Wind Energy Presented By: Ali Hassan HafeezAnumNaz Junaid Ahmad Joya Muhammad Usman WajihaAmjad Zia Ur Rehman
What is Energy ? • Physicists, who are scientists who study force, motion and energy, say that energy is the ability to do work, and work is moving something against a force, like gravity. There are a lot of different kinds of energy in the universe, and that energy can do different things. • Energy can be found in many things, and takes many forms. There is a kind of energy called kinetic energy in objects that are moving. There is something that scientists call potential energy in objects at rest that will make them move if resistance is removed.
Sources Of Energy • Sun • Water • Coal • Wind • Geo-Thermal • Bio-Mass • Tidal • Nuclear
Introduction • All renewable energy (except tidal and geothermal power), ultimately comes from the sun • The earth receives 1.74 x 1017 watts of power (per hour) from the sun • About one or 2 percent of this energy is converted to wind energy (which is about 50-100 times more than the energy converted to biomass by all plants on earth
Introduction contd. • Differential heating of the earth’s surface and atmosphere induces vertical and horizontal air currents that are affected by the earth’s rotation and contours of the land WIND. e.g.: Land Sea Breeze Cycle
Introduction contd. • A typical 600 kW wind turbine has a rotor diameter of 43-44 meters, i.e. a rotor area of some 1,500 square meters. • The rotor area determines how much energy a wind turbine is able to harvest from the wind. • Since the rotor area increases with the square of the rotor diameter, a turbine which is twice as large will receive 22 = 2 x 2 = 4times as much energy.
Introductioncontd. • To be considered a good location for wind energy, an area needs to have average annual wind speeds of at least 12 miles per hour.
History • 1 A.D. • Hero of Alexandria uses a wind machine to power an organ • ~ 400 A.D. • Wind driven Buddhist prayer wheels • 1200 to 1850 • Golden era of windmills in western Europe – 50,000 • 9,000 in Holland; 10,000 in England; 18,000 in Germany • 1850’s • Multi-blade turbines for water pumping made and marketed in U.S.
History contd. • 1882 • Thomas Edison commissions first commercial electric generating stations in NYC and London • 1900 • Competition from alternative energy sources reduces windmill population to fewer than 10,000 • 1850 – 1930 • Heyday of the small multi-blade turbines in the US midwast • As many as 6,000,000 units installed • 1936+ • US Rural Electrification Administration extends the grid to most formerly isolated rural sites • Grid electricity rapidly displaces multi-blade turbine uses
Increasingly Significant Power Source Wind could generate 6% of nation’s electricity by 2020. Wind currently produces less than 1% of the nation’s power. Source: Energy Information Agency
Types of Wind Power • The major types of wind power are: • Utility-scale wind:wind turbines larger than 100 kilowatts are developed with electricity delivered to the power grid and distributed to the end user by electric utilities or power system operators; • Distributed or "small" wind: which uses turbines of 100 kilowatts or smaller to directly power a home, farm or small business as it primary use; • Offshore wind: which are wind turbines erected in bodies of water around the world, but not yet in the United States.
Mechanism • When wind blows past a turbine, the blades capture the energy and rotate. • This rotation triggers an internal shaft to spin, which is connected to a gearbox increasing the speed of rotation. • The gearboxis connect to a generator that ultimately produces electricity.
Construction & Equipment • Parts of a wind turbine: • Foundation • Tower • Nacelle • Rotor blade • Hub • Transformer (this is not a part of the Wind Turbine)
Tower and foundation • In order to guarantee the stability of a wind turbine a pile or flat foundation is used, depending on the consistency of the underlying ground. • The tower construction doesn’t just carry the weight of the nacelle and the rotor blades, but must also absorb the huge static loads caused by the varying power of the wind.
Rotor and rotor blades • The rotor is the component which, with the help of the rotor blades, converts the energy in the wind into rotary mechanical movement. • Currently, the three-blade, horizontal axis rotor dominates. • The rotor blades are mainly made of glass-fiber or carbon-fiber reinforced plastics (GRP, CFRP). • The blade profile is similar to that of an airplane wing. • They use the same principle of lift. (on the lower side of the wing the passing air generates higher pressure, while the upper side generates a pull. These forces cause the rotor to move forwards, i.e. to rotate.)
