Energy Storage

  • Diesel electric propulsion is a concept that uses an electrical power generation plant to deliver power to the propulsion unit. Case studies show reductions in fuel and maintenance costs with such systems. Those improvements can be further enhanced by the addition of an energy storage system to the vessel.

    This case study provides a cost benefit analysis of an energy storage system for a vessel owner using a real-world operational profile and case study. It is not a deep dive into all of the aspects and details of an energy storage system. There are many configurations and options available to fit a wide variety of requirements. Naval architects can work with the systems engineers for these manufacturers to determine the best system for a particular application.  

    Typical Benefits of Energy Storage Systems
    For typical marine applications, the use of Lithium Ion batteries (Li-ion) will add spinning reserve, peak shaving, and efficient engine loading to increase the overall efficiency of the vessels. With those system improvements, operators will experience an overall reduction in engine hours, fuel consumption, and maintenance costs while improving the responsiveness and reliability of the vessel’s propulsion system. These benefits can be realized with a variety of propulsion systems, including both Z-drives and conventional shafted propellers.  

    Diesel Electric with Energy Storage
    A Diesel Electric with Energy Storage (DE/ES) system operates by having the batteries provide power to the grid at all times. With the batteries controlling the power grid, the power management system (PMS) monitors the state of charge on the batteries, discharge rate, and demand loads. The PMS then manages the generators to provide appropriate power to the grid to keep the batteries properly charged.  

    The “always online” approach to energy storage provides the best overall system performance.    With this set up, throttle response from the propulsion system can be nearly instantaneous.  The batteries provide the spinning reserve and dynamic response so the DE/ES system can deliver power even faster than mechanical propulsion systems.  

    Hybrid with Energy Storage
    Hybrid with Energy Storage (H/ES) systems make use of a mechanically driven shaft line with a power take off and power take in (PTO/PTI) connected to a motor/generator (M/G) set. The M/G set can take power from the ships electrical system and/or energy storage to provide additional power to the propeller shaft. This system is similar to those in modern hybrid cars. A hybrid system such as this can be especially attractive as a retrofit option for existing vessels.  

    Life Cycle Cost Analysis
    Energy Storage systems should not be considered a one-size-fits-all solution.  As with diesel electric propulsion systems, a careful study of a towboat’s operational profile should be conducted to determine the operational benefits.  Below is a real operational profile used for this case study.  This particular vessel is an 1800HP locking river towboat.

    Vessel: 1800HP Locking River Towboat:
    Some basic assumptions for the life cycle cost analysis include both a 365 day per year operational tempo with a 40-year vessel life cycle.

    There are some minor differences in the systems. First, the total brake horsepower of each system is slightly different. The mechanical system has 1800 BHP while the DE/ES has a maximum of 2000 BHP. Another difference is the mechanical-based design has a total of four engines, with two of those engines being required to be EPA Tier IV, while the electrical propulsion design utilizes only three Tier III generators. The DE/ES system used for these calculations is a DC bus system. The system uses AC generators and AC propulsion motors.  However, the main propulsion bus is DC.  This provides for a smaller, more reliable system and cost-effective solution.

    A DE/ES system does increase the initial capital costs of the towboat. This increase is equal to about $400k increase in overall construction cost of a typical 1800HP towboat.  Most of that increase is due to the costs of the batteries and associated battery equipment.

    Operational Costs (OPEX)
    Operational costs are broken down into two categories: Fuel Costs and Maintenance Costs. For example:

    Fuel Cost: A detailed fuel consumption model was run on the operational profile. TSGI’s algorithm models various battery sizes, generators, mechanical system performance, and mechanical hybrid systems for comparison and optimization.  It uses the actual time data to establish fuel consumption, not an average of engine loads.  This results in a more accurate modeling of fuel consumption and system optimization.  Calculations were compared with actual fuel consumption data for the profile to validate the methodology.

    For these calculations the following assumptions were made:

    • Fuel Cost:  $2.5/gallon
    • Urea Cost: $3/gallon
    • Urea Dosing Rate:5%


    The fuel savings for the DE/ES system is achieved mostly through the functions of peak shaving and efficient engine loading.  By using peak shaving and dynamic response, the overall number of engine hours can be reduced.  This has a large impact on the maintenance costs, as discussed further below.  In this life cycle analysis, the initial capital cost of the DE/ES system is nearly offset in the first year of operations.

    Maintenance Costs:
    Beyond fuel savings, there are significant reductions in cost on maintenance budgets with the use of energy storage systems.  

    Using a DE/ES system for this profile results in a 70% reduction in engine hours over the current mechanical version of the same vessel.  Adding energy storage to a Diesel Electric version also results in a 50% reduction in engine hour.

