Aberdeen’s Subocean Group is showing the way ahead for the renewables industry by becoming the first company to use a dynamically-positioned vessel equipped with ploughing technology to instal cables in a large North Sea windfarm.
The subsea construction company’s innovative approach has cut cable installation time by 50%, providing the marine renewables sector with a more cost-effective and efficient solution. This is straight out of the offshore industry’s book.
Using the specifically adapted cable installation vessel, which represents a £30million investment for Subocean, the company installed four power cables in trenches one metre (just over three feet) deep in 30m (about 100ft) of water on the world’s first 100-turbine offshore farm – Vattenfall’s Thanet project off the Kent.
Subocean secured the £30million contract for this earlier this year.
Two initial cables were installed within 24 hours, which, compared with conventional methods so far used by offshore wind developers, represents a significant timescale reduction in both operational activity and exposure to adverse weather conditions.
The two cables installed are the first of 100 inter-array cables to be embedded within the farm.
Mike Daniel, Subocean’s operations director, said: “This is an important milestone not just for Subocean but for the industry, where resources, including vessels, and expertise are limited.
“To successfully achieve a faster installation and on a high-profile project like the Thanet development is a major step forward in the market.
“The Polar Prince’s capabilities are much more advanced than conventional (lay) barges because it does not require anchors to be run while manoeuvring and the vessel is therefore significantly quicker.
“Traditional barge methods take at least two days to lay and bury one cable, so for Subocean to save a day’s operational activity for one cable is exceptional, particularly when you put it into full project perspective – the Thanet project alone involves laying 100 cables.”
Polar Prince is also better able to withstand hostile weather conditions than barges. During the cable installation on Thanet, it remained on site, even in winds to 60 knots, when other craft were running for shelter.
Subocean provides turnkey project design and implementation, including engineering, procurement, installation and commissioning of subsea facilities. It also supplies offshore management personnel, divers, life-support technicians, ROV (remotely operated vehicle) operators, subsea equipment operators and offshore administrators.