Kite wind generator

KITE WIND GENERATOR

CHAPTER 1: INTRODUCTION

1.1 BACKGROUND

To overcome the limitations of current wind power technology, the KiteGen project

was initiated at Politecnico di Torino to design and build a new class of wind energy

generators in collaboration with Sequoia Automation, Modelway, and Centro

StudiIndustriali.The project focusis to capture wind energy by means of controlled

tethered airfoils, that is, kites; The KiteGen project has designed and simulated a small-

scale prototype ,The two kite lines are rolled around two drums and linked to two electric

drives, which are fixed to the ground. The flight of the kite is controlled by regulating

the pulling force on each line. Energy is collected when the wind force on the kite unrolls

the lines, and the electric drives act as generators due to the rotation of the drums. When

the maximal line length of about 300 m is reached, the drives act as motors to recover the

kite, spending a small percentage of the previously

This yo-yo configuration is under the control of the kite steering unit,which includes the

electric drives, the drums, and all of the hardware needed to control a single kite. The

aims of the prototype are to demonstrate the abil- ity to control the flight of a single kite,

to produce a significant amount of energy, and to verify the energy production levels

predicted in simulation studies

India is the home of 1.25 billon people i.e. 17.5% of the total world population,

which makes it second most populous country in world. India has the second fastest

growing economy of the world. India’s substantial and sustained economic growth over

the years is placing enormous demand on its energy resources. The electricity sector in

India had an installed capacity of 253.389 GW as of August 2014 .India became the

world's third largest producer of electricity in the year 2013 with 4.8% global share in

electricity generation surpassing Japan and Russia. Power development in India was first

started in 1897 in Darjeeling, followed by commissioning of a hydropower station at

Sivansamudram in Karnataka during 1902. Thermal power stations which generate

electricity more than 1000 MW are referred as Super Thermal Power Stations. India's

electricity generation capacity additions from 1950 to 1985 were very low when

compared to developed nations. Since 1990, India has been one of the fastest growing

SIET VIJAYAPURA EEE DEPT Page 1

KITE WIND GENERATOR

markets for new electricity generation capacity .India's electricity generation capacity has

increased from 179 TW-h in 1985 to 1053 TW-h in 2012. Wind energy is indigenous and

helps in reducing the dependency on fossil fuels. Wind occurrence is due to the

differential heating of the earth's crust by the sun. Approximately 10 million MW of

wind energy is continuously available to India. India's Power Finance Corporation

Limited projects that current and approved electricity capacity addition projects in India

are expected to add about 100 GW of installed capacity between 2012 and 2017. This

growth makes India one of the fastest growing markets for electricity infrastructure

equipment. Of the 1.4 billion people of the world who have no access to electricity in the

world, India accounts for over 300 million. The International Energy Agency estimates

India will add between 600 GW to 1,200 GW of additional new power generation

capacity before 2050 .To fill the needs of the energy of this population, India have to

look towards non conventional energy resource which can fill a huge demand of energy

generated by the population of India. India is fulfilling its 85% of energy demand from

the conventional recourses such as coal, nuclear energy, natural gas and petroleum which

generate many greenhouse gases. Green houses gases- carbon dioxide (CO2), sulfur

dioxide (SO2), nitrous oxide (N2O) etc. are produced in the energy generation process

are not only harmful for people’s health but it also deteriorates the environment vis-à-vis

global warming and hole in the ozone layer. Thus it is the need of time that country

should look towards the green & renewable methods for the generation of energy so that

environment can be saved from those harmful effects. Wind energy, solar energy,

biomass & other renewable methods can be used for the generation of energy to fulfill

the energy demands of the country. Present paper has divided into three parts; Sources of

the wind energy in India, future scope of the wind energy in India & Conclusion. Wind

power was widely available and not confined to the banks of fast-flowing streams, or later,

requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in

arid regions such as the American mid-west or the Australian outback, wind pumps provided

water for live stock and steam engines.

With the development of electric power, wind power found new applications in lighting

buildings remote from centrally-generated power. Throughout the 20th century parallel paths

developed small wind plants suitable for farms or residences, and larger utility-scale wind

generators that could be connected to electricity grids for remote use of power. Today wind

powered generators operate in every size range between tiny plants for battery charging at


KITE WIND GENERATOR

isolated residences, up to near-gigawatt sized offshore wind farms that provide electricity to

national electrical networks.