Nacelle • The nacelle holds all the turbine machinery. • Turbine machinery consists of gearbox, generator, coupling and brakes to the rotor. • It rotates to follow the wind direction. • It is connected to the tower via bearings.
Gearbox • The gearbox converts the rotor motion of 18-50 rpm into the approx. 1,500 rpm which the generator requires. • The gearbox thus takes on the task of matching the rotation speeds of the slow-moving rotor and the fast-moving generator, and generally has several steps to cover for various wind conditions.
Generator • For high power wind turbines, doubly-fed asynchronous generators are most frequently used. • The operating rotation speed can be varied somewhat, unlike when using conventional asynchronous generators. • Another concept uses synchronous generators. A grid connection of synchronous generators is only possible via transformers, due to the fixed rotation behavior. • The disadvantage of requiring complicated control systems is countered by the overall efficiency and better grid compatibility.
Coupling and brake • Because of the enormous torque, the coupling between the main shaft and the transmission is a rigid one. • The type of brake depends on the control mechanism for the blades.
Electronic equipment • These are composed of the generator, the system for the grid in feed of the electricity, and various sensors. • Sensors include: • Temperature Sensor • Wind Direction Sensor • Wind Speed Sensor • Fault Sensor in nacelle • Control and Monitoring
Other components • The wind turbine contains components for following the wind direction, for cooling, heating and lightning protection, as well as lifting gear (e.g. winches for spare parts) and fire extinguishing equipment.
Typical Wind Turbine Operation • 0-5 m/s Wind Speed is too low for generation power. Turbine is not operational. Rotor is locked. • 5-15 m/s 5 m/s is the minimum operational speed. It is called “Cut-in speed”. In 10-25 mph wind generated power increases with the wind speed. • 15-25 m/s typical wind turbines reach the rated power at wind speed of 15 m/s. • >25 m/s Turbine is shut down when speed is higher than 50 mph (called “Cut-Out” speed) to prevent structure failure
Wind Power Advantages • Environmental • Economic Development • Fuel Diversity & Conservation • Cost Stability
Environmental Benefits • No air pollution • No greenhouse gasses • Does not pollute water with mercury • No water needed for operations
Pollution from Electric Power Electric power is a primary source of industrial air pollution
Economic Development Benefits • Expanding Wind Power development brings jobs to rural communities • Increased tax revenue • Purchase of goods & services
Fuel Diversity Benefits • Domestic energy source • Inexhaustible supply • Small, dispersed design • reduces supply risk
Cost Stability Benefits • Flat-rate pricing • hedge against fuel price volatility risk • Wind electricity is inflation-proof
= 1/2 x air density x swept rotor area x (wind speed)3 A V3 Power in the Wind (W/m2) Density = P/(RxT) P - pressure (Pa) R - specific gas constant (287 J/kgK) T - air temperature (K) Area = r2 Instantaneous Speed (not mean speed) kg/m3 m2 m/s
Siting a Wind Farm • Winds • Minimum class 4 desired for utility-scale wind farm (>7 m/s at hub height) • Transmission • Distance, voltage excess capacity • Permit approval • Land-use compatibility • Public acceptance • Visual, noise, and bird impacts are biggest concern • Land area • Economies of scale in construction • Number of landowners
Wind Disadvantages • Siting • Avian • Noise • Aesthetics • Intermittent source of power • Transmission constraints • Operational characteristics different from conventional fuel sources • Financing
Wind Energy and the Grid • Pros • Small project size • Short/flexible development time • Dispatch ability • Cons • Generally remote location • Grid connectivity -- lack of transmission capability • Intermittent output • Only When the wind blows (night? Day?) • Low capacity factor • Predicting the wind -- we’re getting better
Birds - A Serious Obstacle • Birds of Prey (hawks, owls, golden eagles) in jeopardy • Altamont Pass – News Update – from Sept 22 • shut down all the turbines for at least two months each winter • eliminate the 100 most lethal turbines • Replace all before permits expire in 13 years
Wind Energy- The need of Pakistan • Now-a-days Pakistan is suffering from a great downfall of energy that is causing a great loss in all walks of life. • Now Pakistan need a permanent and reliable source of energy, i.e. THE WIND ENERGY • There are many sites in Pakistan that are compatible for installing the Wind Turbines. • In future, if Pakistan work on this permanent source of energy, In Sha ALLAH, we will overcome this shortfall of energy.