CARGO HANDLING

January 2013 29

WorldCargonews

The Georgia Ports Authority(GPA) has become the first portoperator in North America toimplement ERTGs powered off aconductor rail, beating APM Ter-minals’ Pier 400 Terminal in LosAngeles to the starting post.

In December, the GPA un-veiled its first four KonecranesERTGs at its Garden City Termi-nal in Savannah and reiterated itsearlier announced plan to convertits entire fleet of RTGs to electri-cal power by 2022. GPA currentlyhas 110 RTGs - a number ex-pected to grow to 169 at build out.

The GPA selected the drive-in conductor bar system fromConductix-Wampfler, the RTGconversions were carried out byKonecranes, and the power systemwas supplied by the local utility,Georgia Power. GPA is the firstto use Conductix-Wampfler’s new“Drive-in-L” system that uses lin-ear motors instead of hydraulicsor pneumatics to engage the con-necting arm from the RTG intothe conductor rail automatically.

Best optionRichard Cox, GPA’s general man-ager of equipment and facilityengineering, explains that theproject team considered cable reelsand an overhead pantograph aswell as conductor bars. Cable reelshad the advantage of fibre opticcores for data, but the length ofGPA’s stacks were an issue. TheRTG blocks at Berths 4, 5 and 6are 2400 ft (732m) long and areintersected by several vehiclecrossing points. The GPA lookedat terminals using cable belt cov-ers at crossing areas, but Cox saidhe had concerns about debrisbuilding up in the channel.

The big advantage of a con-ductor bar was the availability ofan automated drive-in option,which is not yet offered with ca-ble reel systems. Garden City Ter-minal occupies 1200 acres and hasexperienced a sustained period of+10% traffic growth per year, atthe same time as transitioningfrom a top lift to a full RTG ter-minal. Managing that process re-quires a great deal of flexibility -RTGs are moved as far as 1.5 milesbetween different areas of the ter-minal. Disconnecting and recon-necting a cable would be possible,but would be a significant burdenon maintenance personnel.

The ability to use the conduc-tor rail as a fixed point of refer-ence for autosteering and con-tainer positioning was not a fac-tor for GPA. It will continue touse the Sattel (now Identec) GPSsystem for container position in-formation, and Konecranes DGPSsystem for autosteering.

SafetyWith regard to the risk of a vehi-cle collision with a conductor rail,the GPA believes it is not a sig-nificant issue. Unlike some westcoast terminals, it does not oper-ate top lifts in RTG blocks andthe conductor rail mounting polesare encased in 4ft-dia concreteblocks to protect them from ter-minal tractors and road trucks.

Ultimately, however, keepingvehicles away from the conduc-tor rail is about traffic flow andthe GPA is confident it can man-age this. “We were concernedabout collisions, but we haven’thad any close calls yet,” said Cox.Conductix-Wampfler’s globalmarket manager, ports, Dr Law-rence Henesey, added thatconfiguring the RTG blocks sotheir profile does not extend pastthe conductor rail is another im-portant point in this regard.

Another risk that other termi-nals have identified is an emptycontainer being blown off a stack

and hitting the conductor rail. Thiswould most likely happen whenthe terminal was shut down dueto bad weather, and as such is moreof a maintenance than a safety is-sue. One of the attractions of aconductor rail is that it is “fairlyeasy to replace a section and westill have the diesel to operatewithin the stack,” added Cox.

One area where GPA didchange the layout recommendedby Conductix-Wampfler is in thegap between the connector armand the conductor bar. The con-nection side of the RTG is the op-posite side of the gantry portal tothe driver access stairs and the roadtruck lane, but personnel access isneeded for the electrical room.

GPA engineer ing wantedenough distance between the con-ductor rail and the RTG to allowfor a person wearing a backpackto climb the stairs without get-ting caught in the rail and to per-mit maintenance truck access, soextended the gap to 4ft 8 ins.

So far, so goodThe conductor rail and the Drive-in-L system were installed byConductix-Wampfler whileKonecranes did the integrationwith the RTG electrical and con-trol system. Cox explains thatKonecranes had a considerablework load as the GPA did notwant the ERTG system to bestand-alone from the main cranecontrols. Konecranes integratedthe ERTG functionality into the

crane PLC and the CMS (cranemonitoring system) and adaptedthe drive system to support regen-erative energy from the RTG low-ering cycle.

