Feature 1 | TUGS


Figure 10: On- demand increase of battery capacity


competitiveness and who desire to future-proof their assets are advised to further analyse the impact of the energy transition. Although its exact path is uncertain, the transition towards a zero-carbon economy is irreversible. To avoid suffering impairment losses and/ or costly conversions of conventional newbuilds, continuing to do ‘business as usual’ will no longer suffice. Drastic GHG emission reduction


prepared and flexible to adapt to a


changing environment, while being able to retain value during their 25+ years economic life. Diesel-electric tugs with energy


storage offer this flexibility since they can transform MDO, MGO and future cleaner fuels into electricity while they can also operate on stored renewable electricity. Since energy storage has its limitations it is expected that generators will not be replaced by batteries any time soon, but they can complement each other. Figure 10 simplifies how energy storage can gradually be introduced on an ‘as-needed’ basis. Diesel-electric propulsion is


very mature, and its advantages are demonstrated year-in/year-out by cruise ships, icebreakers, ferries and chemical tankers. It is also the standard for offshore DP vessels (such as PSVs) which have variable operational profiles, as have tugs. The permanent de-coupling of main


engines from thrusters allows for a number of refinement steps, resulting in lower energy consumption, improved ship-handling,


Cost implications Obviously, mechanical diesel-direct-driven tugs are cheaper to build than hybrid/ battery-powered tugs, but what will they be worth aſter five or 10 years from now, when strict emission regulations come into force? A better question would be: “How can we ensure that newly built tugs retain their value over their 25+ years lifespan?” Te answer lies in energy efficiency and resilience. Return on investment of hybrid systems


used to drive decision-making, but meeting GHG emission regulations will soon dictate them for getting the jobs in the first place. Te new driver will become energy efficiency, since tugs which need 2,000kWh ESS are obviously more competitive than those which need 3,000kWh ESS to do the same job. Some ports and terminals have already


included environmental incentives in their tender and license criteria for towage services. Others simply specify that preference is given to those who deliver the cleanest tugs. Te EDDY 24 and EDDY 30 models have


improved reliability


and safety, reduced maintenance and increased crew comfort. Electrification matches with zero-carbon


goals. Electrification also matches with the irreversible trends of automation and digitalisation. Renewable electricity is increasingly price-competitive. Electricity can be made out of ‘anything’ and thus will always be available. Embracing electrification thus provides the foundation for a stable and predictable business case without having to worry about emission regulation compliance. We strongly believe that the future of


tugs is electric and that energy storage will be part of the solution.


26


demonstrated that it is possible to build diesel-direct/diesel-electric hybrid tugs for similar capital cost as conventional diesel- direct tugs of the same performance. Tis is, amongst other factors, due to simplified construction (requiring less steel and fewer man hours) and reduced part count. They are also cheaper to operate. The EDDY-X takes this philosophy one step further, which makes this crossover tug competitive to build and operate under the most stringent GHG emission regulations. There is no need to invest in batteries upfront: they can be added gradually and flexibly as the need arises.


Concluding remarks Tug owners (and shipyards) who are concerned about their long-term


requires a 90degs mindset shiſt, combining energy efficiency with electrification. Te trick is to invest in intrinsically energy- efficient tugs which have the flexibility to accommodate whatever fuels and energy storage technologies emerge, which reduce operational cost and which have lower capital cost than other GHG-emission- compliant tugs. SBI


FURTHER READING Lloyd’s Register/UMAS, Zero-Emission Vessels by 2030. How do we get there?, 2017 (info.lr.org/zev2030, 2017)


DNV GL, Maritime Forecast to 2050 - Energy Transition Outlook 2018


Lloyd’s Register, Low Carbon Pathways (www.lr.org/lcp2050)


Dr. Andreas Schröter, Electrification Driven by Digitalization and New Technology, DNV GL, October 2017


International Chamber of Shipping, Reducing CO2 Emissions to Zero: The ‘Paris Agreement for Shipping’, 2018 (http://www.ics-shipping.org/docs/ default-source/resources/reducing-co2- emissions-to-zero-the-paris-agreement- for-shipping.pdf?sfvrsn=7)


DNV GL, In Focus-Te Future is Hybrid- a guide to use of batteries in shipping, 2015 (https://issuu.com/dnvgl/docs/ in_focus-the_future_is_hybrid)


DNV GL, Alternative Fuels and Technologies for Greener Shipping, 2018


About the author: Capt. Baldo Dielen, BSc, MSc, is a Brazil-based, Dutch naval architect and entrepreneur with 27 years of professional maritime experience. He started developing the EDDY tug concept a decade ago, has tested many prototypes and full-scale tugs, patented the concept and future- proofed the design. He can be contacted at baldo@eddytug.com


Ship & Boat International November/December 2018


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