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1 INTRODUCTION
Nowadays, early in the 21
st
century around 90% of
world trade (by volume) is carried by the
international shipping and constitutes an essential
part of the modern world economy. Nowadays we
haveanaccesstothehightechnologyaswellasthe
adequate knowledge, skills, attitude and behavior.
These elements give us good opportunities and
adequatecompetences to lead theshipping indust
ry
to a more ecological and environment‐friendly sea
transportationsystem.
Unfortunately, if we look deeper in the shipping
industry development observed since the 19th
century, it may appear to the public and the media
thatthegrowthinthemarinepropulsiontechnologies
isnotadequat
etoourabilityand,whatismore,that
the sea transportation has not done much to reduce
theenvironmentalimpactssuchasemissionsoftoxic
gasesorpollutionatsea[3],[4].
Study of Green Shipping Technologies - Harnessing
Wind, Waves and Solar Power in New Generation
Marine Propulsion Systems
G.Rutkowski
GdyniaMaritimeUniversity,Gdynia,Poland
ABSTRACT:Thepurposeandscopeofthispaperistodescribethecomplexityo
f
thenewgenerationmarine
propulsiontechnologiesimplementedintheshippingindustrytopromotegreenshipsconceptandchangethe
viewofseatransportationtoamoreecologicalandenvironment‐friendly.Harnessingwind,wavesandsolar
power in shipping industry can help the ship’s owners reduce the operational costs. Reducing fuel
consumption results in producing less emissions and provides a clean source of renewable energy. Green
shipping technologies can also effectively increase the operating range of vessels and help drive sea
tra
nsportationtowardsagreenerfutureandcontributetotheglobalreductionofharmfulgasemissionsfrom
theworldʹsshippingfleets.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 10
Number 4
December 2016
DOI:10.12716/1001.10.04.12
628
Figure1.Comparisonoftheenvironmentalimpactsbroughtbyshippingobservedinthelast200yearsofseatransportation
relatedactivities.Source:TeekayEnvironmentalprogram,Nov.2016.
Figure2.ComplexityofMarinePropulsionTechnologies.Source:Inerjywebsite[7].
Keep in mind that around 200 years ago ocean
going sailing ships were already reaching speeds of
16knotsormoreandcarryinggoodsacrosstheglobe
without using a drop of oil. Best of all, they also
released no harmful emissions or pollution, being
always a part of very
ecological and environment‐
friendlyseatransportationsystem(seeFigure1)[4].
But since then, the world shipping industry has
strayed off the green path and the benefits of using
wind power on‐board large ships was forgotten. In
such case, we must draw the following conclusion:
nowadays there is no adequate
progress in green
shipping industry and we must concentrate how to
moveourfleetagaintoagreenpathandchangethe
view of the sea transportation to a more ecological
andenvironment‐friendlysystem.
Itiscrucialthatcurrentlywehave awiderangeof
modern marine green technologies available on the
market, used to enhance the performance and
sustainability for the oceangoing vessels (see Figure
2). These technologies range from simple with low
capability such as traditional sails or small scale
renewables wind power
plants or solar modules to
very capable and highly complex systems such as
LNG&dualfuelpowerplants.Inthisarticleweare
goingto concentrateon a fewmodern marine green
shipping technologies which harness wind, waves
andsolarpowertosupportmarinepropulsionsystem
ofnewgeneration.
2 HARNESSINGWIND,WAVESANDSOLAR
POWER
Whenever we are talking about harnessing wind
powerinmodernmarinepropulsionsystemwemust
keep in mind, that whether using flexible or rigid
sails,the aerodynamic efficiencies on the vessels are
limitedby the tip speed ratio, or the ratio of the
air
foil’sspeedthroughtheairtothewindspeed.Taking
allofthisintoconsideration,foilingcatamarans,like
theAmerica’sCupraceboats,inspecificsituationare
abletosailfasterthanthewind,andthereforeachieve
tipspeedratios wellaboveone.Thisallowstheirair
foils (sails) to
obtain a higher propulsion efficiency.
