A number of years ago, it was normal practice for offshore contractors to win major offshore wind turbine installation projects using non-propelled jack-up barges supported by tugboats and anchors for positioning. This was the established way – it was safe, reliable and efficient.
Then, in around 2011, the introduction of second-generation jack-up vessels brought Dynamic Positioning Systems (DP systems) into play. This became the new ‘state of the art’. In the typical progression of ‘order winners’ becoming ‘qualifiers’, today, vessel owners are not even invited to tender if their installation vessels are not DP2-capable.
If you consider offshore lifting operations of large components such as turbine blades, there is a strong parallel to that of vessel positioning before DP2 became the industry standard. During the lift, manual winches, people with ropes and, in some cases, simple constant-tension systems try to keep the blade under control during the lift. You could compare it to the tugboat-and-anchor method of positioning your jack-up barge. Continue reading
The lifting process on jack-up vessels is a key process in any offshore wind turbine installation or maintenance project. Control systems such as tagline systems are a necessary part of the lifting setup. Their purpose is to help manoeuver loads – such as wind turbine components – to the desired point accurately and safely.
The most obvious source of movement of a hoisted load is due to inertia and wind. Yet the solutions for controlling these motions are subject to other practical constraints that often make it difficult to achieve sufficient control during the lifting process. Continue reading
As offshore wind turbine sizes grow rapidly, the technology needed to install and commission turbines is not following suit. This is a significant barrier to progress in the offshore wind industry and is continuing to make it difficult to reduce the levelised cost of energy.
Today’s wind turbines and the associated installation technology, such as taglines, have been created from the same baseline. But it is all essential just an incremental evolution of technologies that have been moved from onshore to offshore. There have been no significant design revolutions.
At the same time, we are using the same technology developed for smaller turbines and assuming it will deal with 8MW turbines – and bigger. We are increasingly demanding more from the equipment, but in reality the technology has its limits. Continue reading