Wood Leads Study into Subsea Cables Seabed Stability

Wood has led a joint industry project (JIP) to improve knowledge and understanding of submarine cables behaviour on the marine environment and rocky seabed.

The CABILITY: Cable On-bottom Stability JIP, which gathered key industry players including EDF Energies Nouvelles, RTE, Naval Energies, VBMS, LDTravocean, Bardot Group, Silec Cable (General Cable) and DNV GL, has spent the last year developing a new set of industry guidelines.

Submarine cables are required to connect renewable energy sources such as offshore wind, wave and tidal power projects with the grid. However, it was acknowledged that the guidelines that are currently in place were originally derived from the oil & gas industry and are more suited towards assessing the stability of pipelines.

This anomaly can result in overly conservative designs with onerous recommendations and the need for expensive stabilisation systems which could, in turn, jeopardise the financial viability of new projects so the JIP has developed a new set of industry guidelines to address this.

This new methodology, which is based on numerical models calibrated with laboratory tests performed in the wave and current basin of the Oceanide test facility in the South of France, provides advice on assessing subsea cables on-bottom stability on rocky and non-smooth seabed.

This comprehensive parametric description of the physical mechanisms driving cables stability resulted in the implementation of an advanced methodology for on-bottom stability analysis with a significant gain in conservatism compared with previous standards.

Bob MacDonald, CEO of Wood’s Specialist Technical Solutions business, said: “The CABILITY: Cable On-bottom Stability JIP has really demonstrated the importance of industry collaboration. Our findings have acknowledged that there were over-conservatism issues but by working together we have developed a new set of guidelines which will ultimately deliver significant improvement of costs for both OPEX and CAPEX.”

Olivier de La Laurencie, St Nazaire offshore wind project director at EDF Energies Nouvelles, said: “EDF Energies Nouvelles is proud to have initiated this JIP which is aimed at developing our knowledge of the subsea cable on-bottom stability, as it contributes to improve the competitiveness of the offshore wind sector. The JIP CABILITY has provided a fair improvement on decreasing the level of the conservatism of the existing standards.”