Wind PowerCUTTY SARK

Weibull DistributionWeibull Distribution Plotter Programme

Wind - simple physicsWind velocity = v: blade radius = RBlades sweep out area A = R2 Air density = Mass of air arriving per second = M = A v Its KE is M v2 = A v3 Want large swept area ie long bladesThe v3 factor is very favourable in high-wind regionsCold air is denser - better - implies higher towers

LECTURE NOTES BY PROFESSOR J L CAMPBELL University of Guelph

Weibull Distribution.Asymmetric high winds are less probable than lowBut high wind speed means much more power (v3)You CANNOT just substitute the average wind speed into the equation for power output of turbineYou must add up the power increments at each wind speed on the distributionThis typically doubles the calculated power output!

BUT if you somehow extracted all the kinetic energy, the air would stop dead after the rotors - no more air could arrive - not realistic!You can only extract some fraction less than 100% of the energy

Profile of air flowMass of cylinder of air arriving from right is M1 =v1 r12 Cylinder exiting at left has decreased velocity, so M2 = v2 r22 But obviously M1 and M2 are the sameTherefore r2 is larger than r1: the cylinder of air is wider downstream of the turbineThis helps determine spacing of wind farms

Efficiency calculation: Bettz lawWind approaches rotor, perpendicularly, at velocity v1Some energy is extracted, so velocity falls to v2Assume mean speed through actual rotor is the average ie vm = 0.5 (v1 + v2)Mass passing through per sec is m = vm A Power extracted = 0.5 m v12 - 0.5 m v22 = 0.5 vm A (v12 - v22 )P = 0.25 A (v1 + v2) (v12 - v22 )If there were no rotor, undisturbed power would be P0 = 0.5 A v13

Write v2/v1 = x Then ratio R = P/P0 = 0.5 (1 - x2 ) (1 + x) R is maximum when dR/dx = 0Do this. Find that x = 1/3, corresponding to R = 0.59So we get maximum efficiency of 59% at v2/v1 = 1/3 and Power P = 8 A v13 /27Issue of tower spacing in a wind farm1916

Wind speeds and location criteria

Wind speeds and location criteria..Average speed at Danish installations (ie most advanced country) is 6.3 m/sAverage SW winds on shores of Great Lakes are to 8 m/sIn USA there are 232,000 square kms of Class 4 land within 10 km of existing transmission facilities, ie 8 times more land than for Classes 5+6 combined. Effort must focus on Class 4 areas

Wind speeds:Mapping the resource

These figures are very similar to Germany, where installation is proceeding rapidly

Wind - environmental impactNo air pollutionElectromagnetic interference eliminated via non-metallic bladesBird-kills decreased by move from lattice to tubular towers - average is 2.2 birds per turbine per year - less than office towersMain accidents are falls Noise much decreased - almost none at 200 mCompatible with farming, recreation, forestryOnly 1-2% of land is actually occupied - can cultivate to within a few metres of a tower

Wind - installations 1

Cost issues

Canadian Wind Energy Association

Wind installations.2

Cost issues.AWEA/DOE cite USA wind generation cost as 3.9 5 cents(US) per kWh in 2002That is 5.3 6.8 cents CanadianCompare Ontario legislated price of 4.3 c, which is much less than true cost, and which is scheduled to rise

Costs are droppingBlades are lighter - towers can be higher: 50-90 m tubular towersLower O/M costs; higher reliability; 25-30 y lifetimeBigger turbines: half of new ones now exceed 1 MWeEarly 1980s cost C$0.55 per kWh2000 cost C$0.06 per kWhGeneral observation in technology: Costs decrease 20% when # of units produced doublesWorld capacity likely to double in 5 y

Design issues

Tower height is crucial: wind speed at 60 m height can be 20-60% greater than at ground levelHeavy cold air gives up to 15% more powerSite at end of large flat areas eg Great LakesSeek large blade areaMaterials must withstand shear stressesShould rotate to align with changing wind direction

Capacity FactorAnother way of stating the annual energy output from a wind turbine is to look at the capacity factor for the turbine in its particular location. By capacity factor we mean its actual annual energy output divided by the theoretical maximum output, if the machine were running at its rated (maximum) power during all of the 8766 hours of the year.

