proactive approach to collaboration, with owners pre-planning for vessel sharing without engaging a full-time shared vessel. This form of flexible jack-up club offers the simplest starting point to improve readiness and facilitate rapid ad hoc shared vessel charters. This is achieved through proactive site assessment, contractual readiness, improved communication between windfarm owners and alignment of repair practices/ working methods and contracting. This approach avoids owners being required to commit significant budget to charter a vessel that they may not fully require and also enables rapid deployment. This improves the efficiency of jack-up vessel deployment and offers cost savings on mobilisation and usage. A flexible charter club introduces a lower risk, lower cost option to increase benefits to windfarm owners and takes its lead from a successful vessel collaboration seen recently on the east coast of the UK. The use of a club- based approach extends the concept to ensure heightened readiness with the potential to reduce vessel availability risk and associated production downtime. Until recently, the market for O&M jack-up vessels was limited to a small number of users and suppliers. Original equipment manufacturers (OEMs) were the predominant users of O&M jack-up vessels, with much use focused on meeting warranty commitments and guarantees. However, as the report notes, this landscape is rapidly changing as more offshore windfarms move beyond the initial warranty period and newer strategies emerge for sharing jack-up vessel risk within more recently agreed warranty contracts. Windfarm owners and operators are increasingly taking more responsibility for delivering arrangements for O&M jack-up vessels, which is leading to an increase in the number of users and a potentially


larger number of individual jack-up campaigns that are smaller in scope. Increased collaboration and the sharing of good practice to speed up jack-up vessel deployment now has the potential to improve the way jack-up vessels are used during the O&M phase. With increasing numbers of turbines now installed and clear geographical clusters emerging, this study identifies opportunities for industry-wide collaboration and other potential improvements in the use of jack-up vessels, which could speed up repair times, reduce maintenance costs and improve overall levels of electricity production. A wide range of maintenance activities is required at


offshore windfarms to ensure high availability and resulting commercial benefits. A key aspect of O&M requiring access to jack-up vessels is responding to defects and faults with main turbine components – blades, gearbox, generator and in-turbine transformer. In an offshore wind turbine, these are commonly located at the top of the tower either inside or connected to the nacelle (the only current exception being the turbine transformer, which can be located in the tower base on some models). Although turbines are often supplied on the basis that the main components have a design life of 20+ years, experience in smaller, mature onshore turbines has shown that, in reality, failures will occur. Some of the common defects off shore can be repaired in situ using teams that travel out to the turbine in a normal crew transfer vessel, using cranes located on the turbine. However, not all repairs can be made this way. Owing to the weight and size of some components, there are repairs that require a larger crane or need to be carried out externally to the turbine. There are also situations that require a replacement of the entire component to be made. Each of these components is heavy and typically cannot be lifted with


The Crown Estate believes that the LCOE could be driven down by more effective use of jack-ups


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