According to Jayesh Vir, batteries are powering new trends in electric and hybrid marine propulsion

Electric and hybrid propulsion is on the rise as the maritime industry strives to meet the Marpol target to reduce greenhouse gas emissions by 30 per cent by 2025. A combination of electric drives, diesel generators and high-power batteries are giving rise to hybrid propulsion schemes, creating a new breed of vessel power management systems. These systems have been created with reducing fuel consumption, CO2 emissions and overall maintenance in mind. At the heart of electric and hybrid propulsion is a battery system, which when added to each engine or more globally – to the overall power distribution network, brings new benefits.

The benefits of hybrid propulsion include the capability to downsize total power generation of gensets by removing one unit, while others can be loaded at their optimum working range. The batteries boost power to meet peak demand when needed. This also helps in load smoothing as batteries can absorb the peaks and troughs. Additionally, batteries also enhance safety and reliability by providing backup in the event of a blackout.

When it comes to batteries, they can be made up of multiple chemistries depending on the application. Lithium-ion is a broad term and in the case of hybrid propulsion, the choice of battery technology is critical to success. Saft’s Li-Super-Phosphate (SLFP) high-power and high-energy cell technology is currently leading the way, with Bureau Veritas, Lloyds Register and DNV GL certification.

SLFP technology can be tailored for a range of battery requirements as it is modular, so can be tailored to closely match the customer’s power and voltage outputs. SLFP is providing a great opportunity for further civil marine applications and developments with benefits like a high inherent level of safety, reliable performance delivered over a wide temperature range and a high tolerance to electrical and mechanical abuse. SLFP also has the advantages of long calendar and cycling life, high power output, high efficiency and fast charge ability and is incorporated in Saft’s Seanergy systems.

Benefits of SLFP technology on the MV Catriona ferry
One vessel which has incorporated SLFP technology is the MV Catriona ferry, the third hybrid Roll On Roll Off (RORO) passenger and vehicle ferry designed for use on Scotland’s short sea crossing route around the Clyde and Hebrides. RH Marine has installed two Seanergy systems on board this vessel, which has the ability to provide a total of 800 kWh of energy storage. This means that the vessel can be powered in battery mode only and in hybrid mode in combination with a diesel generator. While the ferry is in port, the batteries are charged overnight from shore supply, ensuring that there is always enough power to transport the maximum that the vessel can carry – 150 passengers and 23 cars or two HGVs – at a service speed of nine knots.

SLFP powers the polar research vessel Sir David Attenborough through the thickest ice
One of the most advanced vessels of its kind, the Sir David Attenborough has been commissioned by the UK’s Natural Environment Research Council (NERC) for operation by the British Antarctic Survey. The vessel has to face some very extreme conditions, including pushing through ice up to one metre thick, while towing equipment over the side, with tremendously low underwater radiated noise. This is to ensure that no marine mammals and fish shoals are disturbed and that there is no interference with survey equipment.

In order to do this, it’s important to have reliable batteries to help power the diesel electric propulsion system. New Bergen B33:45 engines are behind the diesel propulsion, in combination with two specialised Seanergy battery systems, integrated by Rolls-Royce Marine. These batteries have been sized to ensure the vessel is selfsufficient in fuel during voyages of up to 19,000 nautical miles.

The two Li-ion batteries are fully integrated into the vessel’s control and automation system and provide a combined 1450 kWh capacity with a maximum voltage of 1011 V. The batteries have a number of roles, including helping to deliver the peak power required by the vessel, such as when operating in a dynamic positioning mode.

SLFP technology is also beneficial to mega yachts
SLFP technology is also beneficial on a different scale, as it forms part of an innovative propulsion system for Project Zoza. This is the working name for the mega yacht under construction by Benetti in Livorno, Italy. Two battery systems with a total capacity of three MWh will be featured on the private hybrid luxury yacht as part of an electrical power plant, alongside six main engines.

The batteries will help Project Zoza – one of the largest and most advanced private hybrid luxury yachts in the world in various ways, including silent propulsion, peak shaving and zero emission operation in harbour – meaning that Project Zoza is one of the first yachts in the world with this capability.

Jayesh Vir is Saft’s Account Manager for the Marine Segment. Saft specialises in advanced technology battery solutions for industry, from the design and development to the production, customisation and service provision. For nearly 100 years, Saft’s longerlasting batteries and systems have provided critical safety applications, back-up power and propulsion for our customers.