The cables technical working group is one of five technical working groups of the Offshore Wind Accelerator (OWA), consisting of experts from each of the OWA’s partner organisations and the Carbon Trust. It aims to identify technology and process improvements to reduce subsea cable failure rates and associated downtime, optimise cable performance in operation, and reduce installation costs.
Cable-related incidents account for 80% of insurance claims for offshore wind farms, with 60% directly relating to cable damage during construction. The cost of cable supply and installation for wind farms typically account for 8-12% of overall CAPEX costs. Improving the cable installation and operation is fundamental driver to cost reduction.
The group runs collaborative projects engaging with universities, cable manufacturers, innovators, installers, insurers and the wider supply chain, to address knowledge gaps and suggest innovative solutions to improve cable performance and reduce failure rates.
“Wood are really pleased to have supported the Offshore Wind Accelerator on several projects in recent years. The programme is constantly at the forefront of innovation to drive down the costs of offshore wind.”
Brian O’Keeffe, Wood
Projects
Below are examples of key pieces of work from the cables technical working group. Recent projects include:
- investigations of cable monitoring systems
- exploring the potential benefits and specifications of a ‘universal joint’
- a study to better design cables for semi-dynamic environments and reduce risk of associated failures
- investigating the impact of soil thermal properties on offshore wind inter-array and export cable design.
Cable Protection Systems (CPS) best practice guideline
The Cable Protection System (CPS) IV project aimed to address the challenges and gaps in existing standards, particularly at the interface between cables and windfarm foundations. By consolidating industry knowledge and establishing consistent requirements, the project sought to enhance the reliability and effectiveness of CPS systems. The standardised framework offered by the CPS IV project is intended to be a valuable resource for all stakeholders involved in the development and operation of offshore wind farms.
Fibre Optic Cable Protection Assessment reports and design recommendations
The industry identified cable failure as a high-profile issue and the OWA’s Cables Working Group commissioned the Fibre Optic Cable Protection Assessment project to validate modelling undertaken by Ørsted and Nexans to suggest design recommendations to mitigate risk. The recommendations are likely to increase the cost of the export cable between 0-0.5% depending on the design that it replaces, and will not affect the installation cost. Therefore, overall savings remain significant based on the costs incurred through cable failure.
Guidance for geophysical surveying for unexploded ordnance and boulders
In 2020 the OWA developed and published guidance to support offshore wind developers and surveyors with subsea cable installation. Data from geophysical surveys undertaken in the planning stages of offshore wind farms form a key part of the knowledge base for risk evaluation and management, and can cost millions of pounds. This first of its kind guidance sets our best practice for the creation and utilisation of data, the structure of surveys and documentation of results.
Cable Burial Risk Assessment (CBRA) guidance and application guide
At the time of development, the absence of a suitable method of assessing risk management in cable burial had led to a proliferation of approaches from developers. 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.
Contact
For any questions relating to the cables working group please contact owa@carbontrust.com.
