Update on Over the Horizon Wireless Power Transmission (OTH-WPT) A Low-Cost Precursor for Laser Space Solar Power
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UpdateonOvertheHorizonWireless PowerTransmission(OTH-WPT) ALow-CostPrecursorforLaserSpaceSolarPower PaulJaffe,U.S.NavalResearchLaboratory TanwinChang,DeepPhaseLabs BertMurray,LighthouseDev ThisworkisdedicatedtothelateNewYorkInsOtuteof TechnologyProfessorStephenBlank Overview • • • • • • Mo8va8on LaserSSPConcepts LaserPowerBeamingDemonstra8ons WavelengthTrades SSPConceptswithHigh-Al8tudeElements ProposedTerrestrialDemonstra8on Demonstra8onMo8va8on • ThehighcostofgeDngtospacehasbeenan obstacletodemonstra8onimplementa8ons • OvertheHorizonWirelessPowerTransmission,OTHWPT,isproposedasalowcostprecursortoSSPthat doesnotrequireaccesstospace “...large-scaledemonstra8onofpowerbeamingisa necessarysteptothedevelopment ofsolarpowersatellites.” –GeoffreyLandis,scien8standauthor SelectedLaserSSPConcepts EADSAstriumConcept,circa2010 Tetheredaerostatcouldbeusedinsteadof microwavebeamfromhighal8tudeplaUorm(HAP) Two-stageSSPConcept JAXAConcept,circa2011 SelectedLaserPowerBeaming Demonstra8ons EADSAstriumtrackinglasertopowerrover,circa2003 KinkiUniv.&HamamatsuPhotonicsInc.laserpowerto smallhelicopter,circa2007 LighthouseDevEye-safelaserdemoh`p://www.bbc.co.uk/programmes/p00yjt995:40,circa2012 Lasermo8veoutdoorlaserpowertoUAV,circa2012 ComparisonofMicrowaveandLaser PowerTransmissionforSSPfromGEO Microwave Laser Transmitfrequency 5.8GHz 1.4mm TransmitApertureDiameterInGEO 1km 2.5m ReceivingApertureDiameterOnor NearEarth 3.2kmonearth 40m DemonstratedTransmi`er ConversionEfficiency ~80% ~30% DemonstratedReceiverConversion Efficiency ~90% ~50% VulnerabilitytoWeather Probablynegligible Notnegligible* SpectrumAlloca8onChallenges Likelytobehigh ? Interna8onalPoli8calChallenges ? Likelytobehigh* *thisproblemmaybereducedoreliminatedbyusingahighal8tudereceivingplaUorm LaserSourcesatTenvs.Onemicron 10.6microns 1064nm Transmitfrequency ~30THz ~300THz LaserTechnology CO2SealedGas Laser DiodePumpedFiber Laser Costperwa`(COTs) <$100perWa` ~$100perWa` DemonstratedTransmi`er ConversionEfficiency >20% >30% DemonstratedReceiverConversion Efficiency TBD ~50% SWaP(turn-keysystem) <10kg/100W <5Kg/100W LaserSafetyChallenges “EyeSafe” Corneaistransparent SpacetoTetheredAerostatSSP • Beamingfromspacetoahighal8tudetethered aerostatavoidsmaineffectsofatmospheric a`enua8on • Poten8allyallowsuseof“eye-safe”lasertransmit frequencywhichresultsinfarsmalleraperturesvs. microwavefor:transmitantennainGEOandreceive apertureontheaerostat WhatisProposed? • LongRangeWirelessPowerBeamingusinga ground-basedhigh-powerlaserandahigh-al8tude receivingplaUorm • 100sofkmrange • Deliveryof100sofkWelectricpower • Manyotherconfigura8onsarepossibletomeet varietyofrange,power,weatherandtac8cal needs • Perhapsleverageexis8ng“directedenergy”assets Demonstra8onConfigura8on OTH-WPTGoal&Conclusion • Providedeployable,portable,longrange, economicalpowertransmissionforcivil, commercial,andsecurityapplica8ons • OvertheHorizonWirelessPower Transmissionrepresentsanachievable,lowcostprecursorforSpaceSolarPower ThankYou Paul.Jaffe@nrl.navy.mil OTH-WPTFunc8onalBlockDiagram (do`ed indicates op8onal element) LaserPowerConverter Aerostator HighVoltage Panel Power Airborne Trihedral PlaUorm ReflectorPanel Conversion PilotSignal Beam Path Wavefront Sensor