Wind Energy - University Of Cincinnati

Wind EnergyRam DaroliaRetired EngineerRam.Darolia@gmail.com11/4/19

References1. 20% Wind Energy by 2030 Increasing Wind Energy’sContribution to U.S. Electricity Supplywww.nrel.gov/docs/./41869.pdfNational Renewable Energy Laboratory2. Wikipedia

Don Quixote thought wind mills wereMonsters, Giants and DevilsCivic duty to kill themDon Quixote and his loyal servant Sancho Panza

Population Growth RateEducationAffluenceFarming to industrial ageGov. controlSocial pressure

Growth in energy consumption

New Delhi, November 2, 2019

Wind energy is to supplement other modesof power generation Clean and renewable/sustainable Never run out of windProduction of wind energy does not result in any form of solid, liquid, orgaseous emissions or residues: no CO2 or toxic fumes are emitted It does not deplete any form of fuel Once installed, it is easy and inexpensive to maintain Offshore installations becoming popular

Wind is a form of solar energy. Winds are caused by the unevenheating of the atmosphere by the sun, the irregularities of the earth'ssurface, and rotation of the earth. Wind flow patterns are modified bythe earth's terrain, bodies of water, and vegetationWind is formed when hot surface heat the air making it to rise. Thecooler air moves into empty space creating windLand heats up faster than water

10X GrowthEstimate22 percent of world’s electricity generation by windpower in two decades (Global Wind Energy Council)

Twenty eight percent of all new powergeneration built in the United States since2009 has come from wind

How many have seen/driven by a wind turbine?How can you get electricity from slow rotating blades?

How can you getelectricity from slowrotating blades?

How a wind turbine worksBasic parts:Blades (B) and Rotor (A) which rotate when the wind blowsShaft (C)Gearbox (D) to adjust for the speed of the windGenerator (G), which generates the electricityThe dynamo works by rotating a permanent magnet inside a coil of copper wire.The magnet causes the electrons inside the wire move in a particular direction. Atthe end of the coil are wires which carry electrons to provide electrical energy

An automatic yaw mechanism is provided to ensure thatthe rotor always faces the wind direction

RequirementsStiffnessBending stresses (wind load andgravity)Fatigue life: vibration and windvariationLightweight (fiberglass composites)

Blades are made of fiber-reinforced plasticsGRP glass-fiber-reinforced plastic, CRP carbon fiber reinforced plasticBlades must be stiff, and placed far enough ahead of the tower, to preventcollision with the tower under maximum wind conditionsThree-blade designs are by far the most commonBecause the wind speed increases and the wind flow stabilizes andbecomes less turbulent with height from the ground, towers as high aspossibleOffshore sites offer very high winds and large areas for utilization, oftenhaving more limited local environmental impactsCorrosive marine environment impose additional requirements

Rotor blade weight versus length

Wind turbines convert the kinetic energy in the wind intomechanical power. A generator converts the mechanicalpower into electricityLong bladesCan be two football field longHigh Tower to capture more windTowers made of steel

Size of large wind turbinesEnercon, Germany E-126Can generate up to 7 MW of electricity500 homesRotor diameter of 413 feetHeight 650 feetTotal weight 6000 tonIt only turns at 12 rpm. That means it takesfive seconds to complete one revolution10 to100 turbines in a wind farmVestas, Denmark V164,8 MW, rotor diameter, 538 ftFootball field is 360 feet long

Worlds largest turbines1. MHI Vestas V164-9.5MWPower rating: 9.5MWRotor diameter: 164m 540 feetBlade weight 35 ton, Tower height 613 feet2. Siemens Gamesa SG 8.0-167 DDPower rating 8MWRotor diameter 167m 548 feetLength of a football field 360 feet

Wind power potential in USA

Wind energy is the kinetic energy of air in motion, also called wind. Total windenergy flowing through an imaginary surface with area A during the time t is:[32]where ρ is the density of air; v is the wind speed; Avt is the volume of airpassing through A (which is considered perpendicular to the direction of thewind); Avtρ is therefore the mass m passing through "A". ½ ρv2 is the kineticenergy of the moving air per unit volume.Power is energy per unit time, so the wind power incident on A (e.g. equal to therotor area of a wind turbine) is:[32]

The Betz Limit59% of the energy11 miles/hour 31 miles/hourGentle breeze: 6-10 miles/hourLeaves and small twigs in constant motion,wind extends light flag.Moderate breeze: 10 to 16 miles/hourWind raises dust and paper, moves smallbranches.Wind energy content is proportional tothe cube of its speed.Energy generation typically does not cutin until wind is blowing at speeds of atleast 3 m/s to 5 m/s.High wind speeds cause high rotationspeeds and high stresses in the windturbine which can result in serious damageto the installation. Wind turbines areusually designed to cut out at wind speedsof around 14 m/s either by braking orfeathering the rotor blades allowing thewind to spill over the blades.Because of the upper speed limit at whichthe wind turbine can safely be used, it maycapture only half or less of the availablewind energy.

