22/09/2014School of MarineNewcastleJniversityScience&TechnologyTidal EnergyVisit to Wuhan University of TechnologyDr Rose NormanSeptember2014www.ncl.ac.uk/marineSchoolofMarineNewcastleScience&TechnologyUniversityAContentsOriginof tidal energy：Tidalenergyconversionprocesses：Tidalresource.Tidalbarragesandlagoons。Tidal currentturbinesEnvironmental impact.Summaryann1
22/09/2014 1 Tidal Energy Visit to Wuhan University of Technology Dr Rose Norman September 2014 Contents • Origin of tidal energy • Tidal energy conversion processes • Tidal resource • Tidal barrages and lagoons • Tidal current turbines • Environmental impact • Summary
22/09/2014Schoolof MarineNewcastleScience&TechnologyUniversittNew.MoonSolar TideEarnOrigin of TidaliunSprng TideMoon福Energy?Earthrotatesabout polarFicstQuateCaxisonceevery24hoursNeap TideEarthrotatesaboutSunonceevery365daysMoon rotates about its ownaxisonceevery29.5daysFullMognMoonrotatesaboutEarthSpring Tideonceevery29daysSo Sun, Moon and EarthThird.Ouartetalignedonce every14.5Neap TidedaysEffectofmoon=2.15timesthat of sunCwww.ncl.ac.uk/marineSchoolofMarineNewcastleScience&TechnologyniversitTidal Energy Conversion Process-BarragesAveragepowerperArea,Atide for ebb-onlygeneration:BarrageHigh Tide LevepAR'gPRange,R2TT=tidal periodLowTideLevelp=densityofseawaterTurbineg=accelerationduetogravityCmann2
22/09/2014 2 Origin of Tidal Energy • Earth rotates about polar axis once every 24 hours • Earth rotates about Sun once every 365 days • Moon rotates about its own axis once every 29.5 days • Moon rotates about Earth once every 29 days • So Sun, Moon and Earth aligned once every 14.5 days • Effect of moon ≈ 2.15 times that of sun Tidal Energy Conversion Process - Barrages Range, R Area, A Low Tide Level High Tide Level Barrage Turbine Average power per tide for ebb-only generation: 2T AR g P 2 T T = tidal period ρ = density of seawater g = acceleration due to gravity
22/09/2014School of MarineNewcastleScience&TechnologyUniversityTidal Energy Conversion Process-CurrentPowerproduced perturbine:pAu'cP=-A=turbinesweptareap=densityofseawateru=velocity ofwaterC,=power coefficientwww.ncl.ac.uk/marineSchoolofMarineNewcastleScience&TechnologyOniversitTidal Resource-Tidal Range3DV920609m57GW(ap)a29GW30n6GW50HLLongifude ( deg)man3
22/09/2014 3 Tidal Energy Conversion Process - Current Power produced per turbine: p 3 Au C 2 1 P A = turbine swept area ρ = density of seawater u = velocity of water Cp = power coefficient Tidal Resource – Tidal Range
22/09/2014SchoolofMarineewcastleScience&TechnologyUniversinTidal Resource-Tidal CurrentHighPotential Areas forTidal ResourcesPentlandFirthandOrkneyWatersRound1DevelopmentSitesmaatSTieaw7Base MaSintegieArelUntedKingdotMaRSHECROWNPESTATEA
22/09/2014 4 Tidal Resource – Tidal Current
22/09/2014School of MarineNewcastleScience&TechnologyUniversityTidal BarragesSluiceGateWaterMarGenerationofelectricityBarragefromtidesisverysimilartoBasinhydroelectricgenerationexceptthatwaterisabletoflowinbothdirectionsLowWatMarkTurbineSimplestgeneratingsystemEstuaryFloorfortidalplantsisebbgenerating,involves adamorbarrageacrossanestuary.Sluicegates on the barrageallowthetidalbasintofillontheincominghightidesandtoexit through theturbinesystemontheoutgoingtidewww.ncl.ac.uk/marineNewcastleSchoolofMarineUniversityScience&TechnologyTidal Barrages95LeveBasinananeMSerLeveanoawodTime of DayTime of DayEbbGenerationFloodGenerationRVTwoWayGenerationTime of Daywww.ncl.ac.uk/marine5
22/09/2014 5 Tidal Barrages • Generation of electricity from tides is very similar to hydroelectric generation, except that water is able to flow in both directions. • Simplest generating system for tidal plants is ebb generating, involves a dam or barrage across an estuary. • Sluice gates on the barrage allow the tidal basin to fill on the incoming high tides and to exit through the turbine system on the outgoing tide Tidal Barrages Ebb Generation Flood Generation Two Way Generation