Ocean Thermal Energy Conversion (OTEC) : Methods & Benefits.

Topic: Ocean Thermal Energy Conversion (OTEC)

Overview:
The presentation introduces OTEC, a renewable energy technology that uses the temperature difference between warmer surface ocean water and colder deep ocean water to generate electricity. It highlights OTEC's ability to provide base-load power, operating 24/7, unlike intermittent sources like wind or solar.

Key Points:
1. Basic Working Principle:
Warm surface water heats a working fluid (like ammonia), which vaporizes and drives a turbine to generate electricity.
Cold deep water is used to condense the working fluid, completing the cycle.

2. Types of OTEC Systems:
Closed-cycle: Uses a working fluid in a closed loop.
Open-cycle: Uses seawater as the working fluid.
Hybrid systems: Combine both closed and open cycles for increased efficiency.

3. Benefits:
Provides a sustainable, clean, and renewable energy source.
Can operate in tropical regions where a sufficient temperature gradient exists.
Useful for remote islands and coastal areas lacking traditional energy grids.

4. Challenges:
High initial costs and location constraints.
The technology is still in the development phase, and improving efficiency is key to commercial viability.

5. Environmental and Economic Impact:

Minimal environmental footprint and helps reduce reliance on fossil fuels.Provides energy independence, especially for island nations.

The presentation concludes by emphasizing OTEC's potential to contribute to global sustainability, despite its current challenges.

1. Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon-423 603
(An Autonomous Institute, Affiliated to Savitribai Phule Pune University, Pune)
NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified
Department of Electrical Engineering
Ocean-ThermalEnergy Conversion (OTEC) :
Methods and Benefits
Roll No. Name PRN No.
40 RushikeshKshirsagar UEE22M1039
42 PremMule UEE22M1044
43 AdityaNaikwade UEE22M1045
44 ShrihariPakhale UEE22M1046
Guided By -
Name –Prof. P.S. Chobe
Designation –Asst. Professor
Course –RES (EE305A)
Presented By –Group No: 07
DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon
Self Learning Activity

2. Introduction to OTEC
2
❑Ocean-ThermalEnergyConversion(OTEC)isarenewableenergytechnologythatutilizesthe
temperaturedifferencebetweenthewarmersurfacewatersoftheoceanandthecolderdeep
waterstogenerateelectricity.
❑OTECcanoperatecontinuously,providingbase-loadpowerunlikeintermittentsourcessuchas
windorsolar.Thetemperaturedifferencerequiredisusuallyabout20degreeCelsiusormore,
whichoccursintropicalregions.
❑OTECisfirmpower(24/7),acleanenergysource,environmentallysustainableandcapableof
providingmassivelevelsofenergy.
DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

3. Heat Exchange: OTEC takes advantage of the natural thermal gradient between warm surface water (about 25-30°C)
and cold deep water (about 5°C or less).
3
Basic Working Principle
DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon
EnergyGeneration:Thewarmwaterheatsaworkingfluid,
suchasammonia,whichvaporizesandspinsaturbine
connectedtoagenerator,producingelectricity.
Cooling:Coldwaterfromthedeepoceanispumpedtothe
surfacetocoolandcondensethevaporizedworkingfluid,
completingthecycle.

4. ❑Thistemperaturegradientis
relativelysmall,soOTECplants
requirelargevolumesofwater
toproduceelectricity.
❑Thedeeperthewater,thecolder
itbecomes,usuallysourced
fromdepthsof600-1,000
meters.
4
Basic Working Principle
DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

5. Types of OTEC Systems
1)Closed-cycleOTEC:Aworkingfluid(ammonia,propane,orotherlow-boilingpointfluids)
circulatesinaclosedloop.Thefluidisvaporizedbywarmsurfacewaterandcondensedbycool
deepwater.Thevaporizedfluiddrivesaturbinetogenerateelectricity,andthefluidisthen
cooledandrecycled.
2)Open-cycleOTEC:Seawateritselfactsastheworkingfluid.Warmseawaterisevaporatedina
low-pressureenvironment,creatingsteamthatdrivesaturbine.Thesteamiscondensedbycold
seawater,producingfreshwaterasaby-product.
3)HybridOTEC:Itcombinesfeaturesofbothclosedandopen-cyclesystems.Itusesopen-cycle
togeneratesteamfromseawater,thenutilizesaclosed-cyclelooptoboostefficiencyandpower
output.
❑Closed-cycleOTECismoreefficientandstablebutrequirestheuseofaworkingfluid.
❑Open-cycleOTECislessefficientbutcanprovidedesalinatedwater.
5DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

6. Closed-cycle OTEC
1)Inaclosed‐cycleOTEC(CC‐OTEC)system,warmsurfaceseawaterprovidesheattoaworkingfluidwith
alowboilingpointtovaporizetheworkingfluidtodriveaturbinegenerator.
2)Hybridsystemscombinecomponentsofbothopen‐cycleandclosed‐cyclesystemstomaximizetheuseof
thepumpedseawaterthermalresourceavailabletoproducebothpowerandwater.Forexample,thesteam
generatedbyflashevaporationinOC‐OTECcanthenbeusedastheheattodriveCC‐OTECprocesses.
6DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

