Tow-to-port strategies are feasible for floating wind farm component replacements but only in the short-term, a new study by World Forum Offshore Wind (WFO) has identified.
Based on the current state of technology, tow-to-port is considered the most accessible approach for early floating wind projects provided onshore facilities are available, WFO’s white paper, Challenges and Opportunities of Major Maintenance for Floating Offshore Wind, highlighted.
The white paper refers to findings from the ORE Catapult and Carbon Trust which show that tow-to-port is currently the lowest cost and most feasible option for major floating offshore wind repairs.
The white paper also stated that from a maritime operational perspective, a tow-to-port operation is complex involving many risks from the disconnection, moving in and out of field and heavy lift operations.
In addition to the associated safety, equipment and environmental risks (cost of operation), the interruption in electricity generation caused by disconnection of the FOWT is of “especially great concern to project developers and insurers”, which equals the cost of downtime.
The white paper said there is a need for innovations in moorings and electrical connectors that “allow for quick connection-disconnection and/or limits loss of production to the position(s) that failed in order to reduce downtime and loss of revenue”.
Lack of extensive FOWT-specific lessons learned on disconnection and reconnection procedures also poses contractual and certification issues related to the asset involved.
The white paper said an alternative for securing theoretical redundancy is to control spare parts: considering the predictive models for failure, having the correct parts and detailed plans for large correctives ready can help reduce downtime.
The deployment of standing assets from the harbour-side (overplanting) can also be considered.
The white paper also highlighted the tools applicable for tow-to-port will have to scale in tandem with the increasing turbine size.
“Currently, suitable cranage for larger assets remains scarce,” the white paper stated.