The new hybrid vessel is under construction in Japan. It will be 70 meters in length, have a capacity of 499 gross tons and the cargo will mainly consist of steel materials.
“This vessel has been approved for funding through a government program to reduce emissions and save energy in coastal shipping. Efficiency is therefore very important in this project. The hybrid propulsion system we are supplying is based on a Multidrive from ABB,” says a spokesperson for Nishishiba Electric Company, a system integrator headquartered in Himeji, around 500 kilometers west of Tokyo.
Compact liquid-cooled Multidrive
ABB ACS880LC Multidrive supplied for the vessel has three inverters, one for each of the two propulsion motors and the thruster. Extremely efficient liquid-cooling makes the Multidrive very compact, enabling it to fit in the restricted space in the vessel. ACS880 liquid-cooled Multidrives are well-suited to marine conditions with coated circuit boards, an extended operational temperature range and a totally enclosed cabinet, and they are designed to withstand vibrations on board.
The vessel’s Multidrive includes two DC feeder units (DFUs) and two Optimal grid convertersTM for hotel loads. The DFUs enable energy storage or sources – such as supercapacitors or, as in this case, batteries - to be connected to the drive system’s common DC bus. Energy can be transferred from the bus into the batteries, and discharged back from the batteries to the bus. This allows the vessel to operate on battery power with zero emissions.
“We developed the DFU in response to demands from the marine industry – it’s specifically designed for use on hybrid or full electric vessels and has a very small footprint,” says Jarkko Mattila, Global Product Manager, ABB. “DFUs are typically used for heave compensation, peak load compensation or propulsion.”
The drive system’s Optimal grid convertersTM utilize the DC voltage of the ACS880 liquid-cooled Multidrive and convert it to AC at a stable voltage and frequency. This is used to power the vessel’s hotel load, i.e. non-propulsion applications like navigation equipment, pumps, fans and lights.
ABB Multidrives enable flexible and efficient energy transmission in varying load conditions, as well as peak shaving. The operator can therefore minimize fuel consumption, reduce maintenance costs and run emission-free when needed to cut local air pollution.
ACS880 liquid-cooled Multidrives also offer a shore connection, which is becoming increasingly important in view of emissions reduction targets in ports. The vessel can use the shore connection to connect to the port’s power grid. This not only enables it to meet fuel saving and zero emission targets, but also reduces engine noise and vibration.
Energy efficiency and flexibility
Hybrid propulsion systems and electrification are very much in focus at present, as tightening emissions regulations shift the marine industry towards environmentally friendly and energy efficient shipping. The primary concern is to reduce energy usage, as well as eliminate emissions and noise pollution in ports.
The on-board energy mix is changing to meet emissions targets, but it is not yet clear which energy sources will become dominant in the medium-term future. In this situation electric power transmission systems are a future-proof and flexible choice.
Technical collaboration and certification support
The rapid growth of electrification means the marine industry is going through a period of major transformation. ABB’s specialized marine engineering team supports customers faced with the need to embrace new technologies.
“Our engineers collaborated closely with Nishishiba’s team from the outset,” Jarkko Mattila explains. “We shared our expertise in marine DC grid applications, provided system-level support, and held extensive discussions on various technical aspects of the system. Working together in a joint effort, we produced an optimally efficient solution for the shipowner. Our cooperation with Nishishiba went very smoothly – it was a pleasure to work with such a professional system integrator.”
Additionally, one of the ABB experts worked with the certification body, Nippon Kaiji Kyokai (ClassNK), to ensure that the ACS880LC Multidrive could be certified to the appropriate marine standard.
The hybrid vessel is due to be launched in April 2023. It will help to reduce emissions from Japan’s coastal shipping industry, which plays an important part in the nation’s freight transport system.