Power Supply Control Electronics Adap8ve Laser Op8cs GroundLoca8on1 Tether Steering Mirror Power Condi8oning &Distribu8on GroundLoca8on2 Frequency/WavelengthComparisonforaTerrestrialWPTLink with10mApertures&100kmRange 2.45GHz 5.8GHz 34GHz 94GHz 1.0μm Eff.Rx 1.5μm “eyesafe” 90.6%† 82.7%† ~70%† ~37%† 44.7% 44.7%iii Eff.Tx 62%ξ 82%iv 73% 25% 53%i 64% Atmospheric A`enua8on Negligible Negligible Negligible Negligible >50%ii <10%ii 1mW/cm2 1mW/cm2 1mW/cm2 Possible FAAissue Possible FAAissues Safepower 1mW/cm2 v densitylimit Regulatory challenges Wifi Bluetooth Minimal 0.09W/cm2 0.08W/cm2 Yes Total Efficiencyat 1% 4% 16% 6% 23.7% 100km* *withatransmi`erradiusof10mandareceiverradiusof10m,100kmrange ReceiverEfficiencies:Durgin;Valenta(2014)Harves(ngWirelessPower Green=Be`er ξh4p://www.microwavejournal.com/ar(cles/9441-a-compact-high-power-2-45-ghz-microwave-generator χAssumingaGaussianDistribu8on,10dB,and21receiverelements Yellow=Okay iMcCormicSchoolofEngineeringandAppliedScience iih`p://people.bu.edu/clemens/mimir/atmospheric_transmission.html Red=Worse iiiDimroth,F,WaferBondedfourjunc(onGaInP/GaAs//GaInAsP/GaInAsconcentratorsolarcellswith44.7%efficiency,Progressin Yes 28.6% † Photovoltaics(2014) IvMcSpadden,James,DesignandExperimentsofaHigh-Conversion-Efficiency5.8GHzRectenna(1998) vICNIRP."OnLimitsofExposuretoIncoherentVisibleandInfraredRadia8on."2013.Report. Adaptedfroma chartcreatedby MickeyDaSilva forDHS Rangeasafunc8onofairplaUormheight,(km), (atmospherica`enua8oneffectsnotincluded) 300 r ( h) 200 100 0 2 4 6 h 8 10 Es8matedTransmissioncoeff.,T(L,h),atλ=1.06μm asafunc8onofairplaUormheight(hkm)and horizontalbeamingdistance(Lkm) Demonstra8onConfigura8on • Advantages: • Atmospherica`enua8onone direc8ononly • Powereasilysenttomul8ple loca8ons • Disadvantages: • Requirestether • Poten8alradia8onhazard Converter Panels Power Down Tether Notes: Airshipal8tudesabove troposphere Transmi`er AirborneReflectorConfigura8on • Disadvantages: • Atmospherica`enua8onbothdirec8ons • Poten8alradia8onhazard • Advantages: • Oneairship • Notethers Reflector Note: Tethercouldbeused withairshipifdesired. Transmi`er Converter Panels AirborneReflectorConfigura8on • Advantages: • Oneairship • Notethers/powercables • Disadvantages: • Atmospherica`enua8onbothdirec8ons • Poten8allaserradia8onhazard PowerBeamDownConfigura8on • Advantages: • Atmospherica`enua8onone direc8ononly • Powereasilysenttomul8ple loca8ons • Easierlogis8csatreceivingsite • Disadvantages: • Requirestether • Poten8alradia8onhazard Transmi`er Power Up Tether Converter Panels BeamatAl8tudeConfigura8on • Advantages: • Minimizesatmospherica`enua8on • Verylongrange,poten8ally>1000km • Powereasilysenttomul8pleloca8ons Converter Panels Power Down Tether Notes: Airshipal8tudesabove troposphere • Disadvantages: • Twoairships • Requirestethers Transmi`er Power Up Tether BeamatAl8tudeConfigura8on • Advantages: • • • • Minimizesatmospherica`enua8on Verylongrange,poten8ally>1000km Powereasilysenttomul8pleloca8ons Li`leornoradia8onhazard • Disadvantages: • Twoairships • Requirestethers/powercables DesignChallenges • Airborne/fielddeployablehighpowerlasers • Beampoin8ng,tracking,retro-direc8vity • Compensa8ngforatmosphericeffects • Mirrorsforhighpowerlasers • Laserpowerconversion • Laserradia8onsafety • AirplaUorm:highal8tude,longdura8on* • Tether:lightweight,lowresistance,highvoltage • Airtrafficcontrol *Aerostatscurrentlyoperateat4-5kmwithupto90 mphwindsurvivability. HardwareSources • Highpowerlasers: – IPGPhotonics – Teradiode • BeamControl: – LighthouseDevelopment – Adap8veOp8cs/NorthropGrumman – Boeing – Lasermo8ve • Aerostats: – ILCDover – T-com • Laserenergyconversion: – Spectrolab – JXCrystals Radia8onSafety • • • • Interlockingintrusioncontrol Beampoin8ngposi8vecontrol Powerdensitylimita8ons Wavelengthchoicetominimizepoten8al radia8onhazardtopersonnel,animalsand equipment,(1.5mmorlonger,eye-safe) TechnicalIssues • Theamountoflossalongthetetherduring thetransmissionoftheelectricalpowerto thegroundisanimportanttechnicalissue. • Thislosscanbereducedthroughtheuseofa lowresis8vityconductorandthechoiceofa highvoltagefortransmission. TechnicalIssues • Cloudscanoccuratopera8onalal8tudes. • Sta8s8calanalysisofmeteorologicaldatashowthat theprobabilityofoccurrencedecreaseswith al8tudeandisnotsta8callysignificantatal8tudes above6km. • ref:i)ChilboltonObservatory,UK ii)Cloudnet,2007,h`p://www.cloud-net.org/ St:stratus,Sc:stratocumulus,Nb:nimbostratus;Ac:altocumulus,As:altostratus;Ci: cirrus,Cs:cirrostratus,Cc:cirrocumulus;Cu:cumulus,Cb:cumulonimbus. DensityofAirvs.Al8tude h`p:// www.aerospaceweb.or g/ques8on/ atmosphere/ q0046b.shtml 1.6 1.4 AtmosphericDensity 1.2 1 0.8 0.6 0.4 0.2 0 AlOtude h`p://www.braeunig.us/space/atmos.htm LighterThanAir(LTA) Aerostats HeavyLid HighAlOtude Airships ABCA60 56K ISIS 4.2MTowTech PTDS74K HALE-D SkyTug Zeppelin TARS420K MA-3 HAA Star²Tower LEMV GNSS40Kto80K Lightship TetheredAerostatwithgroundsta8on Tetherproper8es Aerostats,widelyused,U.S.mfg.items. AirPlaUormTechnicalIssues • Strongwindsandlightningatopera8onal al8tudesandpossibleinterferenceofthe aerostatwithavia8on. • Theseproblemsarecommontootherhigh al8tudeaerostatsusedforsurveillance purposes,whichsurvive90mphwinds,have lightningprotec8onandcarrywarning systemstoavoidcollisionwithairtraffic. • Poweredstabiliza8onwillbestudied. OTH-WPTPortability • OTH-WPTwouldbehighlyportableandrela8vely economical • Aerostatandgroundsystemcouldbemoved withrela8veease • Portabilityofgreatimportanceinproviding powertoremoteareasonanemergencybasis andtotheatersofopera8onthatarerapidly changing • Hard-wiredpowerlinesorfueltruckingareo€en notfeasibleorareveryexpensivetoremote areas FutureMaterial • Historicallyrelevantwork: – Fischer – AFRLDirectedEnergydemotocranesuspendedmirror • Graphicalrangecomparisonshowingadvantageof aerostatovertower – Geometricadvantage – Reducedatmospherica`enua8onadvantage • ActualFOBexamplecase,AFG? • Fully-burdenedcostoffuelvs.lasereffetc. • Powerdensity&receiverareaexplana8on Electromagne8cWaves High Frequencies Blocked h`p://www.rfcafe.com/references/electrical/ew-radar-handbook/images/imgh51.gif Low Frequencies Admitted 10.6MicronConversionOp8ons • Usefulphotovoltaicsdonotexistat10.6 micronsduetotheinefficiencyofgenera8ng powerfromasmallband-gapmaterial • Heatenginesareapoten8alsolu8on,butnot idealat10.6micronsduetotherela8vely largespotsizeofthetransmi`edbeam • Microscopicantennaswithdioderec8fica8on: Rectennas,or“Nantennas” Nantennas • Combina8onofalithographicallyproduced bow8eantennawithgeometric(ballis8c)diode Anode Cathode Bowtie Antenna Graphene GeometricDiode Depic8onadaptedfromJoshi,S.;ZixuZhu;Grover,S.;Moddel,G.,"Infraredop8calresponseofgeometricdioderectennasolarcells," PhotovoltaicSpecialistsConference(PVSC),201238thIEEE,vol.,no.,pp.002976,002978,3-8June2012 