Challenges and Opportunities of Major Maintenance for Floating Offshore Wind

At this point in time, offsite O&M for floating wind (tow-to-port, tow-to-shore) is considered most feasible for this generation of floating offshore wind projects because the technology and methodologies in this approach are known and more readily available. Nevertheless, developing an offsite plan will still require some technology innovations, e.g. in cranage for large turbines and quick connect-disconnect systems for mooring lines and dynamic cables, which at the moment are either scarce or at lower technology readiness levels [Figure 4].

Ultimately, the chosen maintenance approach for a given floating wind farm will be subject to various project-specific parameters including floater design, distance to port and associated weather window, harbour capacity and project cost-benefit analysis. While the lean towards offsite maintenance in the short- to medium- term is a conclusion shared by other studies that reviewed O&M concepts for floating wind, the outcomes of the discussions in the WFO Floating Offshore Wind O&M Subcommittee showed pertinent interest in onsite repair strategies.

These onsite approaches, namely floating-to-floating and self-hoisting equipment, are expected to perform major component exchanges in the longer term but require a serious evolution in the vessel and cranage industries. WFO participants have shared the floating crane vessels, self-hoisting equipment as well as analysis and modelling tools that their organisations are working on to fill this gap of necessary technology innovations.

The mobilisation of resources and investments to develop FOW O&M solutions requires capable actors to take the lead. Notably, OEMs, floating platform technology providers and developers were identified as the players that can and should spearhead the development of new floating wind O&M tools and solutions.

At the same time, incorporating O&M considerations early on in the timeline of floating wind projects can influence the bidding of technologies and methodologies that could eventually pay off in the OPEX phase. Commercial-scale floating wind projects will ask for a re-organisation of the ways project subpackages communicate with each other and share information.

The O&M phase is a gluing factor for all the different efforts involved in designing, building, insuring and commissioning a floating offshore wind project, and so studying its aspects at the pre-commercial stage of the industry we are in now will help achieve a sustainable large scale. In a next step, the O&M Subcommittee will further investigate the available tools and methods needed to carry out specific operations in tow-to-port, e.g. available cranes for MCR or disconnection of electrical cable and mooring lines. Meetings will continue to explore new areas, for instance FOWT accessibility with helicopter.