable energy? : evidence from the U.S. wind industry
(2020-05-06) Daniels, Dashiell McGregor; Olmstead, Sheila M.
Prior work estimates particular economic benefits associated with wind energy development in the United States, but few papers provide econometric estimates. Combining a dataset of geolocated windmills throughout the continental U.S. with county-level statistics on personal income and government revenue, I estimate the effect of a one megawatt increase in county-level installed wind power capacity using an instrumental variables approach. Panel two-stage least squares estimates demonstrate a 0.13 percent increase in personal income and a 0.25 percent increase in county government revenue per megawatt of installed capacity. Estimated gross economic benefits from 2001 to 2017 total to roughly $1,040 billion in additional personal income and $38 billion in additional government revenue
Dynamic models for wind power plants
(2011-08) Singh, Mohit, 1982-; Santoso, Surya; Grady, William M.; Driga, Mircea; Muljadi, Eduard; Longoria, Raul G.
Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. In order to determine how realistic model performance is, the performance of the one of the models (doubly fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.
Economic analysis of wind and solar energy sources of Turkey
(2011-05) Erturk, Mehmet; Groat, Charles G.; Jablonowski, Christopher J.
Renewable energy sources have become very popular in the last years in electricity generation thanks to the technological developments, the increase in the price of fossil fuels and the environmental concerns. These factors have also prompted Turkey to utilize her very rich renewable energy sources to meet the demand increasing around 7% annually. In this study, solar and wind energy potential of Turkey is analyzed in terms of its economics to find out whether these sources are real alternatives to fossil fuels in electricity generation. Before this analysis, wind and solar energy technologies and costs and wind and solar energy potential of Turkey are discussed. Then, models are set up for five technologies which are onshore wind, offshore wind, solar PV, solar trough and solar tower technologies models to calculate cash flows which are used to calculate payback, NPV, IRR, LCE and shut-down price to conduct economic analysis. In addition to base case scenario, uncertainty analysis is done for the most promising technologies which are onshore wind and solar tower technologies by evaluating NPV and LCE under uncertain environment. The main finding of these analyses is that only onshore wind projects are attractive in Turkey; none of other technologies is attractive. However, with a minor increase in the regulated price for solar thermal electricity, tower plant projects will also be attractive.
Feasibility study of an integrated wind and solar farm by evaluating the wind turbine shadows
(2012-05) Shanghavi, Sahil; Grady, W. M.; Santoso, Surya
This thesis analyzes the feasibility of having an integrated wind and solar farm to optimize the use of land resources and capital investment by evaluating the effect that wind turbine shadows have on the area surrounding them. Two methods are used to predict shadow impact. The first method is based on the traditional textbook “Clear Sky” equations, which have maximum sensitivity to shadows because the method considers every day to be a perfect day. The second method uses measured global-horizontal and diffuse-horizontal solar radiation in units of W/m2, which take into account the true variations of daily conditions. The calculations are performed for 1 square meter surfaces, over different assumed areas of a wind power plant, for every second of the day. For purposes of shadow calculations, the tip-top height (i.e., tower height plus blade length) is used. All calculations are performed with the specifications of a GE 1.5 MW wind turbine, which is the most commonly used wind turbine in USA.
Harvesting wind energy using a galloping piezoelectric beam
(2011-05) Mahadik, Rohan Ram; Sirohi, Jayant; Bennighof, Jeffrey
Galloping of structures such as transmission lines and bridges is a classical aeroelastic instability that has been considered as harmful and destructive. However, there exists potential to harness useful energy from this phenomenon. The study presented in this paper focuses on harvesting wind energy that is being transferred to a galloping beam. The beam has a rigid prismatic tip body. Triangular and D-section are the two kinds of cross section of the tip body that are studied, developed and tested. Piezoelectric sheets are bonded on the top and bottom surface of elastic portion of the beam. During galloping, vibrational motion is input to the system due to aerodynamic forces acting on the tip body. This motion is converted into electrical energy by the piezoelectric (PZT) sheets. A potential application for this device is to power wireless sensor networks on outdoor structures such as bridges and buildings. The relative importance of various parameters of the system such as wind speed, material properties of the beam, electrical load, beam natural frequency and aerodynamic geometry of the tip body is discussed. A model is developed to predict the dynamic response, voltage and power results. Experimental investigations are performed on a representative device in order to verify the accuracy of the model as well as to study the feasibility of the device. A maximum output power of 1.14 mW was measured at a wind velocity of 10.5 mph.
Impacts of windmill traffic on pavement structures
(2010-08) Grebenschikov, Sergey; Cicil, Architectural, and Environmental Engineering; Prozzi, Jorge Alberto; Prozzi, Jolanda; Machemehl, Randy B.
This report focuses on the impacts of traffic generated as a result of the windmill on pavement structures. The wind energy industry is a fast growing sector of the U.S. economy. Lately concerns have been raised over the transportation of heavy windmill components on the pavement infrastructure. This report analyzes the impacts of windmill traffic on two pavement structures in Texas: 1) rural interstate facility, and 2) rural collector roadway facility. Windmill traffic was disaggregated by windmill component and categorized into eight vehicle classes. Two traffic scenarios were developed and a damage ratio for pavement rutting was developed. Based on the rutting damage ratio, results showed that windmill traffic has a significant impact on rural collector facilities when compared against normal truck traffic activity. Meanwhile, impacts on rural interstate facilities were determined to be insignificant when compared to normal truck traffic activity.