Unfortunately,thisworksgreatonlyonaracingboat,
butwhenloadeddowntothecargoshipswithallthe
needsofashipservingapurposeotherthanracing,
the efficiency is reduced by the lack of ability to
achieve the same tip speed
ratios. Also, when the
vessel is intentionally moving more slowly than
optimal,e.g.whenlimitedbyacomfortinaseaway,
performing mission objectives not involving transit,
orsailinginanon‐optimaldirection,thewindenergy
is wasted. However, even in such specific scenarios
we still can take into consideration
harnessing wind
power to the new generation wind sails, Flettner
rotorsorapowergenerationplantwhichcansupport,
but not necessary replace, traditional marine
propulsion systems reducing shipping operational
costandemissions.
WithSkySailstheworldwidepatentedpropulsion
system[9]themoderncargoshipscanusethe wind
as
a source of power to support the main marine
propulsion system and not only to lower fuel costs,
butalsosignificantlyreduceemissionlevels.SkySails
systemconsists of three main components: a towing
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kitewitharope,alaunchandrecoverysystem,anda
control system for an automated operation. The
system can be installed effortlessly as an auxiliary
propulsion system on both newly built and existing
vessels harnessing the wind as a cheapest, most
powerful,andgreenestsourceofenergyonthe
high
seas.TheSkySailspropulsionsystemisefficient,safe,
and easy to use – and the fact that wind is cheaper
thanoilmakesSkySailsoneofworld’smostattractive
technologies for reducing the operating costs and
emissions.
Figure3. Comparison the SkySails Marine system with
EMP’s Energy Sail technology installed on Aquarius Eco
Ship. Sources: SkySails [9] and EcoMarine Power [6]
websites.Nov.2016.
Eco Marine Power (EMP) Co. Ltd. [6] decided to
goonestepaheadofferingtogreenshippingindustry
their unique design concept and the innovative
technologywellknownonmarketasAquariusMRE
System with revolutionary EMP designed Energy‐
Sails(seeFigure3)asarenewableenergycollectors.
Their vision is
to create a sustainable future for
shipping where our trade and transport routes will
once again see ships utilize wind power but also
harness the power of the sun via solar modules,
which can reduce emissions, but also save ship
ownersandshippingcompaniesmoney byreducing
fuelcostseven
whenashipisinportoratanchor.
Solar PV is an excellent technology and should
augment power supplies whenever possible. Planet
Solar even made theirMS ‘Turanor’recognizable by
makingitsailaroundtheworldonPVpoweralone.
Thetroubleisthatitrequiresa greatdealofareato
obtain enough power to propel a ship.
As with
the‘Turanor’,muchofthefunctionalitywassacrificed
to maximize unshaded module area. This isn’t
practical on a typical cargo ships and scale doesn’t
alter these dynamics. However, using the solar PV
technology, we still can support traditional marine
power plant and by reducing fuel consumption
significantlyreduce
emissionlevels.
The EMPʹs Energy Sail technology [6] allows the
shiptoharnessthepowerviaacomputercontrolled
rigidsailorrigidsailarray.Typically,anEnergySail
array would be incorporated into an Aquaris MRE
solution but the installation of an Energy Sail as a
standalonedeviceis
alsopossible.TheAquariusMRE
System is an advanced integrated system of rigid
sails, solar panels, energy storage modules that will
enable ships to tap into the renewable energy by
harnessingthepowerprovidedbythewindandsun.
The array of rigid sails will be automatically
positioned to best
suit the prevailing weather
conditionsandcan be loweredand storedwhen not
in use or in bad weather. The array of rigid sails is
based on EMPʹs Energy Sail technology (patent
pending) and can even be used when a ship is at
anchororinharbor.ClearlytheEnergy
Sailisunlike
any other sail. All EMPʹs hybrid marine power and
marine renewable energy solution incorporate the
Aquarius Management and Automation System or
AquariusMAS.TheAquariusMASisacosteffective,
alarm handling, performance monitoring and data
logging platform suitable for a wide range of ships.
Using
the Aquarius MAS system CO2, NOx & SOx
emissionscanbemonitoredorcalculated.Thesystem
is based upon the type approved KEI 3240 Data
Loggerwhichisalreadyinuseonhundredsofvessels
[6].
