Self-study report presented byAbhishek GawandeRoll No. – 04 (A)Topic : “Wind Farms” Under the supervision of Dr D J Tidke

G.H. Raisoni College of Engineering, NagpurDepartment of Mechanical Engineering

(An autonomous Institute under UGC act 1956 & affiliated to RTMNU, Nagpur)

Introduction Site Selection Types of wind farmsWorkingParts of Wind TurbineWind PotentialFacts & FiguresPros & Cons

Introduction Site Selection Types of wind farmsWorkingParts of Wind TurbineWind PotentialFacts & FiguresPros & Cons

INTRODUCTION

A 'wind farm’ is a group of wind turbines in the same location used for production of electric power.

Wind farms can take up a lot of land, but most of the land can still be used for other things at the same time, such as farming or to graze animals.

A large wind farm may consist of a few dozen to several hundred individual wind turbines, and cover an extended area of hundreds of square miles (square kilo-meters).

Individual turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network.

At a substation, this medium-voltage electrical current is

increased in voltage with a transformer for connection to the high voltage transmission system

The electricity from a wind farm goes to the electric

company’s power lines, which carry it to our homes and businesses.

How Winds are Generated??

The wind is a by-product of solar energy.

Approximately 2% of the sun's energy reaching the earth is converted into wind energy.

The surface of the earth heats and cools unevenly, creating atmospheric pressure zones that make air flow from high-to low-pressure areas.

Essential requirements for setting up a wind farm

The essential requirements for establishment of a wind farm for optimal exploitation of the wind are

• High wind resource at particular site.

• Adequate land availability.

• Suitable terrain and good soil condition.

• Proper approach to site.

•Suitable power grid nearby.

Off-shore On-shore

Types of Wind Farms

Onshore

• Onshore turbine installations in hilly or mountainous regions tend to be on ridgelines generally three kilo-meters or more inland from the nearest shoreline. This is done to exploit the so called topographic acceleration as the wind accelerates over a ridge.

• Onshore wind power has an impact on the environment chiefly in form of noise pollution, visual pollution and harm to birds.

Off-Shore

• Offshore wind development zones are generally considered to be ten kilo-meters or more from land.

• Offshore wind turbines are less obtrusive than turbines on land, as their apparent size and noise is mitigated by distance.

• Offshore installation is more expensive than onshore but this depends on the attributes of the site.

Wind Turbine Components

Parts Of Wind Turbine

Classification of Wind Turbines

There are two main types of wind turbines used :

A) Horizontal Axis Wind

Turbine

B) Vertical Axis Wind Turbine

HAWT :

Has rotor shaft and electrical generators at the top of the tower. Small Turbines use wind vane to point to the wind direction

Contains gearbox to convert the slow wind speed to quicker rotation to drive the generator

Three bladed turbines are mainly used. The most important reason is the stability of the turbine

Height of towers range from 200 ft to 300 ft

The Rpm of the blades are around 10 -12

It has a Control System that shuts down the wind generator during heavy wind to prevent damage.

Horizontal Axis Wind Turbine

Advantage and Disadvantage (HAWT)

Has high Efficiency than VAWT (vertical axis wind turbine) as blades are perpendicular to the air flow thus receives maximum wind power and due to its height it receives full speed of the air (as for every rise of 10 meters the air speed increases by 34%)

Difficult to transport, install and repair due to its large size. 20% of the cost increases due to its size factor

VAWT :

• The rotor is arranged vertically .

• The wind turbines are difficult to mount over the top and hence they are placed near the base.

• It has guy wires to hold it in places

Vertical Axis Wind Turbine

Advantage and Disadvantage of VAWT

They have low start up speeds like 10 km/hr and they can easily

be used where taller structures are prohibited

Due to low height its easy to transport and cost reduces

It produces less power as they are mounted near the base so

they cannot get the full speed of wind and near the base the air

gets turbulent due to presence of various objects and hence its

efficiency is less than HAWT

Parts are placed under the structures and hence maintenance is

difficult

Calculation of Wind Power•Power in the wind

– swept area, A– wind speed, V– air density,

R

Swept Area: A = πR2 Area of the circle swept by the rotor (m2).

Power in the Wind = ½ρAV3

•Variability is a major problem associated with wind power.

•If the wind is too weak, very little power is generated.

•But, if its too strong, the large forces exerted may cause structural

damage, so many turbines shut down in high winds.

Facts & Figures•Total worldwide installed capacity of wind turbines in 2008: 121 gigawatts .This represents about 1% of total power generation from all sources.

•Country with highest wind energy use: US with 29 gigawatts

•States with largest wind turbine generating capacity: Texas (8.4 gigawatts), Iowa (3.0 gigawatts), and California (2.8 gigawatts) account for almost one half of the US total wind capacity.

•World’s largest wind turbine: Enercon E-126 generates 6 MW (1 MW= 1 million watts), with a rotor diameter of over 400 ft.

•World’s largest windfarm: Horse Hollow Energy Center, spread over 47,000 acres in Nolan and Tayler counties in Texas , has 421 wind turbines generating 735 MW of electricity. 

Wind Farm Output across the World

The development of wind power in India began in the 1990s, and has significantly increased in the last few years.

India has the fifth position in the generation of wind electric generation.

The total estimated wind power potential in India is about 45195MW.

Wind power accounts for 6% of India's total installed power capacity, and it generates 1.6% of the country's power.

Wind Potential In India

Pros & Cons

ProsRenewableEnvironment

friendlySafe InexhaustibleInexpensiveLow Operation &

maintenance costs.

ConsWind speed variable

and unreliableWind turbines

produce large amounts of noise pollution

Dangerous for birds

REFERENCES

•http://en.wikipedia.org/wiki/Wind_farm

•http://science.howstuffworks.com/environmental/green-science/wind-power7.htm

•http://www.thewindpower.net/

•http://www.suzlon.com/

•http://www.indianwindpower.com/

•http://www.inwea.org/

THANK YOU!