WPTConsidera8onsforMostContexts • TradeoffbetweenTx/Rxareaandpower densitydependingonsafetyrequirements, availablecollec8onarea • Factorsaffec8ngavailability:atmospheric condi8ons,sourcereliability,suscep8bilityto single-pointfailures • Regulatory,safety,andincumbentuserissues • Cost&u8lityvs.alterna8ves WPTModality:Space-to-Space • Applica8ons – Frac8onatespacecra€ – Enablepowerforveryloworbitorlow-profilespacecra€ • Notes – Musthavecompellingadvantageoverwidelyavailable 1400W/m2sunlight,suchasminimizingdrag – Couldmake“safe/hold”modechallengingifnoba`eryor PVbackup – Poten8allaseradvantagesincenoatmospheric a`enua8onandminimaleyesafetyconcerns WPTModality:Space-to-air/sea/ground • Applica8ons – Classicspacesolarpowerapplica8ons – Disasterresponsepower – Spacelaunch – Seeapplica8onsfromNRLSBSPreportnextslide • Notes – Abilitytosendpowertoloca8onswithinahuge globalareamaypresentacompellingadvantage – Powerwouldbequicklyredirectablewithoutgrid lossesorextantinfrastructure – Economiccasechallengingtomake Outline FromNRL SBSPreport, prospec8ve, militarypower beamingscenarios WPTModality:Ground-to-air/space • Applica8ons – UAVdwellextension/poweraugmenta8on – Elementofdisasterresponse/ba`lefieldpower transmissionnetwork – Spacelaunch – Enablepowerforveryloworbitspacecra€ • Notes – ExtendedUAVopera8onswithoutpowerbeaming alreadydemonstrated WPTModality:Sea/ground-to-sea/ground • Applica8ons – Shiptoshorepowerbeaming,viceversa – Powerforsensorsindeniedareas – Powerto/from/betweenFOBs/COPswithtowers oraerostats • Notes – Poten8altousebeamexpansionwithexis8ng directedenergyassetstoreducepowerdensity to“safe”levels Backup NRLSBSPStudyGroupSummaryFindings • Finding3,MilitaryoperaOonsscenarios: – SBSPsystemsemployingmicrowavepowertransmissionat frequenciesbelow10GHzaremostsuitedforalimitednumberof basesandinstalla8onswherethelargearearequiredforefficient powerrecep8onwouldbeavailable. – Forapplica8onsrequiringsmallerapertures,millimeterwaveorlaser powertransmissionmaybepreferable,thoughtradeoffsbetween safety,increasedatmospherica`enua8on,andreceivedpower densitymustbeaddressedcarefully. – Directpowertransmissiontoindividualendusers,vehiclesorvery small,widelysca`erednodesdoesnotcurrentlyappearprac8cal, primarilybecauseofthelargeinefficienciesandthepossiblerisksof providingwhatamountstoa“naturalresource”. – Backupalterna8vesshouldbeconsideredforinstalla8onsintheevent offailure,compromise,ormilitaryac8onasanSBSPsystemmay presenttheproblemofasinglepointoffailure. 2008-09-30 SBSP47 Finding3,SBSPMilitaryOpera8onsScenarios BackgroundChart(1of2) • ForwardOpera8ngBasePower – Possible,butlikelyonlyapplicabletofairlylargeinstalla8ons. • Bista8cradarilluminator – Possible. • Providepowertoaremoteloca8onforsynthfuelproduc8on – Possible,butrequiresconsiderableinfrastructure,feedstock,andforcesthat couldexploittheproducts. • Powerfordistributedsensornetwork – Unlikely.Powerdensi8es,inefficienciesofwidespreadisolatedreceivers,and possibleenemyexploita8onof“naturalresource”areproblema8c. • PowertoIndividualEndUsers – Unlikely.Similarproblemstotheabove,withtheaddedconcernsofextreme precisionbeamcontrolandpossiblyunsafepowerdensi8es. 2008-09-30 SBSP48 Finding3,SBSPMilitaryOpera8onsScenarios BackgroundChart(2of2) • Spacesolarpowertonon-terrestrialtargets – Satellitetosatellitepowertransmission • Possible,butposessignificantsystemdesignproblems,andmaynot