    Life cycle maintenance costs are based on the engine hours above with a vessel life cycle of 40 years using manufacturers recommended maintenance schedules.

    Beyond Dollars and Cents
    Maritime industries depend on reliable and safe operations. From the smallest towboat to the largest military ship, any vessel without a reliable power plant is a liability. Many of the industries that rely heavily on safe and reliable power, such as ferries and offshore support vessels, have moved to energy storage systems as they represent a significant jump in those areas.  

    While the fuel and maintenance costs are brought down with the use of peak shaving, reliable operation is enhanced with the spinning reserve and dynamic response characteristics of an energy storage solution. In the event of an engine failure, the batteries provide continuous operations while more power is brought online, effectively acting as an uninterrupted power supply (UPS) for the entire vessel.

    Also, such systems can significantly reduce overhaul times. For both the diesel electric and DE/ES systems, replacing a generator performed quicker than replacing a main diesel engine. Depending on an owner’s maintenance program, carrying spare units for a vessel becomes easier as all the generators are the same. Once a unit is removed from a vessel, it can be easily overhauled in a shop without impacting the operational tempo for the vessel.  

    You Have Options
    As with any system or technology, a DE/ES system may not be a viable solution for all vessel owners.  However, this case study shows savings over the life of the vessel can be significant with a properly designed system.

    TSGI recognizes that fuel savings may not return any benefit to the vessel owners depending on contract structure. TSGI expects that the inland market will follow the same pattern that other parts of the marine industry have started to experience, with charterers and commodity owners requesting more fuel efficient vessels instead of just accepting higher fuel surcharges.  

    Joshua Slade Sebastian, P.E., is Engineering Manager at The Shearer Group, Inc. (TSGI). TSGI would like to thank the Marine Division at ABB for assistance with the electrical design of the concept diesel electric towboat and providing some of the technical information for this article.

    This article first appeared in the May 2019 print edition of MarineNews magazine. The original article with all charts and graphs can be found by clicking the link to the magazine to find the e-magazine.

  • new to shipping; the passenger ship sector has been applying diesel-electric propulsion for decades. But recent advances in hybrid-electric power and energy storage technologies are bringing additional benefits. In examining those benefits, it is first important to differentiate between hybrid propulsion and

  • system. Traditionally, a surge chain has been used consisting of one or two shots of very heavy chain. The chain catenary provides the necessary energy storage with the penalty of increased weight and towing resistance and greatly increased catenary depth at low speeds. It is desirable to replace the

  • dynamic-positioning, ACON control and EMS systems.Rolls-Royce RetrofitsIt’s a quiet hybridization that needs some trumpeting, as the benefits of energy storage are key selling points for system integrator and fleet owner.Although moving in different directions — Rolls-Royce Marine losing money of late

  • A primer on the quickly evolving topic of on board battery technology.Energy storage itself is actually old news. Since the sails were taken down for good, merchant vessels have crossed the oceans using some kind of energy safely stored on board. Be it Coal, Diesel, Gasoline or Natural Gas, and regardless

  • North America is increasingly adopting energy storage systems (ESS) to use in combination with combustion engines or as the sole energy carrier in fully electric-powered systems.We clearly see a transition from ‘consideration’ to ‘execution’ of hybrid and all-electric maritime

  • Power and PropulsionThe HybriGen Power and Propulsion system can run free of emissions. Power needs can be fully sustained by the use of battery energy storage.It produces enough power for both the propulsion system and auxiliary hotel loads. With two systems driven by one – it frees up space in

  • of actual marine use. European environmental authority tests of “leading” designs showed they were not. Only Perry’s solution — steeped in decades of energy storage thinking from Western Canada’s lithium battery brain trust — has shown bankable and insurable safety, power management and surplus horsepower.   Indus

  • simple configuration that generates power for the hotel loads by harnessing that power off of the main engine. If we do that income combination with an energy storage system, we can reduce the need for gensets, eliminate extra maintenance, extra fuel burn, and we’re saving costs for the bottom line.(Image:

  • station. Was it ever a concern on what was the size of the gas tank to determine your purchase or model?  Hybrid and EV announces the limit of their energy storage, the first automobiles traveling 150 to 250 miles on a single charge. The latest marketing efforts lead with new 500-mile capability.Marine EV

  • $220 million award, $15.9 million was directed to the Water Emergency Transportation Authority (WETA) for upgrading its ferry floats to include battery energy storage systems. WETA operates throughout the San Francisco Bay, providing critical transbay services and reducing road congestion. Over the last two years

  • Battery based energy storage systems for marine applications are finally moving, cleanly along the global waterfront at full speed. The UN Report on climate change on November 2, 2014, stated that the unregulated use of carbon based fuels must cease by the end of the century. While people can debate the

