Lifting operations

Lifting of large components is an essential part of installation and operations & maintenance of offshore wind turbines. Blades, nacelles, towers and gear boxes need to be lifted and positioned carefully, often in windy conditions far out at sea. Efficient lifting depends on the ability to operate advanced crane equipment and dedicated jack-up vessels. Weather downtime caused by high winds and heavy seas leads to project delays, increasing installation and maintenance costs. Project owners, vessel owners, crane manufacturers, and wind turbine manufacturers have a joint responsibility to improve the efficiency and robustness of lifting operations.

The articles below contain opinions, recommendations, learnings and experiences from crane and lifting professionals in the offshore wind industry. They explore issues related to making lifting operations more efficient, robust and reliable.

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Crane rails: Why they improve offshore lifting capabilities

As demands on offshore wind installation processes increase, crane technology is being pushed to its limits. Not only do offshore cranes need to lift heavier and larger wind turbine components, but they also need to operate in more gruelling weather conditions.

Increasingly, vessel owners and contractors are looking to meet these demands by boosting crane capabilities with technologies such as taglines and various forms of intelligent lifting systems. But there are important implications of these additional demands that impact crane design and performance.

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Intelligent guidance for offshore lifting: The next DP2?

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 →

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How to overcome technical constraints of the offshore wind lifting process

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 →

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Reducing weather downtime in offshore wind turbine installation

Recent advancements in technology can bring about a long-awaited positive development in the offshore wind industry: reducing weather risk associated with offshore wind turbine installation.

Difficult weather conditions often lead to significant project delays caused by downtime that extends project time and increases costs.

Of course, weather downtime is an unavoidable part of any installation process and must be figured into project costs alongside all of the different activities required of the jack-up, including mobilisation and demobilisation, loading of the wind turbine elements, transit between the port and the wind farm, positioning and jacking, and installation of the turbine. Continue reading →

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Lifting operations

How to calculate wind effects in large blade lifts

The installation of offshore wind turbine components has traditionally been limited by metocean factors such as spudcan impact during jacking, crane dynamic amplification factors and, of course, wind effects.

Now, a new range of modern, larger jack-up vessels has entered the market, bringing higher jacking windows and heavier cranes. At the same time, foundation sizes are increasing, with the market moving to larger, higher capacity turbines.

Wind during installation can have a big impact on blade installation activities. And this impact will only increase as blades become larger. Continue reading →

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Risk mitigation through robust offshore wind solutions

As the offshore wind industry continues gaining in maturity, with more investment commitments across Europe, risk mitigation is becoming an increasingly important area for developers and investors.

Insurance providers have an important role to play, providing not only financial solutions for risk mitigation, but also helping wind turbine installation projects to get on track again in the event of a major incident.

But avoiding such incidents is in the interests of all. Indeed, the offshore wind industry needs to work towards more robust solutions that guarantee completion of offshore wind turbine assembly and repair.

If a claim is made, however, and the insurance provider steps in to complete the installation, it is vital the installation is completed quickly. Continue reading →

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Reducing weather sensitivity of turbine component lifting significantly reduces LCOE

BVG Associates has recently analysed the effects of increasing the wind speed limit for turbine component lifts. The results of this analysis are described in detail in a new report, “Impact of the Boom Lock tool on offshore wind cost of energy”.

The report, available exclusively on this site, quantifies the impact on levelised cost of energy (LCOE) of reduced vessel use and earlier power generation, based on the use of the “Boom Lock” tool.

The report concludes that reducing weather sensitivity of turbine component lifting significantly reduces LCOE. Continue reading →

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Lifting operations

Turning weather risks into a window of opportunity

To improve profitability, offshore wind farms are moving further offshore and significantly growing in size. The latest example is the 1200 MW Hornsea project, located 120 kilometres off the UK coast with more than 170 turbines.

With further offshore locations, more severe weather conditions follow, particularly with respect to wave and wind conditions. Far-shore offshore wind sites in the German North Sea have wind average wind speeds of 10+ meters per second.

From an energy generation perspective, these conditions are excellent. The flip side of the coin is however that the conditions can present a significant challenge during installation and weather remains a critical factor for the project’s success. Continue reading →

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How can contractors contribute to a sustainable offshore wind industry?

Offshore wind now accounts for about 7% of European renewable energy generation. Most of this new capacity has been built since 2015. Although the rate of growth has been slower than many expected or hoped, it is still a significant shift in the way Europe generates electricity. The change has been biggest in the UK, where offshore wind now generates about 5% of all its UK electricity demand.

But it hasn’t been cheap. In 2012, new offshore wind farms at final investment decision (FID) had a levelised cost of energy of about €150/MWh. At the time, the ambition was to get to about €110 for projects reaching FID in 2020. Led by the rapid introduction of next generation of offshore wind turbines, recent analysis by BVGA suggests that the 2020 target is well within reach. Continue reading →

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What’s next in offshore wind installation technology?

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 →