7. Open-cycle OTEC
1)Open‐cycleOTEC(OC‐OTEC)useswarmsurfaceseawaterastheworkingfluid,injectedintoavacuum
chamberwherethepressureisreducedbelowthesaturationvaluecorrespondingtoitstemperature,thus
causingflashevaporation.Theresultinglow‐pressuresteamexpandstodriveaturbinegenerator.
7DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

8. ❑OffshoreOTECreferstoOceanThermalEnergyConversion
systemsthatarelocatedawayfromthecoast,typicallyindeep
oceanwaterswherethetemperaturedifferencebetweenwarm
surfacewaterandcolddeepwaterissufficientforefficientenergy
conversion.OffshoreOTECsystemsareoftenmountedonfloating
platformsoranchoredstructures,allowingthemtoaccessdeeper,
colderwaters.
8
Offshore OTEC
DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon
Benefits of Offshore OTEC:
❑Access to Greater Temperature Gradients
❑Minimal Land Use
❑Energy Independence

9. Benefits of OTEC
❑ImmenseResource
❑BaseloadPower
❑DispatchablePower
❑Security
❑Renewable
❑LowRisk
❑CleanEnergy
❑Offshore
9DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

10. Environmental and Economic Impact
1)MinimalEnvironmentalFootprint:OTECplantshavealowimpactonmarineecosystems
whendesignedproperly.Theyavoidharmfulemissionsanddonotrequirefuel.
2)EnergyforRemoteLocations:OTECisparticularlyusefulfortropicalislandsandcoastal
regionsthatlackaccesstotraditionalenergygrids.
3)EconomicDevelopment:Byreducingrelianceonfossilfuels,OTECcanhelpislandnations
andtropicalcountriesachieveenergyindependence,loweringimportcosts.
❑Thepotentialenvironmentaleffects,suchasalteringoceancurrentsoraffectingmarinelife,are
minimalifdesignedwithcare.
❑OTECcandiversifyenergysources,makingeconomiesmoreresilienttoenergyprice
fluctuations.
10DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

11. Challenges of OTEC
1)HighInitialCosts.
2)LocationConstraints.
3)EnergyEfficiency.
4)TechnologicalBarriers.
❑OTECtechnologyisstillinthedevelopmentalphase,andcommercialviabilitydependson
overcomingtechnicalchallengesandimprovingefficiency.
11DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

12. Conclusion
❑OTECrepresentsapromisingrenewableenergytechnology,particularlyfortropicalregions,
offeringbothenergyproductionanddesalinatedwater.
❑Whiletherearechallenges,suchashighcostsandtechnicalbarriers,ongoingresearchandpilot
projectsshowthatOTEChassignificantpotentialtocontributetoglobalsustainabilityefforts.
12DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

13. References
1)A.Hossain,A.Azhim,A.B.Jaafar,M.N.Musa,S.A.ZakiandD.N.Fazreen,"Oceanthermalenergy
conversion:Thepromiseofacleanfuture,"2013IEEEConferenceonCleanEnergyandTechnology
(CEAT),Langkawi,Malaysia,2013,pp.23-26,doi:10.1109/CEAT.2013.6775593.
2)2)L.Meegahapola,L.UdawattaandS.Witharana,"TheOceanThermalEnergyConversionstrategiesand
analysisofcurrentchallenges,"2007InternationalConferenceonIndustrialandInformationSystems,
Peradeniya,SriLanka,2007,pp.123-128,doi:10.1109/ICIINFS.2007.4579160.
3)3)S.K.WangandT.C.Hung,"Renewableenergyfromthesea-organicRankineCycleusingocean
thermalenergyconversion,"ProceedingsoftheInternationalConferenceonEnergyandSustainable
Development:IssuesandStrategies(ESD2010),ChiangMai,Thailand,2010,pp.1-8,doi:
10.1109/ESD.2010.5598775.
4)4)A.Najafi,S.RezaeeandF.Torabi,"Sensitivityanalysisofaclosedcycleoceanthermalenergy
conversionpowerplant,"2012SecondIranianConferenceonRenewableEnergyandDistributed
Generation,Tehran,Iran,2012,pp.1-6,doi:10.1109/ICREDG.2012.6190461.
5)5)BimalK.Bose,"OCEANANDGEOTHERMAL RENEWABLE ENERGYSYSTEMS,"inPower
ElectronicsinRenewableEnergySystemsandSmartGrid:TechnologyandApplications,IEEE,2019,
pp.391-441,doi:10.1002/9781119515661.ch8.
13DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon

14. DEPARTMENT OF ELECTRICAL ENGINEERING, Sanjivani COE, Kopargaon 14
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