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    February 2024 - Maritime Reporter and Engineering News page: 40

    also have our ? eet nia than HFO,” said Brindley. “That’s just the weight. When engineering team, which looks at the here and now, making you consider energy density, you need about three times the sure the vessels are as ef? cient as possible. We need to catch quantity of ammonia for an equivalent energy

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    February 2024 - Maritime Reporter and Engineering News page: 39

    to traditional diesel fuel],” said major progress expected in 2024. Räsänen. “You need to be careful on the bunkering location, In July 2023, MAN Energy Solutions announced the successful the size of the bunkering, how you pull your pipes between ? rst running of a test engine [MAN B&W two-stroke

  • MR Feb-24#38  be produced using renewable energy sources,   for a pilot)
    February 2024 - Maritime Reporter and Engineering News page: 38

    treatment. • Renewable Production Potential: “Green” Ammonia While ammonia itself is without carbon, there is the need can be produced using renewable energy sources, for a pilot fuel to start the combustion process. “The engine such as wind or solar power, through electrolysis. manufacturers are looking

  • MR Feb-24#37 , at Yaskawa Environmental Energy / The Switch
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    February 2024 - Maritime Reporter and Engineering News page: 37

    improves ef? ciency by 2-4% compared to synchronous machines." – Dr. Jussi Puranen, Head of Product Line, Electric Machines, at Yaskawa Environmental Energy / The Switch The Switch’s shaft generators start from <1MW and range up to 12MW+. Source: Wärtsilä Source: Aasen Shipping Source: The Switch www

  • MR Feb-24#36  2050. They can test out energy storage and fuel cell 
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    February 2024 - Maritime Reporter and Engineering News page: 36

    Additionally, shipowners can move further towards the and well over 100 in its production pipeline. Most commonly IMO’s 2050. They can test out energy storage and fuel cell to date, orders have been for 174,000cbm LNG carriers. These equipment, he says, and see what bene? ts they provide in vessels

  • MR Feb-24#35  50 tons of equip- lowers their energy consumption and to the)
    February 2024 - Maritime Reporter and Engineering News page: 35

    a shaft generator is not an insigni? - the ef? ciency of modern permanent magnet technology that cant undertaking. Around 50 tons of equip- lowers their energy consumption and to the variable speed ment needs to be installed into the engineroom drives that enable them to provide constant power over a wid- through

  • MR Feb-24#34  on the Rise
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    February 2024 - Maritime Reporter and Engineering News page: 34

    HYBRID Shaft Generators Demand on the Rise Source: MAN Energy Solutions MR #2 (34-44).indd 34 2/6/2024 8:47:46 AM

  • MR Feb-24#29  of changing  ing and enacting energy transition to hit  Also)
    February 2024 - Maritime Reporter and Engineering News page: 29

    . But with the Covid es facing any shipowner today: embrac- that’s just one potential talking point. pandemic and the myriad of changing ing and enacting energy transition to hit Also, there are around 16 different fuel cost dynamics, from raging in? ation to decarbonization targets. options for ships today

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of decarbonization, energy transition and autonomy)
    February 2024 - Maritime Reporter and Engineering News page: 22

    R&D MATT HART Matt Hart, Manager & Platform Leader, Marine & Stationary Power Systems, Wabtec, offers insights on how the megatrends of decarbonization, energy transition and autonomy all inspire Image courtesy Wabtec and impact the marine power solutions from Wabtec. By Greg Trauthwein Matt, to start us

  • MR Feb-24#20  of low and zero emission energy carriers, 
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    February 2024 - Maritime Reporter and Engineering News page: 20

    MARKETS FPSO technology dominates the region’s FPS demand. duction and storage of low and zero emission energy carriers, In all, 18 countries in West and East Africa are expected such as methanol and ammonia. One exciting development to receive new FPSOs, FLNGs and FPUs between 2024 and leverages

  • MR Feb-24#18 MARKETS
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    February 2024 - Maritime Reporter and Engineering News page: 18

    MARKETS Scan the QR Code to Download the Intelatus Floating Production White Paper. Floating Production – A growing segment in transition © AdobeStock_Dolores Harvey The specialized deepwater oil & gas and ? oating offshore wind segments will share many of the same stakeholders and supply chains

  • MR Feb-24#17 METHANOL STORAGE
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    February 2024 - Maritime Reporter and Engineering News page: 17

    METHANOL STORAGE provals from other classi? cation societies are ongoing, said Lilp, – including accommodation.” although he acknowledges that journey from AiP to full class ap- As of September 2023, methanol had been speci? ed for 216 proval is substantive. In an area where the regulations underlying

