There has been rising popularity with Alternate Energy Sources, in the past few decades with the Global Energy Demand and Supply Situation being brought into the spotlight. Although in a recent article published by the International Renewable Energy
Agency (IRENA) [1] , future estimates of renewable energy contribution stands at Hydroelectric power leading the way with a 17% contribution to World Renewable Energy Consumption, Wind Power lags not too far behind at 14% contribution to Global Renewable Energy. Wind Power is primarily supplied through the use of Horizontal Axis Wind Turbines, among which the 3-blade design is the most frequently used. Although the wind turbine holds the rank of the most commonly used method, many studies show that higher wind speeds exist at altitudes above the reach of current wind turbines.
This report aims to take a further look into this, by studying various papers and journals on this subject along with the correlation of wind speeds to different altitudes on the Earth’s surface, and by looking into the various High Altitude Wind Energy Systems particularly, the Kite system which is the most successful till date. Also, the general wind speed distributions all over the world using the Weibull Parameters are looked into briefly.
The design considerations an fluid modelling of a curved airfoil used in typical kite power system is analysed. Finally, a brief cost analysis on existing wind turbine technology with kite power systems is undertaken. A list of references at the end of the report establishes the sources and citations regarding this report and also gives credit to the various papers and journals used for the compilation of this work.
Table of Contents
1. INTRODUCTION
2. WIND ENERGY DISTRIBUTION ON EARTH’S SURFACE
2.1 WIND SPEED AS A FUNCTION OF POWER OUTPUT
2.2 WIND SPEED DISTRIBUTION GEOGRAPHICALLY
3. PROBLEMS WITH CONVENTIONAL WIND TURBINES
4. HIGH ALTITUDE WIND POWER GENERATION SYSTEMS
5. KITE POWER SYSTEMS
5.1 DESIGN CONSIDERATIONS AND FLUID MODELLING OF HIGH ALTITUDE KITE SYSTEM
5.2 OPTIMAL OPERATIONAL TETHER LENGTH
6. ENERGY COST ANALYSIS AND SUMMARY
7. CONCLUSION
8. REFERENCES
Objectives & Core Topics
This report aims to evaluate the potential of High Altitude Wind Power Generation (HAWPG) systems as a viable alternative to conventional wind turbines by examining wind speed correlations at varying altitudes and analyzing the fluid dynamics and cost-efficiency of tethered kite power systems.
- Wind energy distribution and boundary layer characteristics.
- Limitations of conventional horizontal axis wind turbines (HAWT).
- Technical design considerations for high-altitude kite systems.
- Fluid modelling and aerodynamic performance of curved airfoils.
- Economic analysis comparing kite-based systems to current wind technology.
Excerpt from the Book
1. INTRODUCTION
Although, Wind Energy has come a long way since its conception, it accounts for a relatively small portion of Global Electricity supply, at around 4% in 2014 [2] . Advancements in Computer Aided Design have allowed for more complex curvatures and Computer Based Simulations have reduced testing costs and allowed for greater accuracy during approximations. As Wind Turbines tower to greater and greater heights , they produce greater amounts of Power accordingly, but this comes at a price. With ever increasing height comes problems associated with Structural Strength and Deeper, Stronger Foundations. Also, to be taken into account is the unique boundary layer formed on the earth's surface as well as a result of blowing wind. The no slip condition that is a fundamental property of flow fields on rigid bodies also applies to the earth and this ‘no slip ’ region is located very close to the surface of the earth. The atmosphere is a complex system with variations in temperature, pressure and wind speed as a function of Altitude. The tallest Wind Turbine of today is located in Gaildorf, Germany erected by ‘Max Bögl Wind AG’ measures a height of 246.9 meter (809 ft) and costs of $ 81 Million USD with an estimated revenue generation of $ 7.5 Million USD per year [3] . This height, although quite large no doubt, is only a fraction of what high altitude systems are aiming to achieve.
Since the method used in high energy systems is the tethered airborne setup, large foundations and heavy structural reinforcements are not required which account for large savings in initial set-up costs. Also, greater heights can be reached by opting for the tether approach. The wind energy available at 800 meters is 4 times that available at an altitude of 80 meters [4] , so these high speed winds can be put to use. The development of interest to this project is the Kite Power System which will looked into in detail.
