A new £1m project to develop an innovative self-installing scour protection system could save the average wind farm approximately £8.6m over its lifetime.
Scour occurs when an underwater structure is subjected to currents and waves. Foundations used by offshore wind turbines can be susceptible to scour depending on site conditions, which can reduce the stability of this critical structure. Therefore, scour protection and prevention is vital.
The Innovate UK-backed, 20-month Self-Installing Scour Protection for Offshore Wind Farms (SISProtect) project is a collaboration between six industry partners all contributing their unique expertise.
The consortium is led by Great Yarmouth’s Seabed Scour Control Systems (SSCS) Ltd. The design of the prototype Frond Mat scour protection system, with an integrated deployment method, will be a joint effort between SSCS and SPT Offshore. SSCS will design the frond mats and SPT Offshore will design the deployment system.
The Self-Installing Scour Protection will then be fabricated and fitted to a suction bucket foundation designed and manufactured by SPT Offshore and installed by N-Sea at ScottishPower Renewables’ East Anglia ONE offshore windfarm. This field trial follows laboratory scour tests already carried out by ScottishPower Renewables with SSCS Ltd at HR Wallingford. A suction bucket without scour protection will also be installed, providing a reference for the level of scour that will develop naturally at the site and ensuring that the reduced scour measured at the protected suction bucket can be properly attributed to the Frond Mats; comparisons will also be made to the foundation rock armour used at East Anglia One.
The Offshore Renewable Energy (ORE) Catapult will analyse how this system compares in performance and cost with traditional scour protection systems, starting with the installation through to infield performance and decommissioning, and DHI Water Environments Ltd will monitor the offshore deployment and system performance over 12 months, after which time the system will be removed. ScottishPower Renewables will be responsible for site consenting, project management and providing access to the East Anglian ONE offshore windfarm site.
Adam Tucker, Subsea Division Manager at SCSS Ltd, said: “By pre-installing the scour protection system onshore and deploying at the same time as the foundation installation, this innovation will remove the need for environmentally damaging quarrying of rocks and diesel intensive installation vessels whilst providing a lower cost alternative to those currently available for the protection of offshore wind structures.”
ORE Catapult’s Financial Analyst Miriam Noonan added: “Installation costs typically account for over 75% of the overall cost associated with scour protection systems. By being able to deploy SSCS Frond Mats at the same time as the wind turbine foundation installation, the associated installation costs may be significantly reduced.”
[1] It is estimated that the protection system could reduce the Levelised Cost of Energy by 40p/MWh, based on 2016’s Cost Reduction Monitoring Framework. Analysis by ORE Catapult using the IEA reference windfarm at 496MW translates this into a cost saving of £8.6million per farm over its lifetime.