126 m diameter5 MW

Mapping the wind resource.Wind speed is only the first part of picture. It is power that matters, and what about direction?Wind rose concept see website of Danish Wind Power associationDivide a circle into 12 quadrants representing 12 measures of wind direction in 30 degree segments of the full 360 Give each a radius corresponding to the wind speed

Mapping the wind resource.Change to using velocity-cubed and make the radius of each quadrant proportional to the velocity-cubed from that direction plot in redAdjust so that the sum of these v3 values is 100%Now you are showing the power distribution around 360 degrees, both in direction and magnitudeData for a wind-rose must be averaged over several years eg from European Wind Atlas

Supply versus demand issueAnnual capacity factor 25-35%High winter winds plus cold dense air match maximum demand, especially for heating buildings68% of Ontario production would be in October - MarchHigh winter availability counteracts high costs of other sources BUT on still, humid summer day, wind is zero and air-conditioning demand is maximum

US Department of Energy

23. 04. 2009. | 18:29Obamin veliki zaokret prema izvorima energijeU SAD-u e svijetliti vjetar, plima i osekaAutorSergej upani

Ameriki predsjednik u vjetroelektrani u Iowi najavio smanjenje emisije CO2 83 posto do 2050, 20% do 2020.

Barack Obama pozvao je na Dan planeta Zemlje svoju naciju na poetak nove ere u uporabi energije, to bi unaprijedilo ouvanje okolia i potaknulo gospodarski razvoj te otvaranje novih radnih mjesta.

Published online 11 February 2009 | Nature 457, 775 (2009) News in BriefWind producers around the world installed more than 27 GW of capacity in 2008, bringing global capacity to nearly 121 gigawatts.

Integrating power into grid

Nominalna snaga: 5,6 MW (7 vjetrogeneratora od 850 kilowata)Realizirana snaga: 1.06 MW -> 19%1MW, 7M Eura -> 7Eura/W snage

Captain Moore left the ship in 1885, and was replaced by the most successful Master who ever commanded the Cutty Sark; Richard Woodget. Captain Woodgets skill lay as a successful man-manager and fearless navigator, getting the best out of both the ship and his crew. In order to catch the Roaring Forties trade winds, encountering some of the most violent gales and seas on Earth, Woodget would travel further south than any previous commander. This was perilous, as the ship came into frequent contact with icebergs around Cape Horn (the southern tip of South America). Woodget was also a keen photographer and he has left many striking images of the ship passing icebergs as well as shots of her in Sydney harbour.Fortunately, the ship survived and produced stunning passage times. On his first voyage in command, the ship sailed from England to Sydney in 77 days, and returned to the UK from Australia in 73 days. This was the start of 10 years domination by the Cutty Sark in the wool trade. http://www.windpower.org/en/tour/wres/weibull.htmhttp://www.windpower.org/en/tour/wres/weibull/index.htm?radio1=m&mean=7.0&k=2.5LECTURE NOTES BY PROFESSOR J L CAMPBELL, University of Guelph

www.physics.uoguelph.ca/~jlc/phys3080/EnergyP14.pdfhttp://en.wikipedia.org/wiki/Betz'_lawhttp://www.windpower.org/en/tour/wres/betz.htmGlobal_Wind_2007_Report_finalwww.canwea.cahttp://www.repower.de/index.php?id=369&L=1&det=1413 July 2007The second REpower 5M offshore wind turbine has just been installed successfully off Scotland east coast. The turbine which is located in a water depth of 45 metres and 87 metres above the mean sea level, just like the 5M installed in August 2006, is part of the eatrice Demonstrator offshore project which REpower and the British companies Talisman Energy Inc and Scottish & Southern Energy are engaged in. The wind farm established three records at once: For the first time, offshore wind turbines have been completely assembled onshore; second, never before wind turbines have been installed in such a water depth; and third, this is the most northern offshore wind farm in the world. The second turbine will be commissioned within a short time. With a total capacity of 10 megawatts, the wind farm will satisfy two-thirds of the energy demand of the neighbouring Talisman Energy oil platform. Especially the experiences in the 5M offshore operation will be of particular importance for REpower expertise. http://www.windpower.org/en/tour/wres/euromap.htmhttp://www.eere.energy.gov/windandhydro/windpoweringamerica/pdfs/wind_maps/us_windmap.pdfUS Department of EnergyHEPThe wind farm, which will consist of 88 turbines, is planned to start production in 2011. When fully operational, its annual electricity production is expected to be around 1.1TWh, enough energy to power around 220,000 UK homes. Total investments are estimated at approximately NOK 10 billion.Until now, the 315 MW Sheringham Shoal project has been owned 100% by StatoilHydro. Through an agreement, Statkraft will acquire 50% of the shares in the project, thus becoming an equal partner with StatoilHydro.Adria Wind PowerVjetrolektrana Ravne 1 ima nazivnu snagu 5,6 megawata koju daje 7 vjetrogeneratora, pojedinane snage 850 kilowata"Sedam vjetroelektrana s po 800 kW godinje e davati 15 milijuna kWh. U to je investirano 7 milijuna eura