Cables are the main culprit of damage to windfarms. Much is unclear about causes and responsibilities. This is the reason why insurers remain hesitant to insure windfarms and market parties prefer to keep detailed information on this subject to themselves. Can cable monitoring provide solace?
During the construction of an offshore windfarm, cable costs account for only 10%. However, they also account for 40% of damage claims and even 85% of damage costs, according to insurance company Delta Lloyd, one of the three largest insurers of windfarms in Europe.
In 2017, there were at least seven cable repair projects in the North Sea and the Baltic Sea, says Mr Wouter de Zeeuw, Lead Engineer at ECE Offshore, a statement garnered from media reports and the company’s four to five engineering assignments. According to Willem Schrijver, the number of claims is increasing because more cables are being laid. It is estimated that 1,500km of cable will be installed annually in the next ten to fifteen years, “So, there are more moments when things can go wrong,” says Mr Schrijver. He fears that the price pressure on windfarms will also impact cable quality, although this is not immediately apparent from the figures. In addition, repair costs will increase. “Damages happen unexpectedly,” he says. “A contractor has to repair it as quickly as possible, thereby raising the price.” Specialised vessels and the greater distance to shore reinforce this effect. But then, how big is the damage? Mr Schrijver explains: “Repairs to offshore windfarms cost from 100,000 to 200,000 Euros per day. An entire campaign to repair a failing cable costs between three to eight million Euros. The damage from no electricity being supplied has to be added.”