comparefavorablytodirectpowercollec8on. – SpacetoUAVfordwellextension • Small,movingtargetchallengeswirelesspowerbeamcontrol;mul8-day solarUAVflightsmayrenderthisapplica8onirrelevant. • TerrestrialWirelessPowerBeamingApplica8onsApartfrom SBSP – Shiptoshorepowerbeaming • Possible,requiresrefinementofwirelesspowerbeamingtechnologies. – GroundtoUAVfordwellextension • Sameissuesas“SpacetoUAV” 2008-09-30 SBSP49 NRLSBSPStudy–RevisitEfficacyof SBSP RecommendaOonsfrom“Space-BasedSolarPower AsanOpportunityforStrategicSecurity”, NaOonalSpaceSecurityOfficePhase0Report(Oct2007) RecommendaOon#1:TheU.S.Governmentshouldorganizeeffec8velytoallowforthe developmentofSBSPandconcludeanalysestoresolveremainingunknowns. RecommendaOon#2:U.S.Governmentshouldre8reamajorpor8onofthetechnicalrisk forbusinessdevelopment. RecommendaOon#3:TheU.S.Governmentshouldcreateafacilita8ngpolicy, regulatory,andlegalenvironmentforthedevelopmentofSBSP. RecommendaOon#4:TheU.S.Governmentshouldbecomeanearlydemonstrator/ adopter/customerofSBSPandincen8vizeitsdevelopment. (AreasofpossibleNRLcontribuOon) 2008-09-30 SBSP50 TerrestrialPowerBeaming • Sendingenergywirelesslymayofferu8lityformilitary,disaster recovery,orgrid-infrastructuredeficientareas • Laserandmm-waveallowsmallertransmitandreceive aperturesvs.microwave • Safetyandcostarekeyconsidera8ons • UsinganaerostatorotherairborneplaUormforthepower transmi`erorreceivercangreatlyenhancetherange • Successfulterrestrialpowerbeamingcouldpavethewayfor spacesolarpower EscapeDynamicsmm-wavePower BeamingforSpaceLaunch • Buildingtheirowngyrotrons • DemonstratedhigherthanchemicalIspinJuly 2015 SLIDECONTENTFROMBERTMURRAY&ROBERTWINDSOR,LIGHTHOUSEDEV Eye-SafeLaserPowerBeamingDemoat theUniversityofMaryland • Thiseffortdemonstratedtheabilitytoremotelypowerdevicesusingan (unaided)eye-safelaserbeam • Rangeofdemonstra8onwasmuchshorterthanpossible – Demonstratedrangeof240meters – Rangeofupto2kmwouldhavebeenfeasible • Thistechnologyoffersuniquecapabili8esnotfoundelsewhereinindustry: – 10008messmallerareahazardzoneforhigh-powerapplica8ons – 308mesmorepowerthanmostcompe8ngeye-safesystems – FAAcompliant(nospecialpermitsneeded)fornominaleye-safebeams(nottrue ofsomecompe8ngtechnologies) • Thereisas8gmathatlaserpowerbeamingisterriblydangerousandexo8c– wewanttochangethat! • Thefactisthatthistechnologyissafeandactuallycostslessthanalterna8ve powermanagementschemesforsomeapplica8ons – Suchasremotecontrolledvehiclesforuna`endedsensors 06October2013 Acollabora8onbetweenLighthouse,LLC andEritek,Inc. SLIDECONTENTFROMBERTMURRAY&ROBERTWINDSOR,LIGHTHOUSEDEV ComponentsoftheDemo Receiver: Transmi`er: • FresnelConcentrator • GaSbPhotovoltaic • 10Wa`s@1550nm – Powercanbehigher • Withsafetywear,training – 125mmaperture • BeamDivergencelessthan100urad – Canbefocused • Bore-sightedwithvisiblelaser – 633nm,5mW – 50mmbeamdiameter – Usedtoassistaiming • Rifle-scopeviewingaid – Assistspoin8ngduringdaylight condi8ons 06October2013 – 0.35Vpercell – 6inseries – Max1.5wa`soutput • Voltagecondi8oners – Convertvoltage,current – Supply3.3V • PoweredEquipment – Bright-whiteLED – TransistorRadio – Smallmotor • Rawoutputcanchargesingle-cell ba`eries Acollabora8onbetweenLighthouse,LLC andEritek,Inc. ThankYou • PaulJaffe,NRL,paul.jaffe@nrl.navy.mil • TanwinChang,DeepPhaseLabs, tanwin.chang@deepphase.com • BertMurray,LighthouseDevelopment, hcm1955@gmail.com