An Energy Sail can include marine grade solar
panelseitheronthesailitselfor
locatednearthesail.
TheflexiblenatureoftheEnergySaildesignwillalso
allowforittobeupgradedduring thelife‐cycleofthe
shipit is fitted to sothatnewer technologies can be
incorporatedas they become availablesuch as more
efficientsolarmodulesorpanels.
Othertechnologies
can also be fitted to the Energy Sail including wind
power generating devices. In addition to being
suitableforocean‐goingshipsincludingRoRovessels,
cruise ships and large passenger ferries, several
variationsoftheEnergySailarebeingdeveloped[6]
which will be suitable for smaller vessels including
UnmannedSurfaceVessels(USVʹs)and autonomous
shipsandvessels.
Technologies associated with the Energy Sail are
also suitable for the offshore renewable energy
projects and land‐based renewable energy projects.
An example of how the Energy Sail could be
incorporated into a modern ship design is the
Aquarius Eco
Ship. This low emission‐sustainable
shipdesignconceptincludesanEnergySailarrayand
othertechnologiessothatsolar&windpowercanbe
usedto reducefuel consumption and lower noxious
gasemissions.
EMPʹs Hybrid Power or Hybrid Marine Power
(HMP) systems [6] are another example of low
emission,
cost effective an attractive return on
investment solutions for the vessel owners and
operators. EMP is currently developing a range of
cutting edge solar‐electric hybrid powered ferries,
workboats and other vessel concepts. These designs
will incorporate a range of technologies including
computersystems,flexiblemarinegradesolarpanels,
energy
storage modules, power management and
hybrid propulsion with highly efficient electric
motors,generatorsandlithiumbatteries.EcoMarine
Powerʹs vision is to provide a clean, cost‐effective,
lowpollutionandefficientformofwatertransporton
urbanwaterwaysacross theglobe that willnot only
benefit the environment but also
reduce their
operatingcosts.
Another quite interesting solution for green
shipping concept has been implemented by
GermanyʹsEnercon[2],thethird‐largestwindturbine
manufacturerandownerof‘E‐Ship1’.The‘E‐Ship1’
wasbuiltbyGerman shipbuilderLindenau Werft in
Kiel as RoLo (Roll‐on/Roll‐off)
cargo ship used to
transport wind turbine components. The ship is
equippedwithfourlargerotor‐sails(wellknownas
Flettnerrotors), which are rotating at variablespeed
to create lift on the cylinder body, supporting the
ship‐like sails by means of the Magnus effect(the
perpendicularforcethatis
exertedonaspinningbody
movingthroughafluidstream).
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The fundamental configuration of the rotor
propulsion system has been initially created already
in the 1920s by German engineer Anton Flettner. In
October 1924, the Germaniawerft finished
construction of a large two‐rotor ship named
‘Buckau’. The vessel was a refitted schooner which
carried two cylinders (rotors) approximately 15
metres
high and 3 metres in diameter, driven by an
electric propulsion system of 50HP (37kW) power.
The‘Buckau’setoutonherfirstvoyage, fromDanzig
to Scotland across the North Sea, in February 1925.
Therotorshipcouldtack(sailintothewind)at20‐30
degrees,
whileavesselwithatypicalsailrig,cannot
tack closer than 45 degrees to the wind, hence, the
rotors did not give cause for concern in stormy
weather.Nextyearin1926,‘Buckau’,nowrenamedas
‘BadenBaden’sailedtoNewYorkviaSouthAmerica
anddespite having completed trouble
free crossings
oftheNorthSeaandAtlanticthepowerconsumedby
spinning15mtalldrumswasvastlydisproportionate
to the propulsive effect when compared with
conventional screws (propellers). As the Flettner
system could not compete economically Flettner
turnedhisattentiontootherprojects,suchashisrotor
aircraft.
