Sharing knowhow in offshore wind construction

We call it “The Transformer”

 

By Morten S. Pedersen, Westermost Rough Project Manager

At Westermost Rough, A2SEA has been working with Siemens Wind Power’s sophisticated tool for installing single blades at higher windspeeds and with greater safety. It’s impressive-looking, and it works just as impressively, too.

Until recently, the lifting approach and tools available to the offshore wind industry capped single-blade installation wind speeds at 8-10 m/s, leaving ample time to perform maintenance, practice safety drills or perhaps catch up with a game of cards in the saloon. With the latest lifting tool from Siemens, however, we can lift at speeds as high as 12 m/s, giving us better windows to do what we do best: install wind turbines at sea.

The tool itself resembles the claw of a giant metal robot. In fact, we joke that it looks like something straight out of the 2007 movie Transformers. And it’s every bit as effective as you might imagine a Transformer to be when it wants to get something done. It’s a fully automatic, specially developed mechanism that can easily lift the 75m single blades of a Siemens 6 MW wind turbine. The tool weighs about the same as you might expect a real Transformer would: 78 tons. And, at 14m long and 8m high, it has similar dimensions – if a metal movie monster were to lie down, that is.

In theory, the tool can be used in winds with sustained speeds of up to 14 m/s and gusts of up to 19 m/s. So far, however, the safe working limit for the tool is a more modest 12 m/s. In the near future, however, the various parties supporting the development of this powerful innovation (A2SEA and DONG Energy are working alongside Siemens) hope to achieve as much as 14 m/s and are working together to achieve this goal.

As you might expect, competing tools are under development. None use exactly the same approach as our Transformer friend and most require significantly increased lifting heights, which lowers operating wind speeds and increases the dimensions of related onboard infrastructure in a kind of Domino effect. But this is an industry where innovation truly thrives, so most likely, it’s just a question of time before we see more such tools contributing to bringing down the Levelised Cost of Energy. Let the Transformer Wars begin…

SAFE CHOICE

At 154m in diameter and weighing some 75 tons, a pre-assembled rotor for a 6 MW turbine would be almost impossible to transport and attach. So single-blade assembly is the only method that can be used for the latest generation of blades.

The tool fastens and tightens the cables fully automatically and is controlled safely from the ship’s deck. It can turn, tip, and swivel, lifting blades from any position on the ship. It can also tip or swivel blades for precise alignment with the hub.

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