  • MR Feb-24#16  to prevent corrosion. 
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    February 2024 - Maritime Reporter and Engineering News page: 16

    also creates oxygen-free condi- ton, it takes 2.4 times more methanol to generate the equiva- tions behind the steel plates to prevent corrosion. lent energy as HFO. The SPS sandwich panel system can be used in lieu of coffer- Conventionally, tanks storing low ? ashpoint fuels on board dams on all tank

  • MR Feb-24#13  times, the pandemic and the energy 
crisis, are behind them)
    February 2024 - Maritime Reporter and Engineering News page: 13

    21% falling one spot from the 2023 rankings. While companies may be con? dent that the worst of two key disruptors of recent times, the pandemic and the energy crisis, are behind them. Business disruption remains a key concern as ? rms are challenged to build resilience and diver- sify supply chains in

  • MR Feb-24#12  accel-
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    February 2024 - Maritime Reporter and Engineering News page: 12

    of these batteries has been least 40% by 2030, and 70% by 2050. The IMO’s target is ambitious, and the industry will need to accel- erate its adoption of energy-ef? cient technologies and fuels, such as wind propulsion, biofuels, hydrogen, and ammonia to meet its goal. Political Risks Political risks and

  • MR Feb-24#6  of maritime transport as both  Energy transition and alternative)
    February 2024 - Maritime Reporter and Engineering News page: 6

    to increase globally, and energies take a bite out of the bottom line. Editor - MarineNews Eric Haun the importance of maritime transport as both Energy transition and alternative fuels are [email protected] a global commerce enabler and a bedrock of everywhere. While traditional diesel is still

  • MR Feb-24#4  Learning Systems, maker of  energy and maritime sectors.)
    February 2024 - Maritime Reporter and Engineering News page: 4

    van Hemmen is the President Murray Goldberg is CEO of Ma- gic planning experience in the of Martin & Ottaway, a marine rine Learning Systems, maker of energy and maritime sectors. consulting ? rm that specializes in MarineLMS. the resolution of technical, opera- MacLeod tional and ? nancial issues. Business

  • MR Feb-24#2  of decar-
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    February 2024 - Maritime Reporter and Engineering News page: 2

    Courtesy ARC 22 Marine Power: The Future is Now Departments Matt Hart, Wabtec Corporation, offers insights on how the megatrends of decar- bonization, energy transition and autonomy drive engine innovations. 4 Authors & Contributors By Greg Trauthwein 6 Editorial 8 Training Tips for Ships Addressing Barriers 26

  • MN Feb-24#38   6.2 MWh Orca battery energy storage system from Corvus)
    February 2024 - Marine News page: 38

    mi- grated electrical propulsion package provided by ABB, a crogrid shoreside charging station. The vessel will operate 6.2 MWh Orca battery energy storage system from Corvus with zero emissions while providing the complete perfor- Energy and two electrically driven Schottel RudderPropel- mance capabilitie

  • MN Feb-24#29  been experienced in other energy industries, such as 
coal)
    February 2024 - Marine News page: 29

    .” In terms of cost escalations and other “bumps in the road” for offshore wind, Møller pointed to similar challenges that have been experienced in other energy industries, such as coal and nuclear power. “And if we go back to before the COVID crisis at least, then [offshore wind was] compatible or have

  • MN Feb-24#28  wind still blows “free”, but  energy future. While a handful)
    February 2024 - Marine News page: 28

    have placed an exclamation point on wind is incorporated as a growing part of the United States’ the word “wild”. Yes, the wind still blows “free”, but energy future. While a handful of projects have been de- mounting challenges have proven that harnessing its railed, others continue to push forward with

  • MN Feb-24#20  workforce. 
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    February 2024 - Marine News page: 20

    a cascading impact on nouncing on January 3 that they had reached terms with the U.S. maritime industry and the American workforce. the New York State Energy Research and Development For example, concurrent with the termination of the Em- Authority (NYSERDA) to terminate the Offshore Wind pire Wind 2 OREC

  • MN Feb-24#17   connection of battery energy storage  modate increase power)
    February 2024 - Marine News page: 17

    Emergency Transportation can be mitigated through the inter- sels and upgrade terminals to accom- Authority (WETA) for upgrading connection of battery energy storage modate increase power requirements. its ferry ? oats to include battery en- systems, but there are other signi? cant However, many operators

  • MN Feb-24#16  the Green
By Kaiya Levine, Energy & Sustainability Consultant)
    February 2024 - Marine News page: 16

    Column Going Green For Ferries to Go Green, Governments Will Need to Provide the Green By Kaiya Levine, Energy & Sustainability Consultant, Arup Whether it is from international organizations ? ve nautical miles or less, meaning they have relatively low or state government agencies, there is growing