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Offshore Support Journal

Offshore Support Journal

Shore power and new energy sources will further reduce OSV fuel consumption and emissions

Mon 02 Oct 2017

Shore power and new energy sources will further reduce OSV fuel consumption and emissions
KL Sandefjord is the first offshore vessel with the DNV GL class notation Shore Power

Taking power from shore when in port, or ‘cold ironing’ as it is known, can significantly reduce an offshore vessel’s emissions, as can hybrid propulsion systems with batteries


As highlighted on a number of occasions by OSJ, hybrid battery-based energy storage systems (ESSs) are being installed on a growing number of offshore vessels. Installing an ESS can reduce fuel consumption and emissions when a vessel is at sea, but there are other ways that a ship’s emissions can be reduced – not least when in port, an example being the offshore vessel KL Sandefjord, owned by K Line Offshore AS, a wholly owned subsidiary of Kawasaki Kisen Kaisha Ltd (‘K’ Line), which has become the first offshore vessel with the DNV GL class notation Shore Power.

The Shore Power notation verifies the design and installation of a vessel’s onboard electrical shore connection. When in port, the vessel can shut down its engines and rely on a shore-based electrical supply for its needs at berth.

“We are very pleased to receive this notation for our anchor handler, which reflects our commitment to ensure a cleaner port environment,” said K Line Offshore AS senior vice president, operation and technical, Espen Sørensen.

“With an onboard shore power installation tested and verified by DNV GL, we have an offshore vessel equipped for the future. And as a result of the good co-operation we have enjoyed with the Bergen Port Authority and DNV GL during this process, we have also decided to apply for the Shore Power class notation for a sister vessel, KL Saltfjord.

By tapping into an onshore electrical supply, vessels not only reduce their fuel consumption, they also eliminate associated emissions. This will have a marked improvement on the air quality in the port and surrounding environment, reducing particulates, NOx and SOx and reducing CO2 by using more efficient shore-based electricity.

DNV GL says it anticipates that, in combination with the use of renewable energy sources, shore-based electrical supply to a vessel can even result in zero-emission operation for the duration of a vessel’s stay in port. In addition, it can free the engines for maintenance, reduce wear and tear and limit noise.

“There is an increasing awareness of the impact of shipping emissions in ports, and this is driving investments in cold ironing,” said DNV GL’s senior vice president and regional manager North Europe Jon Rysst.

“This is leading to ports requiring and incentivising the use of alternative maritime power. As access expands, alongside the rise of fully electric and hybrid vessels, cold ironing could soon become standard procedure in many ports around the world – with a noticeable positive impact on air quality. With the Shore Power notation, shipowners can easily document a safe interface between shore facilities and the ship, based on IEC standards.”

DNV GL’s shore connection class rules cover safety requirements for a vessel’s onboard electrical shore connection. The notation ensures a safe and efficient way of undertaking connection and disconnection of shore power. DNV GL also verifies compatibility between ship and port and provides recommendations for a well defined futureproof technical solution.

The technical requirements are based on the international standard for high voltage shore connections established by IEC, ISO and IEEE in the IEC/ISO/IEEE publication 80005-1 Utility connections in Port – Part 1: High Voltage Shore Connection (HVSC) Systems. Part 3 of this standard is currently under development and will deal with low voltage shore connections. DNV GL is actively involved in this work as a member of the IEC working group.

As hybrid propulsion systems with battery energy storage systems take off in the offshore vessel sector, two classification societies, DNV GL and Bureau Veritas, have issued rules for energy storage.

With the offshore vessel industry emerging from recession, it is tempting to think that technical advances have ground to a halt for the time being. They haven’t. As highlighted recently by OSJ, recent weeks have seen Statoil fix term charters for several offshore vessels that will be upgraded with hybrid battery propulsion as a condition of the contract.

All of the vessels in question will be equipped with hybrid battery operation with the possibility for shore power connection. This will allow them to reduce fuel consumption while working in dynamic positioning mode. Four vessels were awarded five-year firm contracts with five further one-year options: Sjoborg (Skansi Offshore), Far Searcher (Solstad Farstad), Skandi Flora and Skandi Mongstad (DOF). Three vessels were awarded three-year firm contracts with three further one-year options: Juanita (Ugland), Havila Charisma and Foresight (Havila Shipping).

Back in 2015 in a special supplement on marine propulsion, OSJ highlighted the fact that batteries in a hybrid arrangement benefits vessels in a number of ways. Hybrid propulsion that combines electric drives, diesel generators and batteries can make offshore vessels more fuel efficient, reducing fuel consumption and CO2 emissions and enhancing the level of redundancy on board. The overall power-generation requirement on a vessel can be reduced by removing a genset, and other gensets can work at their optimum load, reducing wear and tear on them. Batteries also smooth the load by compensating for peaks and troughs, as well as enhancing safety and reliability by providing backup in the event of blackouts.

Now, as the Maritime Battery Forum recently noted, two class societies in the Maritime Battery Forum have rules for energy storage on ships. DNV GL has had energy storage in the rules for some time, and now Bureau Veritas (BV) has released theirs. We shouldn’t forget that Lloyd’s Register has also issued guidance on large battery installations.

“With a growing number of hybrid vessels entering service, Bureau Veritas has recently released a new series of notations and rules addressing the requirements of energy storage systems to support ship operators in reducing emissions,” said BV. The new class notation includes power management, power backup and zero emission standards. It is expected that the notations will encourage wider uptake of energy storage systems.”

As Martial Claudepierre, a business development manager at Bureau Veritas, said “Industry uptake of hybrid and battery technology has been driven by environmental regulation. But owners are also finding performance benefits, and for some operations, significant financial benefits seem likely – particularly as the availability of renewable energy increases.”

OSJ also recently reported on a new service operation vessel for Louis Dreyfus Armateurs with a DC distribution grid from ABB that can incorporate batteries. BV also highlighted the ability of battery-based energy storage systems to provide peak shaving, power smoothing and power for dynamic positioning operations, features especially applicable to OSVs.

The case for batteries has also been made in a lifecycle analysis (LCA) of battery technology completed by the Maritime Battery Forum in co-operation with Grenland Energy and ABB, supported by the Norwegian Business Sector’s NOx Fund. The LCA looked at batteries on a ferry and on an OSV. “The results show a great case for maritime batteries,” said the forum.


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