After two months of opera-tions the GPA is pleased with howthe conductor rail system has per-formed. As with any new systemthere have been teething issues,including getting the alignmentbetween the connector arm andthe rail right on both sides of therail, reducing nuisance trips andsome software issues. Cox stressedthat these are really “fine tuning”points and there have been nomajor hardware problems.

As far as the drivers are con-cerned, acceptance has not beenan issue. They were keen to vol-unteer for training and like thesmoother, quieter operation. Un-til recently the GPA ran diesel-powered quay cranes and driverswere glad when these were elec-trified as it removed diesel fumesaround the cab. The ERTGs areviewed with the same enthusiasm.

SavingsGPA calculates that converting amachine to ERTG reduces fuelconsumption “by an estimated95%.” The current fleet of 110machines use around 1.57M USGof diesel (almost 44M litres) a yearand electrification would cut thatto 78,000 USG. At its maximumcapacity of 6M TEU, the GPAwould have around 169 RTGsconsuming around 5.97M USGof diesel a year. Electrifying a fleetthat size would save GPA nearlyUS$10M a year in power costs.

GPA is also expecting a sig-nificant saving in downtimethrough reduced genset mainte-nance. When it converted its STScranes from diesel to electricity,downtime dropped from 1.2% ofoperating hours to 0.5%. Cox saidhe expects a very similar perform-ance from the ERTGs. The pay-back period for electrificationdepends on fuel and energy costs,but is expected to be within the4-5.5 year range.

Staying with RTGsCommitting to electrifying up to169 RTGs indicates that the GPAdoes not intend to transition toRMGs in the short to medium

All-electric RTGs hit the USAThe United States now has fourterminals running or installingelectrically-powered RTGs andmore look set to follow

Set-up of the first installation inSavannah, using Conductix-Wampfler’s Drive-in L system.Oversized concrete mountings werelaid to protect the rail from vehicles

The significant increase in thenumber of terminals opting forRMG/ASC yards is a boomfor cable reel suppliers. Termi-nals typically need ≥ 3 yardcranes for every STS crane.Cavotec has won three separateorders for new equipment atDubai Port World’s new T3 de-velopment in Jebel Ali: long traveland spreader reels for the STScranes from Trans Gulf PortCranes (10) and ZPMC (nine),25 reels for the ZPMC ASCs and25 reels for the TGPC ASCs.

The group is supplyingsimilar equipment for theDPW-led Rotterdam WorldGateway terminal in Rotter-dam, This indicates thatCavotec will be supplying reelsfor the 50 ASCs DPW has or-dered from Gottwald. Cavotecpreviously announced an or-der for cable reels for the 11STS cranes and three bargehandling cranes, all fromZPMC, for this project. ❏

Cavotec reelsthem in!

When your customers want to go beyond we have the solution.

WWW.VAHLE.COM

Meet us from 12 – 14 March 2013:

TOC Asia, Hong Kong, booth C26

29_WCN_Jan_2013.indd 1 06/02/2013 18:40:38

January 201330

WorldCargonews CARGO HANDLING

term. Cox said GPA has consid-ered RMGs, but their lack of flex-ibility is a drawback. RMGs arestuck on a single block and GPAwould need 50-60 more machinesto cover its massive facility.

A key part of the GPA’s elec-trification plan is a more detailedstudy on how the RTGs usepower, so it can better design asystem for the whole terminal andget a clearer picture of budgetaryimplications. The Electric PowerResearch Institute (EPRI) has in-stalled equipment on two conven-

Paul Vahle GmbH reports contin-ued strong interest in conductorrails for ERTGs, although it can-not confirm project details at thispoint. Vahle has also had to tacklethe safety issue with potential UScustomers and one method it hasidentified that could help addressthe concern is putting the con-ductor rail inboard the RTG legs,between the leg and the container.This would also allow safer accessto tyres and long travel gear.

Other markets have different

Staying on the rails

Italy-based Elettrotek Kabelmay be a relative newcomer tothe market (the company wasfounded by experienced pro-fessionals in Bagnolo in Pianoin 2001), but its extensive rangeof cables includes designs for allkinds of harbour cranes and ithas also achieved considerablesuccess in the Italian automa-tion and robotics markets.

