6. Concluding remarks
In this study, a comprehensive novel methodology of O&M
planning for offshore wind farms is introduced towards optimum
O&M cost, minimum revenue loss, and maximum power production.
Climate parameters, failure characteristics of different failure
modes, and different transportation systems (helicopter, crew
transfer vessel, offshore access vessel and jack-up vessel) are
simulated within the operational phase of an offshore wind farm.
The results are demonstrated to support the decision making
related to the O&M and logistics strategy. The consequences of
different decisions can be assessed and favourable solutions,
which bring the highest financial and operational benefits, can
be selected.
In this context, it is identified that the cost of jack-up vessel
related operations is significantly higher than any other transportation
system in the O&M fleet. Therefore, the jack-up vessel
charter period has to be investigated carefully, before chartering
the jack-up vessel. From preventive maintenance point of view,
second half of the year can be too late to start these operations.
Due to higher accessibility than conventional CTVs, helicopter is
an important aspect in the O&M fleet; however, the helicopter
operations can be performed in a more cost-effective way when
the offshore wind sector becomes more mature. It is clear that
human interventions at offshore environment need to be reduced
and the possibility for remote condition monitoring need to be
fully exploited. As the number of turbines in offshore wind
projects increases, and the wind farms are located further away
from shore, there is a need to develop specialised new O&M
vessels and transfer systems that will provide access to turbines
throughout the year in rough sea conditions. New approaches
may involve moving from port-based operations to ship-based
strategies.