1.2MOTIVATION

A kite is traditionally a tethered heavier-than-air craft with wing surfaces that react against

the air to create lift and drag. A kite consists of wings, tethers and anchors. Kites have a

bridle to guide the face of the kite at the correct angle so the wind can lift it. A kite may have

fixed or moving anchors.

The lift that sustains the kite in flight is generated when air flows around the kite's surface,

producing low pressure above and high pressure below the wings. The interaction with the

wind also generates horizontal drag along the direction of the wind. The resultant force vector

from the lift and drag force components is opposed by the tension of one or more of the lines

or tethers to which the kite is attached. The anchor point of the kite line may be static or

moving.

The same principles of fluid flow apply in liquids and kites are also used under water.

CHAPTER 2: TYPES OF KITE WIND GENERATORS

2.1 Multiple unit kites


KITE WIND GENERATOR

Fig 2.1Multiple unit kites

A multiple unit kite may be made of a single wing, several wings, or several sub-kite

unitsarranged as trains, chains, coterie, single-branching, multiple-branching, arch-kite,

"ladder" mill dynamic kite-chain, or combinations of these patterns. World records for the

number of kites in a kite train are in the literature; teams of people are used to fly kites of

high-count sub-kite units.Parafoil stacks have been built with over 200 kite units.

2.2 Multiple pilot

Fig 2.2Multiple pilot

Large kite systems may require more than one pilot. In a team like the "Flying Squad" of nine

kite pilots each person might fly his own sub-kite while, as a team, its kites form a unified

display. One pilot may simultaneously fly several kites; the pilot with several kites forms one

kite system of two, three or more kites in the system.


KITE WIND GENERATOR

2.3 Airplane kites

Fig 2.3 Airplane kites

Large kite planes are finding an application in renewable energy generation.

2.5 Aqua-glider

Fig 2.4 Aqua-glider

These various-formed manned kites were kited behind tow boats over water. Air Force Lt.

Col. Bill Skliar in 1959 designed a biplane kite glider nicknamed Bayou Bird. In 1961, Tom

H. Purcell designed and flew an aluminum-framed Fleep-like Rogallo hang glider kite over

land; in 1962, he kited the same wing while over water. His effort was imaged and noted in

Skysurfer Magazine in its May/June issue of 1973, published by EAA inductee Michael

Markowski, author of Hang Glider's Bible. The 1962 Mike Burns SkiPlane and 1963

Dickenson wings closely matched the Purcell, Barry Hill Palmer, and the Charles Richard

NASA Paresev 1B wing; minor control sticks derived from the triangle control frame were


KITE WIND GENERATOR

used in each of these kites. These kites, towed high, could stop their kiting and release into a

glide.

CHAPTER 3: WORKING PRINCIPLE

3.1 OPERATION


KITE WIND GENERATOR

Fig 3.1OPERATION

The KSU is the unit that allows to automatically piloting a power kite.

At the very core of the project stays the software that, receiving data also from on-board

avionic sensors.

The KiteGen project has designed and simulated a small-scale prototype. The two kite

lines are rolled around two drums and linked to two electric drives, which are fixed to the

ground. The flight of the kite is controlled by regulating the pulling force on each line.

Energy is collected when the wind force on the kite unrolls the lines, and the electric

drives act as generators due to the rotation of the drums. When the maximal line length of

about 300 m is reached, the drives act as motors to recover the kite, spending a small

percentage of the previously

This yo-yo configuration is under the control of the kite steering unit, which includes the

electric drives the drums, and all of the hardware needed to control a single kite. The aims

of the prototype are to demonstrate the abil- ity to control the flight of a single kite, to

produce a signifi-cant amount of energy, and to verify the energy production levels

predicted in simulation studies. The potential of a similar yo-yo configuration is investi-

gated, by means of simulation results, in one or more kites linked to a single cable. Thus,

the control inputs are not only the roll angle ψ and the cable winding speed, as considered

in this article, but also the lift coefficient CL. For medium-to-large-scale energy

generators, an alter- native KiteGen configuration is being studied, namely, the carousel

configuration. In this configuration, several airfoils are controlled by their KSUs placed

on the arms of a verti- cal-axis rotor. The controller of each kite is designed to maximize


KITE WIND GENERATOR

the torque exerted on the rotor, which transmits its motion to an electric generator. For a

given wind direction, each airfoil can produce energy for about 300◦ of carousel rotation;

only a small fraction of the generated energy is used to drag the kite against the wind for

the remaining 60◦. According to our simulation results, it is estimated that the required

land usage for a kite generator may be lower than a current wind farm of the same power

by a factor of up to 30–50, with electric energy

Expert kite-surfers drive kites to obtain energy for propulsion. Control technology can be

applied to exploit this technique for electric energy generation.

