One of a growing number of service operation vessels ordered in recent months, Louis Dreyfus Armateurs’ newbuild combines a high level of operability, low operating costs and logistics innovations
Designed by Salt Ship Design in Norway and to be built by Cemre Shipyard in Turkey, Louis Dreyfus Armateurs’ (LDA’s) new service operation vessel (SOV) is the subject of a long-term contract with Dong Energy. It will operate on four offshore windfarms off the German coast – Borkum Riffgrund 1 and 2 and Gode Wind 1 and 2 – providing a base for windfarm technicians.
Due to be delivered by the Turkish yard in the fourth quarter of 2018, the 83.0 m vessel has a beam of 19.4 m and will be equipped with a dynamic motion compensated gangway with what Salt Ship Design describes as “a unique onboard logistic solution”.
LDA worked closely with Salt Ship Design to develop a vessel tailored for the needs of the offshore wind industry. “This has resulted in a very purpose-driven SOV,” said the Norwegian naval architect.
“LDA is expanding its range of services in the renewables industry. Its personnel have been working closely with us for a long time to develop a vessel tailored to meet the needs of the offshore wind industry,” a spokesperson for Salt Ship Design said, “in particular, focusing on enhanced operability and efficient logistics. The contract is an important milestone for us because the renewables industry is becoming an increasingly important market.”
The ship will have accommodation for a minimum of 60 windfarm technicians and will provide them with comfortable conditions, including individual cabins, a gym and a cinema. The technicians will be transferred to the wind turbines via a specially designed daughter craft (in case of good weather conditions) and will use the motion compensated gangway in heavy seas. The daughter craft will be capable of transferring eight windfarm technicians and 1 tonne of cargo to a turbine. The motion compensated gangway will have a range of approximately 19 m and will be complemented by a unique motion compensated crane with a lifting capacity of 1 tonne at 23 m.
LDA has opted for the construction of a highly specified vessel that combines a number of innovative ideas, not least in terms of its environmental impact and operating costs, which will both be reduced as a result of the adoption of a hybrid diesel-electric propulsion system combining diesel engines and batteries.
The windfarm service vessel will have a DC power distribution grid that will allow batteries to be integrated into it, making the ship more environmentally friendly and efficient. ABB is installing the DC grid along with what it calls a power and energy management system enabling the generators to run at variable speeds while also charging the batteries.
In a statement about the system , ABB marine and ports global product manager for Onboard DC Grid John Olav Lindtjørn said “Energy storage can be used for many purposes onboard. Sometimes it serves as the sole energy source, but for this windfarm vessel, it is being deployed as an effective supporting element for the main engine.”
The DC grid will integrate two sets of batteries that will be used primarily for spinning reserve and peak shaving so that power peaks during operation can be covered by the battery rather than starting another engine. Battery power can also act as backup for running generators, reducing the need to run spare generator capacity.
The level of operating efficiency available in a hybrid power system reduces wear and tear on engines and significantly increases fuel efficiency at lower loads where, in traditional AC power systems, generators run at a fixed maximum speed regardless of the power demand on board.
Apart from enhancing the ship’s green credentials in the environmentally conscious offshore wind industry, ABB also points to a benefit for the vessel’s crew: reduced vibration when the hybrid system is on battery power.
ABB marine and ports managing director Juha Koskela said “Shipping is waking up to the many advantages of energy storage. With the industry starting to use batteries more and more and fuel cells becoming a viable option, we fully expect the Onboard DC Grid to gain further traction.”
MAN will supply the 8L21/31 variable-speed gensets for the vessel, which will also feature the company's EPROX energy saving electric propulsion system, which will furthrr reduce the vessel’s fuel consumption and emissions. The engines will be prepared for IMO Tier III and set up in such a way that they can be retrofitted at a later date with an SCR system. This is to cater for the possibility that IMO Tier III NOx emission limits could be introduced, without obligation, in NOx emission-control areas in the North and Baltic.
Uptime in Norway will supply the walk-to-work gangway for the LDA newbuild. TTS Group and Ulstein will provide the motion compensated crane. Together, the companies have been awarded a contract for a TTS Colibri motion compensated crane for the SOV. The new crane combines TTS’s expertise in crane design and manufacturing with Ulstein’s expertise in motion technology and analysis.
“Two features make the TTS Colibri unique compared to other solutions in the market,” claimed Gilbert Rezette, managing director of Ulstein Equipment, a Dutch subsidiary of Ulstein Group. “Firstly, the Colibri system is a stand-alone add-on device for a standard offshore crane. It adds functionality, while the crane maintains its functionality as a full-fledged offshore crane including deepwater subsea capabilities. However, what makes this system truly unique is its groundbreaking anti-sway technology, which also allows it to mitigate wind-induced motions that act directly on the load.
“3D motion compensation technology is not new to the industry and has enabled greater operability for personnel transfer between vessels and fixed offshore platforms through the use of motion compensated gangways,” he said. “However, operations typically require personnel and equipment to be transferred between a vessel and platform. Hence, TTS Colibri is a natural step in enhanced vessel operability, providing motion compensated lifting to match the increased operability offered by motion compensated gangways.”
“Joining forces has enabled both our companies to offer a serious and commercially very attractive alternative in this market segment,” said Carl Herland, sales manager at TTS Offshore Solutions, a subsidiary of TTS Group. “Colibri is suitable for retrofit to existing cranes, making it a viable solution for upgrading cranes that are already in service. Hence, it offers shipowners the ability to enhance the flexibility of their existing fleet.”