An integrated energy storage scheme for a dispatchable wind and solar powered energy system
(2009-12) Garrison, Jared Brett; Webber, Michael E., 1971-; Schmidt, Philip
Wind and solar technologies have experienced rapid market growth recently as a result of the growing interest for implementation of renewable energy. However, the intermittency of wind and solar power is a major obstacle to their broader use. The additional risks of unexpected interruptions and mismatch with demand have hindered the expansion of these two primary renewable resources. The goal of this research is to analyze an integrated energy system that includes a novel configuration of wind and solar coupled with two storage methods to make both wind and solar sources dispatchable during peak demand, thereby enabling their broader use. Named DSWiSS for Dispatchable Solar Wind Storage System, the proposed system utilizes compressed air energy storage (CAES) that is driven from wind energy and thermal storage supplied by concentrating solar thermal power in order to achieve this desired dispatchability. Although DSWiSS mimics the operation of a typical CAES facility, the replacement of energy derived from fossil fuels with energy generated from renewable resources makes this system unique. While current CAES facilities use off peak electricity to power their compressors, this system uses power from wind turbines. Also, rather than using natural gas for heating of the compressed air before its expansion through a turbine, DSWiSS uses solar thermal energy and thermal storage. For this research, two models were created; the first is a dynamic model of a 1.5 MW variable speed wind turbine, programmed in PSCAD/EMTDC, that utilizes rotor resistive control to maintain rated power output. This model simulates the dynamic response of the wind turbine to changing wind conditions as well as the nominal performance parameters at all wind speeds. The second model is a steady state thermodynamic simulation of the turbomachinery power unit in the DSWiSS facility. By assuming conditions similar to those of a currently operating CAES facility in McIntosh, Alabama, the model calculates the performance parameters of DSWiSS and estimates the relative energy input requirements. By combining these models with a levelized lifetime cost analysis estimates of the power system performance and the cost of energy for the DSWiSS facility were estimated. The combination of these components yielded an efficiency greater than 46% for the main power block and a nearly equal utilization of both renewable resources. It was also estimated that the overall system is only slightly more expensive per unit of electricity generated than the current technologies employed today, namely coal, nuclear, and natural gas, but is comparable to a stand-alone solar thermal facility. However, this economic analysis, though accurate with regard to the technologies chosen, will not be complete until cost values can be placed on some of the externalities associated with power generation such as fuel cost volatility, national security, and emissions.
Next generation wind energy harvesting to power bridge health monitoring systems
(2012-05) Zimowski, Krystian Amadeusz; Crawford, Richard H.; Wood, Kristin L.
The research reported in this thesis is part of a project to develop a remote wireless sensing network for monitoring the health of highway bridges. Remote health monitoring that does not require direct human observation has many advantages in terms of cost and increased productivity. However, bridges that cannot be easily connected to the power grid require alternative means of acquiring power. This thesis describes the design of a wind energy harvester to power a particular component in the sensor network, the wireless router. The work discussed in this thesis provides a review of relevant literature and development of a detailed analytical modeling of wind turbine behavior. The analytical model provides key information on sizing generators and choosing appropriate wind turbine dimensions to provide the required amount of power. The analytical model also distinguishes the performance of vertical and horizontal axis wind turbines. The model is verified through design and testing of a first generation prototype and benchmarking of a commercially available turbine. Based on these results, the design of the next generation wind harvesting system is described. A new methodology to design non-destructive attachment systems is also discussed.
Optimal control of wind turbines for distributed power generation
(2015-08) Shaltout, Mohamed Lotfi Eid Nasr; Chen, Dongmei, Ph. D.; Longoria, Raul G.; Crawford, Richard H.; Deshpande, Ashish D.; Malikopoulos, Andreas A.; Pratap, Siddharth B.
Wind energy represents one of the major renewable energy sources that can meet future energy demands to sustain our lifestyle. During the last few decades, the installation of wind turbines for power generation has grown rapidly worldwide. Besides utility scale wind farms, distributed wind energy systems contributes to the rise in wind energy penetration. However, the expansion of distributed wind energy systems is faced by major challenges such as the system’s reliability in addition to the environmental impacts. This work is intended to explore various control algorithms to enable the distributed wind energy systems to face the aforementioned challenges. First of all, a stall regulated fixed speed wind turbine augmented with a variable ratio gearbox has been proven to enhance the wind energy capture at a relatively low cost, and considered as an attractive design for small wind energy systems. However, the high reliability advantage of traditional fixed-speed wind turbines can be affected by the integration of the variable ratio gearbox. A portion of this work is intended to develop a control algorithm that extends the variable ratio gearbox service life, thus improves overall system reliability and reduces the expected operational cost. Secondly, a pitch regulated variable speed wind turbines dominates the wind energy industry as it represents a balance between cost and flexibility of operation. They can be used for midsized wind power generation. Optimizing its wind energy capture while maintain high system reliability has been the one of the main focuses of many researchers. Another portion of this work introduces a model predictive control framework that enhances the reliability of pitch regulated variable speed wind turbines, thus improves their operational cost. Finally, one of the major environmental challenges facing the continuous growth of wind energy industry is the noise emitted from wind turbines. The severity of the noise emission problem is more significant for small and medium sized wind turbines installed in the vicinity of residential areas for distributed power generation. Consequently, the last portion of this work is intended to investigate the potential of wind turbine control design to reduce noise emission in different operating conditions with minimal impact on power generation
The unlikely success of green power in America’s reddest state, and its uncertain future
(2012-05) Gerdau, Axel; Dahlby, Tracy; Alves, Rosental
This narrative chronicles the development of the utility scale wind industry in Texas from the perspective of the people who made it possible. It also looks ahead at the challenges facing the most mature green power sector in the United States.