The company has beengrowing on a global level andhas subsidiaries in Europe,North America and Asia, win-ning business in the crane ca-bles, drag chains, festoon sys-tems and marine and offshoresegments. It says its strengthsare ready product availabilityfrom stock, high quality andoptimal customer service.Wherever possible, the com-pany promotes halogen-freeand low smoke materials evenwhen these are not necessary.

In the ports sector,Elettrotek works with OEMs,power systems contractors andend users, and says that the drivetowards ERTGs and ASCs isproviding it with very strongbusiness opportunities. ❏

Elettrotecgrowing

West Basin Container Terminal in the Port of Los Angeles is now runningRTGs with the cable reel carrier system from Paceco Corp

tional RTGs and two ERTGs toprovide detailed data on the en-ergy usage characteristics of indi-vidual machines. EPRI and otherresearchers will use the data todetermine the amount of regen-erative energy produced by anERTG cycle. The GPA did simi-lar research when it convertedSTS cranes from diesel and foundthat an STS crane generates elec-tricity for 18 minutes every hour.

The study could affect the siz-ing of conductor rails. The firstfour ERTGs are running on a

480v rail sized to operate fourRTGs at a time at any stage of theduty cycle - so four RTGs couldall hoist their rated load at thesame time. The study will also lookat whether this is needed acrossthe whole terminal.

More to followWhile major greenfield and rede-velopment projects are tending tofavour RMGs and ASCs, there aremany RTG terminals in the USthat are under pressure to elec-trify their machines. There arearound 250 RTGs in Californiaalone and other big RTG termi-

nals include Charleston (43) andBayport Houston (36).

Three other terminals in theUS are known to be installingERTG systems, including AMPTPier 400 terminal, which is alsousing a conductor rail fromConductix-Wampfler. The systemis now expected to be operationalin February or March this year. Dr.Henesey said it had been hit withsome delays due to “extraordinaryevents” like the ILWU labour dis-ruption, but is now progressing.

WBCT’s cable trolleyIn another development, West

Basin Container Terminal(WBCT) in Los Angeles has in-stalled the Paceco Corp cable reelcarrier (CRC) ERTG system onthe first two of six RTGs. TheCRC uses a cable reel. However,the reel is not mounted on theRTG, but runs next to it on a trol-ley (the CRC). Paceco began theWBCT project some time agobut, as previously reported, therewas a problem with certification;the cable was not acceptable to theCity of Los Angeles because it wasmade to a European CE standard.This issue has now been resolvedand WBCT will not be requiredto change the cable.

The CRC has four solid rub-ber tyres and is attached to theRTG by two towing arms that canbe raised out of their mountingslots when the RTG needs tomove block. The trailing cableruns along the ground in a guidetrough made out of 10 gauge steel,which also acts as the guide tokeep the CRC straight. The CRCis the reference point for an op-tional autosteering system thatuses two laser range finders tomonitor the distance between thetrolley and the RTG and correctany deviation automatically.

Paceco’s chief engineer SunHuang said a laser range finderautosteering system is more reli-able than GPS. GPS is often usedfor container position informationas well, but Paceco has installedencoders on the hoist and trolleydrive and tags in the ground forthis requirement at WBCT.

With small diameter cable, theCRC system can support up to750ft of RTG travel in a singledirection at the RTG’s conven-tional (130 m/min in this case)speed. If the cable feed is from thecentre of the block, long travelfrom a single cable reel could beas much as 1500ft. The cable doeshave to unplugged and recon-nected manually if the RTG needsto change block, but Huang saidthe system is 460v and does notrequire a certified HV specialist.

While APMT and GPA haveopted for conductor rails, Huangsaid the CRC is a good solutionfor terminals that are concernedabout safety in a mixed top pick/RTG operation. It also has the ad-vantage of requiring minimal fixedinfrastructure - the cable channelis the only thing that needs to befixed down, and it is mounted us-ing small dynabolts.

Next to install the CRC willbe Seaside Transportation Services(Evergreen) at berths 226-336 inLA. Last month the South CoastAir Quality Management DistrictBoard (AQMD) approved a grantof US$1.87M to Seaside to coverthe cost of three CRC systems and50% of the transformer cost.

High voltage optionOperating voltage and (un) plug-ging the cable are key issues with

a cable reel system. Where a ter-minal has in-house resources tosupply enough 480v power, it mayprefer to step down voltage be-fore the RTG connection. Thedisadvantage of this approach is avery large and heavy cable is re-quired to meet the electrical cur-rent demands of an RTG at 480v.

