Saft has been awarded a contract by ABB Marine to supply a specialized high power liquid cooled lithium-ion (Li-ion) Super Phosphate (SLFP) battery system for ABB’s new state-of-the-art diesel-electric hybrid subsea cable-laying vessel. The Saft batteries will deliver effective energy storage for backup in cable loading and propulsion assistance, helping to cut the vessel’s fuel consumption by 27 percent and reducing maintenance compared with traditional AC systems.
ABB High Voltage Cables has ordered the advanced cable-laying vessel to boost the capacity of its submarine cable operations to perform AC, DC and fiber optic cable-laying and repair anywhere in the world while achieving greater efficiency and precision. The SALT 306 CLV-design vessel, which is believed to be the biggest of its type in the world, will measure approximately 140 by 30 meters. It is being custom-built to ABB specifications at Kleven shipyard in Norway. Delivery is expected in 2017.
The vessel’s diesel-electric propulsion system will be powered by six high-speed Caterpillar 3516 propulsion engines (with around 2 MW of power each) acting as gensets for three Azipod CZ980 thrusters of 1,900 kW. The thrusters, each with a thrust of more than 34 tonnes, will enable DP3 operations. Power will be converted into electricity through ABB Marine’s Onboard DC Grid, which enables variable speed running to optimize engine operations.
The 70 kWh capacity Saft battery system will be used mainly to assist the outloading of cable from the dock onto the vessel’s turntables. These operations will be primarily powered by a shore to ship cable, since the vessel’s diesel engines must be switched off when docked to meet new emissions regulations. However, should this supply be interrupted the battery can support a peak load of up to 800 kW for 10 seconds, which is sufficient to bring the turntables to a safe, controlled stop.
When at sea, the battery system can also be used for peak shaving, when there is a temporary surge in demand for propulsion power and enhanced dynamic response, when propulsion power needs to be increased rapidly.
The ABB cable-laying vessel is the first in the world to be fitted with Saft’s new generation marine battery system featuring Li-ion Super Phosphate (SLFP) cylindrical cell technology with liquid cooling. This approach offers significant advantages over other air cooled Li-ion technologies in high power applications including: a wider operating temperature range; higher cycling capability; better battery level temperature control; improved abuse tolerance; better safety compared to other Li-ion chemistries.
The SLFP cells and battery system for the ABB cable-laying vessel will be developed and manufactured at Saft’s factories in France. Delivery is scheduled for Q4 2016.