The kite lines are linked to two electric drives. The flight of the kite is controlled by

regulating the pulling force on each line, and energy is generated as the kite unrolls the

lines.

The kite steering unit, which provides auto- matic control for KiteGen, includes the

electric drives, drums, and all of the hardware needed to control a single kite.

Production costs lower by a factor up to 10–20. Such potential improvement over

current wind technology is due to several aerodynamic and mechanical reasons.This

dependence is due to the fact that the aerodynamic forces on each infinitesimal section of

the blades are proportional to the square of its speed with respect to the air, and this speed

increases toward the tip of the blades. In KiteGen, the tethered airfoils act as the outer

portions of the blades, without the need for mechanical support of the tower and of the

less-productive inner blade portions. Indeed, a mean generated power of 620 kW is

obtained in the simulation reported for a single kite of 100-m2 area and 300-m line

length.

3.2 SYSTEM AND CONTROL TECHNOLOGIES NEEDED FOR

KITEGEN

3.2.1 Control Design


KITE WIND GENERATOR

The main objective of KiteGen control is to maximize energy generation

while preventing the airfoils from falling to the ground or the lines from

tangling. The control problem can be expressed in terms of maximizing a

cost function that predicts the net energy generation while satisfying

constraints on the input and state variables. Nonlinear model predictive

control (MPC) is employed to accomplish these objectives, since it aims to

optimize a given cost function and fulfill constraints at the same time.

However, fast implementation is needed to allow real-time control at the

required sampling time, which is on the order of 0.1 s. In particular, the

implementation of fast model predictive control (FMPC) based on set

membership approximation methodologies.

3.2.2 Model Identification

Optimizing performance for Kite- Gen relies on predicting the behavior

of the system dynamics as accurately as possible. However, since accurately

modeling the dynamics of a nonrigid airfoil is challenging, model-based

control design may not perform satisfactorily on the real system. In this case,

methods for identifying nonlinear systems can be applied to derive more

accurate models.

3.2.3 Sensors and Sensor Fusion

The KiteGen controller is based on feedback of the kite position and

speed vector, which must be mea- sured or accurately estimated. Each

airfoil is thus equipped with a pair of triaxial accelerometers and a pair


KITE WIND GENERATOR

fulfilled, the DVS gives the same accuracy as the theoreti-cal minimal

variance filter. Moreover, in the presence of modeling errors and

nonlinearities, the DVS guarantees stability and performs tradeoffs

between optimality and robustness, which are not achievable with EKF.

CHAPTER 4: APPLICATIONS

4.1 Teaching

The kite is frequently the vehicle for teaching aerodynamics, mathematics, art, history,

culture, materials, cooperation, physical education, and problem solving

4.2 Transport


KITE WIND GENERATOR

Long-distance travel across land, ice, and sea started centuries ago, but today significant tasks

of moving people and goods from point A to point B are occurring; this is so in great part

from the advances in kites and kite systems designs and technology, better understanding of

winds, and use of computers.In 1889 kite sailing was carefully instructed via controlling large

kite systems towing boats.

Free-flight cross-country hang gliding kites both in the hang glider style and the paraglider

style are permitting trips of hundreds of miles; records are recorded by the FAI. George

Pocock was an early pioneer in kites for transportation. NASA continues to explore free-

flying kites for delivering goods to earth surface and non-earth planet surfaces, including

Mars. There are several projects for using very large kites to sail cargo ships currently

underway: KiteSail(tm) and KiteShip along with a series of patents and improvements in

control of large ship-carried kite systems aim to save significant amounts of fuel.

4.3 Military

Kites have been used for military uses in the past for signaling, for delivery of munitions, for

free-flight kiting payloads from aircraft to ground positions, for kiting troops to points where

they could parachute to destinations, for underwater kiting via paravanes to perform various

underwater duties, for lifting payloads from one point to another, for raising rescue signals

from rafts or stressed areas, for raising communications antenna, and for observation by

lifting an observer above the field of battle, and by using kite aerial photography. Barrage

kites have been used in both open frame kites and kytoon types to defend against enemy

aircraft.

