Page 44: of Marine News Magazine (May 2019)

Inland Waterways

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Energy Storage Life

Cycle Cost Study

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.

By Joshua Slade Sebastian, P.E.

his case study provides ef? cient engine loading to increase the overall ef? ciency of the a cost bene? t analysis vessels. With those system improvements, operators will ex-

Tof an energy storage perience an overall reduction in engine hours, fuel consump- system for a vessel owner us- tion, and maintenance costs while improving the responsive- ing a real-world operational ness and reliability of the vessel’s propulsion system. These pro? le and case study. It is not a deep dive into all of the bene? ts can be realized with a variety of propulsion systems, aspects and details of an energy storage system. There are including both Z-drives and conventional shafted propellers. many con? gurations and options available to ? t a wide va- riety of requirements. Naval architects can work with the systems engineers for these manufacturers to determine the

DIESEL ELECTRIC WITH ENERGY STORAGE best system for a particular application.

A Diesel Electric with Energy Storage (DE/ES) system operates by having the batteries provide power to the grid

TYPICAL BENEFITS OF at all times. With the batteries controlling the power grid, the power management system (PMS) monitors the state


For typical marine applications, the use of Lithium Ion of charge on the batteries, discharge rate, and demand batteries (Li-ion) will add spinning reserve, peak shaving, and 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 re- sponse so the DE/ES system can de- liver power even faster than mechani- cal propulsion systems.

May 2019 44 MN

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