The
innovation used on ‘E‐Ship 1’ is the
propulsion system [2], which contains four modern
Flettnerrotorsworkingtogetherwithtwotraditional
propellerspropulsionsystem.The‘E‐Ship1’bridgeis
locatedatthebow,andhasthreedecksandtwoport‐
relatedlong‐boomcraneswithpayloadcapabilitiesof
80and
120tonnes.Theshiphasarearramp, andcan
function as a RoLo cargo ship. The vessel is 130
meters in length and 22.5 meters wide, 6 to 9 m
draught, with tonnage 10500 DWT and maximum
speed17.5knots(32.4km/h).Itisequippedwithfore
andaft
maneuveringthrustersandhasaniceclassGL
E3 hull rating. The ‘E‐Ship 1’ is equipped with nine
Mitsubishimarinedieselengines with atotal output
of 3.5MW. The shipʹs exhaust gas boilers are
connected to a Siemens downstream steam turbine,
whichinturndrivesfourEnercon‐developed
Flettner
rotors. These rotors, resembling four large cylinders
mountedontheshipʹsdeck,are27meterstalland4
meters in diameter. The ship made its first voyage
withcargoinAugust2010,carryingnineturbinesfor
Castledockrell Wind Farm from Emden to Dublin,
Ireland. On 29 July 2013,
Enercon provided a press
release claiming a potential for ‘operational fuel
savings of up to 25% compared to same‐sized
conventional freight vessels’ after 170000 sea miles,
actualperformancefigureswerenotprovided.[2]
In2009similarconceptthatwouldutilizeFlettner
rotors as means of reducing fuel consumption has
been
developed by Finland‐based maritime
engineeringcompanyWärtsiläinassociationwiththe
Finnish ferry operator Viking Line. Because of
researching and testing different green shipping
technologies Wärtsilä, in September 2016 during
SMMconferenceinHamburg,hassetouthervisions
forthefutureoftheshippingindustrywhichinclude
rotor
ships concept as a very effective and
environmentalfriendlysolution.Theworkonfuture
visions[5]hasbeenpromptedbytheinevitableeffect
thatgrowingglobalenergydemandandincreasingly
stringentenvironmentallegislationtocombatclimate
changewillhaveontheshippingsector.Additionally,
Wärtsilä assesses various emerging trends, such as
sharingeconomies,newbusinessmodelsenabledby
thenewdigitaluniverse,thehuge growth inenergy
storage capacity, and new affordableʹgreenʹ energy
sources, since they represent both challenges and
opportunitiesforthefutureofshipping(seeFigure4).
The concept of rotor ships is not new, but up to
now,themainideahasbeentohavetherotorscreate
additional propulsion from the wind, thereby
producingfuelconsumption.ButGermanresearchers
[8] are further developing the concept to create
synthetic gas (power to gas or P2G). The rotating
turbinekeptinmotionbytheshipʹskineticenergyis
used to generate electricity, which then creates
synthetic gas by means of electrolysis. The gas can
then be used as a fuel and to generate electricity as
needbe.
Nowadays, the THiiiNK Holding organization
describes an improved version of the Flettner Rotor
thatisretractableandsupplementedbyanadditional
controlsurface.Thepage[1]claimsthat‘Thesystem
hasbeendevelopedandtestedbothintanktestsand
infull‐scaleseatrials.Thedesignimprovementclaims
include improved rotor performance (by 50% or
more),andanimprovedinternalrateofreturn(IRR)
comparedtoastandardrotor(upto
55%)’.
Figure4.ComparisonE‐Ship1rotorshipbyEnercon(ontheleft)withWärtsiläʹVisionsofFutureShippingʹ(ontheright
top)andSegelenergieproject(onthe rightbottowcorner).Sources:Enercon[2],Wartsila[5]andSegelenergie[8]websites.
Nov.2016.
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There is also another quite interesting green
technology proposed by Wallenius Wilhelmsen [10]
forzero‐emissioncarcarrier(seefigure5)withlength
overall250m,height30to40m,beammoulded50m,
design draught 9 m, design speed 20 knots
(maximum)and15knots(inservice),vehicle
capacity
10000 cars (based on todayʹs standard units) with
design cargo deck area 85000 m
2
and eight cargo
decks, of which three are adjustable in order to
accommodatehighandheavyvehiclesand
equipment.
Figure5.Comparisonzero‐emissioncarcarrierproposedby
Wallenius Wilhelmsen (on the left) with zero‐emission
AeromancersystemproposedbyInerjy(ontheright).
