Scots-led wind-ustry working group recommends removing ‘gold plated’ rules for submarine power cables to cut costs for offshore turbine farms

A joint wind-ustry supply chain project has spent the last year developing a new set of guidelines to improve knowledge and understanding of submarine cables behaviour on the marine environment and rocky seabed.

In effect the ‘Cable Bottom Capability’ project – led by Aberdeen-based Wood Group – has recommended that ‘gold plated’ rules on submarine power cables for N. Sea oil installations be removed for offshore renewable energy generators.

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 and 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.

The project group also included EDF, RTE, Naval Energies, VBMS, LDTravocean, Bardot Group, Silec Cable (General Cable) and DNV GL

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 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, head 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.”

28 Feb 2018