What is the minimum wind speed to turn theblades of a wind turbine?Latest models can start at about 5 miles per hour wind speed, but moststart at around 8 miles per hour,Turbines also need a electrical 'kick-start' from the National Grid to getthem into action, and a large amount of power is also required to brakethem when the wind speed hits around 50-55 miles per hour, which istheir upper safety limit.Wind energy council estimate (1994):27% of land surface has wind speed greater than 11miles/hourOnly 4% might be suitable due to unsuitable terrain, urban areas, cropcultivation, and other land uses

Largest wind farms20 GW Jiuquan Wind Power Base. Goal 200GW of installed wind capacity in the country1,600MW Jaisalmer Wind Park, India1,548MW Alta Wind Energy Centre (AWEC) in Tehachapi, Kern County, California1,500MW Muppandal Wind Farm, India845MW Shepherds Flat Wind Farm near Arlington in Eastern OregonLondon Array Offshore Wind Farm, UKThe London Array Offshore Wind Farm, the largest offshore wind farm in the world with an installedcapacity of 630MW, ranks as the world’s sixth largest wind farm. It is located in the outer ThamesEstuary more than 20km off the coasts of Kent and Essex.

Energy Storage with a Battery

A gigawatt can power about 800,000 householdsSouthern California Edison and San Diego Gas &Electric claims supply from batteries nowcompetes against natural-gas fired plantsBloombergBusiness, October 19, 2015

Molten salt is circulated through highly specialized piping in the receiver (heatexchanger) during the day, and held in storage tanks at night – requiring nofossil fuels The tanks store the salt at atmospheric pressure Use of molten salt for both heat transfer and thermal energy storage minimizesnumber of storage tanks and salt volumes needed Molten salt is stored at 1050⁰F (566⁰C) until electricity is needed – day or night,whether or not the sun is shining As electricity is needed, molten salt is dispatched from the hot tank through aheat exchanger to create super-heated steam which then powers a conventionalsteam turbine The molten salt never needs replacing or topping up for the entire 30 year lifeof the plant Heat loss is only 1⁰F per day The salt, an environmentally friendly mixture of sodium nitrate and potassiumnitrate, is able to be utilized as high grade fertilizer when the plant is eventuallydecommissioned

Molten salt is stored at 1050⁰F until electricity is needed –day or night, whether or not the sun is shining

World's Largest Offshore Wind FarmsGE to provide world's mostpowerful turbines for British windproject: capacity of 12 megawatts(MW)October 1, 2019

Status unknown: numerous challenges and barriersBuilt by Trans-Elect and sponsored by GoodEnergies, Google, Marubeni Corporation andElia System OperatorThe Mid-Atlantic region offers more than 60,000 MW ofoffshore wind potential in the relatively shallow watersof the outer continental shelf. These shallow waters,which extend miles out to sea, allow for thedevelopment of large, distant wind farms, mitigatingvisibility issues and allowing for greater energy capturefrom stronger winds.7,000 MW of offshore wind, enough power toserve approximately 1.9 million households.Initial cost; 1.3 billionGoogle commitment: 5 B133,000 and 212,000 U.S. Jobs during construction43,000 permanent operations and maintenance jobs would be created if 54,000 MW ofoffshore wind turbines were installed by 2030.

Countries Depending on Wind PowerWind can provide 40 times current worldwideconsumption of electricity, 5 times total globaluse of energy in all forms

New industry guidelines, aim to save tens of thousands ofbats each year by idling turbines at low wind speedsduring peak bat migration season. They could reduce bya third the number of bats killed at wind farmsMigratory bats, for some reason, have a lethal attractionto wind turbines. Now, they may get help via "feathering.“By Andrew Curry, for National GeographicPUBLISHED SEPTEMBER 02, 2015

North America’s largest bird, Candor: nine-and-a-halffoot wingspan bird of uncommon intelligence andlongevity. manipulates hot winds to soar hundreds ofmiles without flapping its wings.With the investment of tens of millions of dollars andextraordinary effort by scientists, the condor, is staginga spectacular comeback after verging on extinction 25years ago. The 200 birds in the wild today (out of 400total) are rapidly expanding their historic rangeIt’s a flight path that is taking the condor perilouslycloser to the spinning blades of Tehachapi windturbines that depend on those same thermal currentsto generate power; biologists fear it’s only a matter oftime before the condor begins hitting the 500-foot-highmachines.A single death could be catastrophic for the windindustry, the regional economy and, not least, thecondor. “We cannot envision a situation where wewould permit the lethal take of California condors. Theday a condor is killed by a wind turbine in Californiachanges the course of future development.”Deploying avian radar units that could shutdown turbines when a condor approachesappears to be getting the most attention

Revival Of Iconic California Condor Threatens State'sWind Farm BoomForbes, 1/16/2012In the past 36 months the wind industry has attracted 3.2 billion ininvestment to the Kern County, region, California (Tehachapi Mountains)A multibillion-dollar transmission line under construction in the Tehachapiwill carry as much as 4,500 megawatts of renewable energy, most of it fromwind farms, to coastal cities.At peak output that’s the equivalent of four or five big nuclear power plantsand a linchpin of California’s mandate to obtain a third of its electricity fromrenewable sources by 2020.

Wind energy is the kinetic energy of air in motion, also called wind. Total wind energy flowing through an imaginary surface with area A during the time t is: . The London Array Offshore Wind Farm, the largest offshore wind farm in the world with an installed capacity of 630MW, ranks as the world's sixth largest wind farm. .