Sources:WalleniusWilhemsen[10]andInerjy[7]websites.
Nov.2016.
The hull design is pentamaran with design
materials aluminium and thermoplastic composites.
Shipwillbeequippedwithsolarpanels(3x800m
2
)
whichshouldgenerate2500kWoutputenergy,wind
sails(3x1400m
2
),fins(12x210m
2
),fuelcellsenergy
output 10000 kW, pod propulsion system 2 x 4000
kW. As per plan ship will take advantage of solar
energy, wind energy and waves energy and utilize
such energy for ma noeuvring, sailing and all on‐
board systems. For energy carriers system will use
hydrogen,electricity,fuelcells
andhydraulicenergy.
Anotherveryinterestingzero‐emission an
innovative propulsion‐scale wind power system for
longrangehighenduranceshipshasbeenpresented
by ‘Aeromancer’ Inerjy [7]. The solution enhances
system capabilities by providing indefinitely
sustainableelectrical andpropulsion energy without
fuel.Itacceleratesdevelopmentcyclesbyprovidinga
scalable technology platform that can modularize
vessel design, eliminating the need for holistic
designsforeveryvesselpurposeaswellasofferinga
simpler alternative to the complex state of the art
hybrid energy systems. This simplification allows a
framework suitable for streamlined procurement
strategies, allowing ‘building blocks’ to be defined
and sourced from different vendors. It reduces
sustainmentcoststhroughdrasticcrewreductionplus
elimination of fuelling infrastructure. Finally, it
mitigatestechnicalrisksthroughmodularizationand
simplifiedsystemsarchitecture.
The goal of ‘Aeromancer’ [7] is to have high
capabilityinaverysimpletodesign,implement,and
maintainplatform.This
isaccomplishedwithawind
turbineastheprimarypowersourcecombinedwitha
large battery buffer using an all‐electric DC bus
architecture.
Thewindturbineandbatterytechnologiesarethe
two primary enablers, and are enhanced by high
efficiencysubsystems.TheTurbineEcoVert75™was
designedfordistributedgeneration
applications,like
powering schools, retail stores, etc. The key
requirementsfocusedonpeoplelivingandinteracting
near the machine. It is technically called a pitch‐
controlled H‐VAWT, a design originally modelled,
prototyped, and tested by McDonnell Aircraft
Corporation (now Boeing) in the early 80’s. It
producesahealthy70kW
ina21knot(10.8m/s) wind
at 32 rpm. With a few hardware and software
modificationsitisanexcellentmachineforuseaboard
a vessel. The EcoVert75™ has less than ¼ the head
massandathirdthe stormwindloadscomparedto
other similarly sized turbines and less
than ½ the
operational blade speeds of conventional turbines at
similar power outputs, very low noise & safe blade
pathforvesseloccupants,highpowerefficiency(Cp>
0.5atsome windspeeds) and the ability to produce
propulsionthrustdirectlywiththeturbineinsteadof
convertingallthewind
powerintoelectricity(saving
conversionlosses).
Propulsionscale wind turbine power is the heart
ofthe‘Aeromancer’concept.Acommonmetricused
to describe a sailing vessel is the sail area
displacement ratio (SA/D). This basically allows
vessels to be compared to each other in terms of a
powertoweight
ratio.ThehighestSA/Dratiotested
with a turbine thus far has been <5. Aeromancer’s
target SA/D is 11. Given that ocean going sailing
vesselsare commonly around 15, and racing vessels
above 20, there is opportunity for advancement in
powertoweightratiometrics.
‘Aeromancer’smainhullisdedicated
tolittlemore
than housing crew and mission spaces. In normal
conditionsthehullisjackedupclearofthewatersoit
has no main running surfaces. Given the absence of
dieselsorrelatedsystems,allspaceswithinthema in
hullcanbeenvironmentallycontrolled,andrelatively
littlemechanicalspace
isnecessary.Alargeenclosed
garageisprovidedforstorageofa RHIB(rigid‐hulled
inflatableboat)andunmannedsystems.
