DNV GL, ECN, WMC, BREM, VanderHoekPhotonics, Deltares and other partners have started a Joint Industry Project (JIP) named “Cables Lifetime Monitoring” to reduce failure levels in offshore wind farm cables.
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, Deltares explained.
“The aim of this study is to reduce the chance on power cable failures in offshore wind farms. 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,” said Jan-Joost Schouten, an offshore expert at Deltares.
“Continuous monitoring of the cable’s state of health enables early identification of possible failures. 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,” he added.
Despite the fact that power cables typically form only 5 to 10% of the total investment costs in an offshore wind farm, they account by far for most of the unavailability of the wind farms, and for claim costs of 100s of millions of Euros annually.
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.
An earlier analysis conducted by DNV GL already showed that cable failure is partly attributable to manufacturing, design and installation errors. In addition, it is known that morphodynamic processes such as sand waves can effectively expose submarine cables, which significantly increases the risk on third party damage.
The knowledge regarding the major causes of power cable failures will be further enhanced by analysing the failure data of a.o. the JIP participants. This will be focused on extracting lessons learned and points for improvement for the industry.
The project runs from mid-2018 to mid-2020. The partners in this project expect to be able to reduce the LCoE, insurance costs and the CO2 footprint of the offshore industry by increasing the reliability of offshore wind energy.