Summary of Chapters
1. INTRODUCTION: Outlines the limitations of current wind turbine technology and introduces high-altitude tethered kite systems as an alternative.
2. WIND ENERGY DISTRIBUTION ON EARTH’S SURFACE: Discusses the planetary boundary layer and how wind speed and power density vary with altitude.
2.1 WIND SPEED AS A FUNCTION OF POWER OUTPUT: Explains the cubic relationship between wind speed and energy generation.
2.2 WIND SPEED DISTRIBUTION GEOGRAPHICALLY: Details the use of Weibull parameters to analyze wind frequency distribution globally.
3. PROBLEMS WITH CONVENTIONAL WIND TURBINES: Identifies structural, land-use, and efficiency challenges associated with traditional ground-based wind turbines.
4. HIGH ALTITUDE WIND POWER GENERATION SYSTEMS: Introduces HAWPG systems and the use of tethered airfoils to capture high-altitude wind.
5. KITE POWER SYSTEMS: Reviews the mechanics and operational principles of kite-based energy generation.
5.1 DESIGN CONSIDERATIONS AND FLUID MODELLING OF HIGH ALTITUDE KITE SYSTEM: Describes the aerodynamic simulation and design parameters for kite wings.
5.2 OPTIMAL OPERATIONAL TETHER LENGTH: Analyzes the balance between altitude and tether forces to find optimal operating lengths.
6. ENERGY COST ANALYSIS AND SUMMARY: Provides a comparative cost estimate between conventional wind farms and kite power technology.
7. CONCLUSION: Summarizes the potential of HAWPG systems as a future supplement to renewable energy infrastructure.
8. REFERENCES: Lists the sources and citations used throughout the literature review.
Keywords
Wind Energy, High Altitude Wind Power, Kite Power Systems, Renewable Energy, Aerodynamics, Fluid Modelling, Weibull Distribution, Tethered Airfoils, Wind Turbines, Planetary Boundary Layer, Energy Efficiency, Crosswind, Structural Load, Sustainable Energy, Power Density.
Frequently Asked Questions
What is the primary focus of this literature review?
The report explores High Altitude Wind Power Generation (HAWPG) systems as a solution to the limitations of traditional wind turbines, specifically focusing on the feasibility and mechanics of kite power systems.
What are the core thematic areas of the research?
Key areas include the relationship between wind speed and altitude, the fluid dynamics of airfoils, environmental impact, and the comparative economic efficiency of tethered energy systems.
What is the main research question or goal?
The goal is to determine if tethered airborne systems can effectively capture high-altitude winds to generate power more efficiently and cost-effectively than conventional ground-based wind towers.
Which scientific methodologies are employed?
The study utilizes theoretical analysis of wind energy distribution, Reynolds Averaged Navier-Stokes (RANS) simulations for airfoil modelling, and cost estimation based on existing wind farm capacity factors.
What topics are covered in the main body of the report?
The main body covers wind speed distribution on Earth, current technical challenges with conventional wind turbines, design considerations for kites, and economic projections for large-scale kite farm deployment.
Which keywords best characterize this work?
The work is defined by terms such as Wind Energy, Kite Power, Aerodynamics, Power Density, and High Altitude Wind Power Generation.
Why is the "no slip" condition relevant to this research?
It explains why wind speeds are lower near the Earth's surface due to surface friction, thereby justifying the need for high-altitude systems that operate above this boundary layer.
How does a kite system differ from a traditional wind turbine regarding space?
Kite systems require significantly less ground infrastructure and land area, as they do not need heavy towers and can be arranged to mitigate the wake turbulence effects found in traditional wind farms.
What is the role of the tether length in kite power efficiency?
Tether length must be optimized because while higher altitudes offer higher power density, longer tethers introduce gravitational and aerodynamic drag that eventually diminishes the net power gain.
- Citation du texte
- Noel Dsouza (Auteur), 2017, A Literature Review on High Altitude Wind Power-Generation Systems, Munich, GRIN Verlag, https://www.grin.com/document/388700