In green shipping industry, the battery
performanceisadvancingatarapidpace,andisnow
providing critical energy supply on modern ships
regularly. From work vessels like the
impressive
‘EddaFreya’topurebatteryelectricferries
likethero‐ro‘Ampere’,andmanymore,Li‐chemistry
batteries are developing a maritime propulsion
legacy. Numerous battery cell manufacturers are
promoting solutions for marine applications.
Traditionalclassificationsocietiesarealsodeveloping
standards for large scale on‐board Li based energy
storage.
On ‘Aeromancer’ the 2500 kWh energy storage
system will be divided into the two outrigger hulls,
along with the DC‐AC converters, the propulsion
motorsanddrives, andH‐VAWTequipment.Cooling
requirementsaresuppressedbythehighlyparalleled
architecture.
However, not all purposes are suitable for wind
poweredbattery electric
shiptechnology. Asof now
thebatterieswillholdfarlessenergythanlargefuel
tanks, but most regions of the world’s oceans have
abundantwindenergyavailableonaregularbasisso
that there isn’t a need to carry weeks or months of
energy on board. For instance, using
solar PV
technology, the ‘Aeromancer’, would require more
than10000SQFT(≈929m
2
)ofunshadedmodulearea
toderiveequivalentpowerproductiontotheEcoVert,
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in a Caribbean type environment. EcoVert can
maintain tip wind speed ratio and optimal angle of
attackindependentlyofvesselcourseandspeed.The
batteriesallowtheextraenergytogetstoredforlater
use.
3 CONCLUSION
Theinnovativeingreenshipping industryincluding
hybrid marine concepts which give us
possibility to
harness wind, waves and solar power and support
ship’s propulsion systems and power generation
plants will not only reduce fuel costs, but will also
play an important role in assisting ship
owners/operatorsmeettherequirementsofoperating
inEmission Control Areas (ECA), marine parks and
nature reserves etc.
Marine wind, waves and solar
powersystemscanbeinstalledonlargeshipssuchas
carcarriers,bulkers,passengerferriesandoiltankers
plusonsmallershipssuchascommuterferries,river
boatsand recreationalvessels. From the small
powered pleasure craft and ferries to large super‐
tankers,thelimitlessenergy
ofthewind, waves and
suncanbeusedtohelppowershipstherebyreducing
fuel consumption, the emission of greenhouse gases
(GHGs) and noxious exhaust emissions. Green
shipping can also effectively increase the operating
range of vessels and help drive sea transportation
towardsagreenerfutureandcontributeto
theglobal
reductionofharmfulgasemissionsfromtheworldʹs
shippingfleets.
Additionally, solar‐electric commuter ferries will
fulfilanimportantroleinenergy‐efficientcitiesnear
harbors,baysandwaterwaysintheyearsahead.Not
onlywillthesevesselsreducefuelcostsbutalsohelp
reduce air and noise
pollution thus improving the
qualityoflifeinthesecities.
BIBLIOGRAPHY
[1]Anon, Folding Flettner Rotor Wing. Thiiink Holding.
Retrieved 12 October 2015. (http://www.thiiink.com/
advantages‐rfr‐technology).
[2]Enercon E‐Ship 1 A Wind‐Hybrid Commercial Cargo
Ship4thConferenceonShipEfficiencyHamburg,23‐24.
September2013,(http://www.ship‐efficiency.org).
[3]Environmental and Social Impacts of Marine Transport
in the Great Lakes
‐St. Lawrence Seaway Region,
Executive Summary prepared by Research and Traffic
Group, January 2013, http://www.greatlakes‐
seaway.com,accessed15Nov.2016.
[4]EnvironmentalLeadershipProgram(ELP)implemented
inTeekaycorporation,Nov.2016.
[5]Wärtsilä, Visions of Future Shipping, SMM conference
andexhibitionbeingheldinHamburgfromSeptember5
to9,
2016.(www.wartsila.com/shippingscenarios).
[6]http://www.ecomarinepower.com, accessed 19 Nov.
2016.
[7]http://www.inerjy.com/,accessed19Nov.2016.
[8]http://segelenergie.de
(http://www.renewablesinternational.net/), accessed 19
Nov.2016.
[9]http://www.skysails.info/english/,accessed19Nov.2016.
[10]http://www.walleniuslines.com/,accessed19Nov.2016.