Siemens Energy has signed a chartering agreement with Danish shipowner Esvagt A/S for the two new 83.7 m offshore wind farn service vessels that the company ordered from Norwegian shipbuilder Havyard last month (see earlier story).

Siemens says the vessels are being commissioned specifically for its service operations at the Butendiek and Baltic II offshore wind power plants in Germany, both of which are scheduled to come online in 2015.

Recognizing the benefits a specialized logistics concept could provide, Siemens has provided input to help in the vessel design and specifications over the last several months. The two highly advanced offshore service operations vessels (SOV) will incorporate the latest in advanced logistics, design and safety for providing service and maintenance at offshore locations, particularly those located very far from shore. The vessels will serve as floating offshore accommodation platforms with spare parts storage and on-site office space.

Rather than using smaller vessels or helicopters to access the turbines, the new vessels will provide direct access using an advanced hydraulic gangway system that will work to stabilize and provide safe "walk to work" access to the turbines at varying wave conditions.

They will provise accommodations for more than 30 technicians for several weeks at a time, enabling them to live and work at the project site and to spend less time traveling to and from shore.

With its ongoing focus on intelligent innovation, Siemens Energy is embarking on this new design concept that, when completed, is poised to be the new standard for offshore wind service.

"With more than 20 years experience in servicing offshore wind turbines, meeting the unique challenges within an often harsh, unpredictable marine environment is our core expertise," said Tim Holt, CEO of Siemens Energy's Service Renewables business. "This new, state-of-the-art design concept has been developed with a strong focus on advancing and streamlining our offshore service operations and logistics for the benefit of our customers. Less time traveling to and from shore allows for more time at the site and a more efficient and cost-effective use of resources. Our charter agreement with Esvagt offers us the opportunity to combine our leadership position with that of an experienced shipping company."

The vessels will be strategically positioned in close proximity to the wind turbines for easier access and more streamlined operations. They will have the ability to stay in the field for several weeks at a time, only needing to return to port for fueling and the replenishment of supplies and equipment. Customers will benefit from Siemens' emphasis on more effective use of resources and personnel, as well as better accessibility with less time lost waiting for a suitable weather window.

Within the framework of providing service for both wind power plants via long-term service agreements, Siemens signed the chartering contract with Esvagt A/S for the use of both service operation vessels.

The construction of the vessels is scheduled to start this month at the Havyard Shipyard in Norway with launch anticipated for early 2015. When completed, each vessel will measure 84 meters in length with a maximum speed of 14 knots.

Both vessels will be built with a continuous main deck and superstructure where the accommodations for the technicians are located. Modern cabins, meeting facilities, an exercise area and entertainment options also contribute to the comfort of the service technicians who will live and work on the vessel. Each vessel will carry spare parts for wind turbine maintenance in standard 20-foot containers on the ship's cargo deck.

Siemens' BlueDrive propulsion system will be used to reduce CO2 emissions and fuel consumption.