Two new purpose-built offshore service operations vessels were officially put into service this week.
The Esvagt Froude and Esvagt Faraday are the first dedicated offshore wind service operations vessel of their kind, providing accommodation for up to 40 technicians, storage for small turbine parts and a workshop, and personnel transfer capabilities in up to 2.5 metre significant wave height. They include a Safe Transfer Boat (STB) 12 and smaller STB 7 vessel for transfer to turbines, as well as an Ampelmann walk-to-work system that compensates for wave motion.
The twin vessels, the Esvagt Froude and Esvagt Faraday are already fully committed to a wind project each, and are chartered by Siemens to support their servicing contracts of the wind projects. Both Baltic II and Butendiek have 80 Siemens 3.6MW turbines, and are sited far enough from shore to make daily trips for the technicians uneconomical. The vessels can stay at the site for periods of two weeks to a month. Siemens has a servicing contract of five years at Baltic II, owned by EnBW and ten years at Butendiek, owned by Wpd.
The 83.7-metre long vessels were designed by Siemens and Esvagt, a vessel company with experience in the oil and gas industry, and in crew transfer vessels. They are identical other than providing different heights for the Ampelmann transfer system – one at 10.5-metres height and the other at 22.5-metres, in accordance with the seas in which they operate.
By staying on site and increasing the availability of technicians to the wind turbine, productivity of the project could increase by as much as 50%, said Mark Albenze, CEO of Siemens Service Wind Power and Renewables.
EnBW, owner of Baltic I and II, a far-from-shore site, was looking for a solution to cost-effective maintenance: "For Baltic I, we use land based service with a service centre near the harbour," said Michael Boll, head of offshore wind operations at EnBW. The transfer time to Baltic I takes 1 hour 15 minutes, but for Baltic II, the transfer time is more than three hours, he said. "We had to find a solution, considering travel, the number of technicians, access and reliability."
EnBW decided against using helicopters as a solution, largely because they were unable to transfer enough personnel, he added.
The SOV vessels are being hailed as the new solution to offshore maintenance. With input into the design from turbine owner, vessel supplier and wind farm owner, and delivering the latest digital analytics, fast response time to turbine failures, and the care and welfare of technicians, it is hoped that they will provide maintenance regimes that will increase the operation of the offshore wind farm.
The Ampelmann walk-to-work sited on the deck of the vessels
The onboard workshop
Indoor facilities for the technicians