New vessel type from ESVAGT purpose-built for wind farms far out to sea

In recent years, Esbjerg-based ESVAGT has focused on designing vessels for servicing large offshore wind farms located far out to sea. This work is now culminating with the deployment of a new vessel and a brand new contract with MHI Vestas to design another one. The prospects for the so-called SOVs are good, also in the long term, according to ESVAGT. 

Off the Belgian coast lies the Belwind 1 wind farm, where MHI Vestas has supplied the 55 3 MW wind turbines that make up the wind farm’s 165 MW production capacity. ESVAGT has serviced the Belwind 1 wind farm with the vessel ESVAGT Supporter for six years.

A brand new vessel will soon take over the job. ESVAGT has developed a new SOV, designed specifically for the Belwind wind farm. This is the latest SOV vessel from ESVAGT, which now has five different vessels purpose-built for the wind farms they operate in.

One of the first vessels ESVAGT developed was ESVAGT Faraday, which sails out from the Port of Esbjerg to the Butendiek wind farm located some two hours from shore.

SOV stands for Service Operation Vessel, and these vessels are different from the Crew Transfer Vessels (CTVs) typically used by the industry. The SOV vessels can remain at sea for up to 28 days, whereas the CTVs are deployed for one day at a time. This offers much greater flexibility in the level of service provided by the personnel on board, explains Ole Ditlev Nielsen, Chief Development Manager at ESVAGT.

“With the SOVs, personnel no longer need to be transported back and forth every day. They stay at sea and have only a 15-minute transfer to and from the wind turbines. This allows for a more agile operation, where they can react as required without having to return to shore to pick up spare parts, for instance,” he says.

More and more offshore wind farms are being built farther from shore, which increases the transport time for the personnel working on the wind farms. According to Mr Nielsen, this is what has created the need for the SOV concept.

At the Port of Esbjerg, Sales Manager Jesper Bank recognises this trend. More large-scale wind farms located far offshore has boosted the development of service concepts for the offshore wind industry.

“To begin with, we mostly just received the smaller CTVs. Today, we see more and more SOVs, which are bigger and remain at sea for longer stretches of time. I believe the trend towards new, larger and more flexible vessel types will continue, and as a port we are ready to adapt our facilities, quays and services accordingly,” he says.

New requirements – new services

From its head office at the Port of Esbjerg, ESVAGT controls its offshore activities, including the development of the new SOV. 

The collaboration with Belgian Belwind 1 began in 2010, and the company has since had an ongoing dialogue with MHI VESTAS about their requirements for the wind farm. The new vessel, H-048, is purpose-built to meet some of the requirements they have jointly identified over the years. Among other things, this means that H-048 is smaller and carries fewer personnel, explains Mr Nielsen.

“With H-048, we eliminated the gangway system, as it made no sense for this particular wind farm. This means we only have boats, so technicians are conveyed to the turbines in smaller transfer boats, which makes the vessel considerably smaller,” he says.

The larger SOV vessels can accommodate 40 technicians, while the new and smaller vessel has room for 22. H-048 is 58.5 metres long and was launched on 21 June 2017 at the Cemre Shipyard in Turkey. The vessel is scheduled for deployment in the autumn after sea trials.

Like the existing SOVs, ESVAGT has developed the new vessel in collaboration with Norwegian Havyard Ship Technology. 

ESVAGT's new SOV, H-048, is the first of the Havyard 831 SOV Design.

New collaboration on Deutsche Bucht

ESVAGT’s next development project is already in place. Earlier this year, they signed a contract – also with MHI Vestas – to design a SOV for the new Deutsche Bucht wind farm being developed by Northland Power, Inc. 95 km off the Germany Bight in the south-east part of the North Sea.

The wind farm is located far from shore and is thus another example of why it makes sense to develop a SOV that can service the wind farm for extended periods without having to return to shore. Unlike H-048, the new vessel will have a gangway so the personnel can access the turbines directly from the vessel. The gangway enables operations in weather conditions that are too rough for ESVAGT's Safe Transfer Boats.

Although the SOVs are more expensive than the smaller CTV vessels, ESVAGT believes they are worth the investment, explains Mr Nielsen:

“If a wind farm like Deutsche Bucht is out of service, it will cost up to an estimated EUR 8,000 a day. It is therefore a major advantage to be able to provide maintenance and repairs continuously without having to go back and forth to harbour. Most of the large wind farms located far offshore are intended to operate for 20-25 years, so we believe a SOV vessel will be a profitable investment for clients, because they avoid inefficiencies in connection with maintenance and servicing,” he says.

Once the SOV has been developed, it can service wind farms for many years to come. H-048 will be working in the Belwind 1 wind farm for the next ten years, while the new contract with MHI Vestas regarding Deutsche Bucht is for a term of 15 years.

Bright prospects for the future

Deutsche Bucht will be completed in 2019, and ESVAGT also expects to have the new vessel launched, tested and ready for deployment by then.

ESVAGT hopes that the future will hold orders for more purpose-built vessels. If the trend of offshore wind farms moving farther out to sea continues, Mr Nielsen expects the development of SOVs and purpose-built vessels could accelerate further.

Moreover, the general conditions in the wind industry currently indicate there are good development opportunities, he says:

“The decline in oil prices in recent years has led to cost cutting and restructuring within the oil industry, which leaves less room for development. However, the situation in the wind industry is somewhat different. New projects are being launched all the time, and things are moving fast at the moment. Therefore it makes even more sense for ESVAGT to pursue this path,” says Mr Nielsen.

ESVAGT today has 900 employees, the majority at the head office in Esbjerg, where the company’s administration, development and warehouse facilities are also located. 

About Service Operation Vessels (SOVs)

Since 2010, ESVAGT has provided services to offshore wind farms using purpose-built Service Operation Vessels (SOVs) accommodating the client’s technicians. In addition to cabins and leisure facilities, SOVs are equipped with office and meeting facilities, spare part storage and workshops. Technicians, spare parts and tools are transferred to the turbines via Walk-to-Work gangway systems or Safe Transfer Boats.

H-048 is the fifth SOV vessel developed by ESVAGT. The four others are ESVAGT Faraday, ESVAGT Njord, ESVAGT Supporter and ESVAGT Froude. H-048 stands out by being the first vessel of the Havyard 831 SOV design, which means that the vessel is smaller and can accommodate fewer people. The other four are of the type Havyard 832 SOV.

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