OWA Advises on Cable Burial Risk Management

The Carbon Trust’s Offshore Wind Accelerator (OWA) has published a new guidance on risk management of cable burial for the first time.

The Cable Burial Risk Assessment (CBRA) Guidance offers a standardised, repeatable and qualitative method to improve risk management of subsea cables for offshore wind farms, improve conservative estimates of residual risk, and ultimately reduce the installation and insurance costs for subsea cables.

Cables are the root cause of the most frequent and largest insurance claims against offshore wind developments. According to industry figures shared by GCube, specialist offshore underwriter, over 80 per cent of construction projects have resulted in a cable related incident. Over half of these claims are solely down to incorrect installation and load out of cables. Between 2007 and 2014, the cumulative costs to insurers was £75 million with over 60 incidents alone resulting in pay outs of between £0.5 million and £13.5 million per claim.

The CBRA Guidance provides a risk based assessment and enables the burial Depth of Lowering specification to be optimised. In addition, it provides a means to assess the residual risk to the cable after burial operations are complete to a specified depth.

Dimitris Kostopoulos, Electrical Systems and Cable Installation Project Manager, OWA, the Carbon Trust, commented:“The Guidance details a pioneering method to evaluate the real external threat to cables based on actual site conditions available for all stakeholders. For the first time CBRA enable the cable protection level to be assessed once the installation operation is performed through the evaluation of the residual risk, as well as over time, by periodically updating the site survey data.”

Claus Fridtjof Christensen Lead Principal Specialist, DONG Energy Wind Power said: “As the guidance refers to a lot of background information and has been developed together with – and reviewed by the industry, the suggested values and related uncertainties are aligned with the industry. The CBRA Guidance therefore gives a good common methodology for the industry and will also ensure that risk assessments can be compared.”

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