Offshore wind turbine design - Wind Power Generation and Wind Turbine Design - page 375

and development for offshore wind industry need to be based on the oil and gas
experience that can be leveraged. This requires collaboration between the wind
turbine manufacturers, who command the necessary understanding of loads, mass
production issues, and the overall system design and economics trade-off issues,
and the world-class institutions with specifi c expertise in developing oil platforms
foundation technologies.

4.5 Corrosion, installation and O&M challenges

Corrosion, installation and operation and maintenance challenges are also essen-
tial to the success of the offshore wind power plant.
Most offshore wind turbines components have been coated, cathode protected
and/or sealed per the typical naval military standards (MIL) to protect them from
the excessive corrosive environment offshore. However, severe corrosion problem
has still been observed on a major EU OEM's electrical system and resulted in
very expensive large-scale replacement of the electrical components in the fi eld.
Hence identifying the difference in the corrosion root cause between the naval
vessel and the offshore wind turbine is something that needs further exploration.
On top of the corrosion issue, the installation of the offshore wind turbines,
foundations and electrical infrastructures has been a major cost and schedule
challenge due to

• The uncertainty in the weather, wave, current and soil conditions.

• The involvement of specialized large installation service equipments such as

large hammers for pile driving and jack-up vessels for crane and general
handling of the turbine.

To make large offshore wind project feasible, new installation concepts, tech-
nologies and equipments are needed to reduce the overall installation cost and
extend the installation window period.
Furthermore, the operation and maintenance of the offshore wind plant requires
special access capability to and survivability on the wind turbine in a variety of
wind and wave combined conditions. Boat access is slow and the landing to the
turbine can be dangerous even in the normal wave conditions. Helicopter-based
access has been developed and preferred for its fl exibility and speed. It requires special
landing pad design for the turbine though. Many efforts have been invested in the
condition-based monitoring (CBM) systems to minimize the need for human access.

4.6 Environmental footprint

There is a need to have independent and scientifi cally based studies on the true
environmental footprint of offshore wind power plants. Expertises exist with
regards to assessing environmental footprint, particularly on naval mammals and
fi sh schools, in the north-eastern U.S. with institutions such as the joint marine
biology program between MIT and Woods Hole Oceanographic Institution. These