Power-cable failures offshore are often the main risk affecting the development and operation of offshore wind farms.
Approximately 80% of insurance claims in the offshore wind industry are linked to cable failures. To reduce failure levels, DNV GL, ECN, WMC, BREM, VanderHoekPhotonics, Deltares and other partners are joining forces in a Joint Industry Project (JIP): Cables Lifetime Monitoring.
The aim of this study is to reduce the chance on power cable failures in offshore windfarms. One of the ideas which will be developed in this project is the continuous monitoring of the integrity of power cables during the whole lifetime by advanced use of optical fibre sensors.
“Continuous monitoring of the cable’s state of health enables early identification of possible failures,” explains Jan-Joost Schouten, an offshore expert at Deltares. “By preventing a significant number of cable failures caused by damage during manufacturing, installation and operation, we are convinced that our study will allow us to significantly reduce the levelized cost of electricity (LCoE) of offshore wind, in other words the average cost price of an electricity production unit over its lifetime. Reducing failure probabilities enhances the reliability of the energy network.”
Cable failures are one of the main risks affecting offshore wind operations because they can shut down an (important part of an) offshore wind farm for a duration of months, resulting in a financial as well as a societal impact. Despite the fact that power cables typically form only 5 to 10% of the total investment costs in an offshore windfarm, they account by far for most of the unavailability of the windfarms, and for claim costs of 100s of millions of Euros annually. In view of the development of the number of offshore wind farms, this amount will increase considerably in the future. Cable inspections and repairs are expensive maritime operations. Repairs on cables can easily take weeks or even months because of the weather or the limited available of equipment and vessels. That can severely impair revenue and also reduce the technical lifetime of offshore wind farms.