Using 4160v supply and thenstepping down the voltage on theRTG itself allows a much smaller,lighter medium voltage cable tobe used. As previously reported,California-based ESL Power Sys-tems, Inc has developed a safety-interlocked fused disconnect sys-tem that enables terminals to run4160v power supply directly toRTGs without requiring a 4160vbreaker at the substation for eachRTG. Between four and six RTGscan be fed off a single 4160Vbreaker, and cable lengths up to300m (984 ft) can be achieved,allowing a single cable reel to sup-port a 600m (1968 ft) block witha centre feed arrangement.

ESL’s safety interlock systemprevents a MV cable from beingremoved or connected under loador while there is any residual cur-rent in the cable or connector. Asingle RTG cable can be safelydisconnected without tripping theupstream breaker and disruptingpower supply to other RTGs. Thissystem was first implemented andtested by SSA Marine in Panamaand ESL now has over 100 unitsin operation worldwide. ❏

concerns; dust and sand accumu-lation are a big issue in the Mid-dle East, for example. Vahle’s prod-uct manager Jürgen Henkel saidthat mounting the rail so the slotsopen to the bottom makes it dif-ficult for sand to stick, but theycan be safely cleaned periodicallywith compressed air. Vahle is alsoworking on two projects usingconductor rails for STS crane trol-ley power applications, one withAPM Terminals and another withcrane maker ZPMC. ❏

France-based Gaussin Manu-gistique is launching a new vari-ant on its ATT (automotive ter-minal trailer) product, ATT Lift.While ATT is Gaussin’s alterna-tive to conventional terminal trac-tor/trailer sets, ATT Lift is an al-ternative to straddle carriers, as itis self-buffering at the stackingcrane interface. The ATT Liftchassis has movable containerguides and a lifting/loweringstroke, and it matches with a dock-ing station at the stack interface.

The docking station allows theATT to decouple when is deliv-ering/retrieving a container to/from the CY, so it no longer hasto wait to be serviced by the stack-ing crane. This saves time com-pared to conventional RTG ter-

minals, but it also means, saysGaussin, that ATT Lift can be usedas an alternative to straddle car-rier systems. Gaussin describesstraddle carriers as the most ex-pensive and most costly to oper-ate and maintain type of groundhandling equipment.

A straddle carrier, of course,grounds the container at the quayand is itself the grounding/stack-ing machine, and this doubledecoupling ability has traditionallybeen highly rated for its efficiencyand cycle speed. However, there isa body of opinion that, in terms ofthe cycle between ship and stack,the stack interface is where mostdelays occur in RTG terminals.

In a sense, ATT Lift can be seenas the Gaussin equivalent of the

ATT Lift from Gaussin

safeLightweight, durable and energy-efficient: low-friction P4 rol e-chainsystems® for 57% less driveenergy consumption + Easy to install and corrosion-free modular aluminium-guide troughs forless system weight + High-speed data transmission with rugged chainflex® fibre optic cables +Easy PPDS 2.0 condition monitoring system for push-pull forces to prevent downtime.

safe power...safe data...safe operation...save money

Visit us: Asia, Hong Kong - Booth E26

-cranes.complastics for longer life®

igus® GmbHSpicher Str. 1a

D-51147 Colognecranes@igus.com

phone +49-2203-9649-0fax +49-2203-9649-222

Austria +43-7675-40 05-0Belgium +32-16-314431Brazil +55-11-35314487Canada +1-905-7608448China +86-21-51303100Denmark +45-86-603373

France +33-1-49840404Great-Britain+44-1604-677240India +91-80-39127800Italy +39-039-5906-1Japan +81-3-58192030Malaysia +603-7880 5475

Mexico +52-728-284-3185Netherlands +31-346-353932Poland +48-22-8635770Portugal +351-22-6109000Singapore +65-64871411South Africa +27-11-312-1848

South Korea+82-32-8212911Spain +34-936-473 950Sweden +46-42-329270Switzerland +41-62-3889797Taiwan +886-4-23581000USA +1-401-4382200

save

EU-878-Cranes 178x254M_EU-878-Cranes 178x254 07.05.12 12:35 Seite 1

30_WCN_Jan_2013.indd 1 11/02/2013 15:56:30