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Thursday, September 17, 2020 

Norwegian Electric Systems (NES) and Faroese shipowner Skansi Offshore have published operational details of the energy storage system to PSV vessel 'Sjoborg', currently on a five year contract with Equinor, operating in the North Sea based in Flor on the North-West part of Norway.

The vessel is equipped with a diesel electric propulsion system, in addition to an automation system and bridge design from NES. In 2018 the vessel was retrofitted with a Quest Energy Storage system with a 565kwh battery pack and a 1500 kW micro-grid connection to the existing AC MSB , in order to meet requirements from the tender issued by Equinor - obtaining Battery Power notation from Class. NES was responsible for system integration and delivery of the Battery container in addition to other necessary integration and software update on IAS/PMS and switchboards.

The PSV operates as much as 30% in DP mode supporting offshore platforms. In this mode the vessel benefits most from the battery system, with about 20% reduction in fuel consumption. Operating the switchboard with a close bus tie, and reducing the number of engines running, the battery system ensures reduced emissions but also reduced cost for the charterer. The size of the battery system is dimensioned with a safety aspect ensuring that the vessel can abort a DP-operation and move into a safe zone outside the platform within 15 minutes.

During calm weather condition, while in standby mode, the use of the battery-system also reduces the fuel consumption, due to only one required diesel generator running. In addition the battery system can be used when the vessel is in harbour, either self-supplied or in combination with shore power if available. As an example Sjoborg used 2.2 – 2.4 m3/day in fuel before the retrofit. After the retrofit with batteries, the consumption is 1.6-1.8 m3/day, according to Johan Sigurd Fjallsá, Technical Manager, Skansi Offshore.

An important aspect is the reduced maintenance cost; it is anticipated that the Owner will save some €15,000-20,000 per year, and the regular yearly maintenance work can be postponed due to decreased running hours.

Optimising the system, through feedback from Owner, understanding the operational profiles and optimising the software has been important for NES. According to General Manager Sales, NES , Svein Ove Farstad, the dialogue between owner and NES during the past two years has enabled both parties to enjoy seeing the new technology implemented, contributing to reduced emissions and increased knowledge about hybrid solutions,

NES sees an increased demand for greener solutions for offshore vessels. It is  working with battery technology in many segments, and gaining experience from systems that have been in operation for several years. The company aims to offer a customised system for each vessel, understanding the importance to deliver competitive solutions for the owner.

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