Carbon Trust’s Offshore Wind Accelerator programme is inviting tenders for windfarm engineering R&D services.
A significant number of UK offshore wind farms have experienced difficulties associated with the installation and burial of intra-array cables. In 2011, the OWA commissioned a study to develop recommendations for optimised cable installation methodologies showing that optimising the way of doing cable route surveys and burial depth analysis has the potential to reduce the overall lifecycle cost of a wind farm.
There are many risks associated with subsea cable installation and maintenance. Although cables typically represent only ~8% of the total offshore wind farm investment, they are responsible for ~90% of the total number of insurance claims. For these reasons, the aim of this study is to minimise risks and reduce the cost of cable installation and maintenance for Round 3 wind farms.
This will be achieved by matters including:
1. reviewing the cable route survey and burial depth methodology: Baseline current burial techniques and investigate burial techniques being used in other industries; Establishing the minimum criteria for geophysical/geotechnical data and data interpretation in terms of quality, resolution, etc.;
2. benchmarking the cable burial equipment: Understand what the limitations are of each burial tool, which is the best burial tool to use for different soil conditions and associated installation strategies;
3. developing a cable burial protection index specific to Round 3 sites: Taking into account the severity of the losses associated with power cables (e.g. loss of revenue, repair costs, etc.) as opposed to those also associated with oil and gas, such as environment pollution issues: Provide increased clarity of the risks to cables within a wind farm; Understand the limitations of the current Burial Protection Index originally designed for oil and gas; Allow for a better understanding of actual burial depths required with respect to the associated risks of an area; Provide assurance to insurance companies that there is a higher level of risk management and mitigation amongst developers, with an aim to reduce insurance premiums; Offer cable installers a more in-depth view of the wind farm and cable risks; Provide a framework for developers to decide which cable burial technique is most appropriate for their site;
4. understanding the cost benefits of the combined optimisations: Allow for more appropriate costing upfront including better advanced planning and smoother installation, as there will be a better understanding of the actual risks
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Offshore WIND staff, August 5, 2013; Image: abb