Kim Yu-Sin,a Korean general, in 637 C.E. rallied his troops to defeat rebels by kite lofting a

burning ball.Kites were also used by Admiral Yi of the Joseon Dynasty of Korea. During the

Japanese invasions of Korea , Admiral Yi commanded his navy with kites. His kites had

specific markings directing his fleet to perform his order. Admiral Yi was said to have over

300 such kites. The war eventually resulted in a Chinese and Korean victory; the kites played

a minor role in the war's conclusion.

4.4 Energy generation


KITE WIND GENERATOR

Both air and hydro kites are used to generate electricity; the kite is set in the stream of air or

water; various schemes are used to extract some of the stream's energy for converting that

energy to electricity.

A major research and development project called Makani Power, based in California and

funded by Google.org, is investigating the use of kites in harnessing high altitude wind

currents to generate electricity.Tidal kites operate underwater, using the tidal stream's greater

mass to generate far more electricity than available in wind-borne environments.

CHAPTER 5: ADVANTAGES & DISADVANTAGES

5.1 Advantages

The wind is free and with modern technology it can be captured efficiently

Once the wind turbine is built the energy it produces does not cause green house gases

or other pollutants

Although wind turbines can be very tall each takes up only a small plot of land. This

means that the land below can still be used. This is especially the case in agricultural

areas as farming can still continue


KITE WIND GENERATOR

Many people find wind farms an interesting feature of the landscape

Remote areas that are not connected to the electricity power grid can use wind

turbines to produce their own supply

Wind turbines have a role to play in both the developed and third world

5.2 Disadvantages The strength of the wind is not constant and it varies from zero to storm force. This

means that wind turbines do not produce the same amount of electricity all the time.

There will be times when they produce no electricity at all.

Many people feel that the countryside should be left untouched, without these large

structures being built. The landscape should left in its natural form for everyone to

enjoy

Wind turbines are noisy. Each one can generate the same level of noise as a family car

travelling at 70 mph

Many people see large wind turbines as unsightly structures and not pleasant or

interesting to look at. They disfigure the countryside and are generally ugly

When wind turbines are being manufactured some pollution is produced. Therefore

wind power does produce some pollution

Large wind farms are needed to provide entire communities with enough electricity.

For example, the largest single turbine available today can only provide enough

electricity for 475 homes, when running at full capacity.

CHAPTER 6: FUTURE SCOPE & CONCLUSION

6.1 Future scope

Trading torque for tension

Pumping

Changing tacks

Blowing in the wind

Military

6.2 conclusion


KITE WIND GENERATOR

Fig 6.2

It is a new class of wind energy generators able to overcome the main

limitations of the present Aeolian technology based on wind mills.

REFERENCE

1. "About KiteGen". 2010-05-08. Retrieved 2011-03-15.

2. Bardi, Ugo (2010-06-10). "Da Berzano, ilkitegen in costruzione"Retrieved2011-03-

15.

3. "Flugdrachen-SegelerzeugtbilligeWindenergie" [Kite produces cheap wind energy]

(in German). 2009-10-30. Retrieved 2011-03-15.

4. "A big energy reservoir: the altitude wind". Retrieved 2011-03-15.

5. "Kite Gen". Retrieved 2011-03-15.

6. "Kite Gen: KonzeptversprichtbilligeWindenergie" (in German). 2009-10-28.

Retrieved 16 March 2011.

7. "NASA untersuchtMöglichkeitfürWindfarmen in luftigenHöhen" (in German). 2010-

12-22. Retrieved 15 March 2011.


KITE WIND GENERATOR

8. "Campagna "ScoprireilNucleare"" (in Italian). 2011-03-01. Retrieved 16 March

2011.

9. Jewkes, Stephen; Lalor, Dan (12 September 2012). "Third buyer interested in Alcoa

Sardinia smelter". Reuters. Retrieved 27 September 2012.

10. Sapellani, Niccolò(20 September 2012). "Alcoa, ilterzopretendente è la KiteGen:

"Produrrealluminioutilizzandoilvento". IlFattoQuotidiano. Retrieved 27 September

2012.

11. Jucca, Lisa "Italy's Sardinia struggles to leave state aid behind". Reuters. Retrieved

27 September 2012


Engineering

Kite wind generator