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Offshore wind photoblogging - installation vessel edition

by Jerome a Paris Thu Sep 6th, 2012 at 05:27:46 AM EST

On Monday, I was invited to the christening in Bremerhaven of the biggest special purpose vessel to be built for the offshore wind industry to date, the Innovation:

The vessel is owned by a joint venture of Hochtief, the German construction group, and DEME, the Belgian marine works group, and will be put to work first by Areva on Globaltech 1, one of the big wind farms in construction in Germany now (and one that was project financed) and later on Northwind, a Belgian offshore wind farm (also project financed, in this case with the involvement of my company).

The godmother of the vessel is Mrs van Rompuy, as befits a truly pan-European industrial development (the vessel was assembled in Poland, the owners are Belgian and German, with respective large French and Spanish shareholders, the first client is French and the base of operations is in Germany).

The ceremony took place in Bremerhaven, a city being transformed by the offshore wind industry, and with the perfect backdrop of ongoing construction work for several offshore wind farms. See some more pictures below - including from the boat itself, as the guests were allowed to visit large bits of the vessel.

You can see the ship and its huge crane standing alongside the tripod foundations that have been manufactured for the offshore wind turbines and are now waiting to be shipped out. The vessel will be able to carry 3 of these tripods, plus the 3 smaller piles for each tripod used to "nail" these into the subsea floor (you can see some of these piles already on board the vessel in the pictures below). In this case, there will be 'post-piling', ie the tripods are lowered on the sea floor first and then the piles are driven through into the seabed; it is also possible to do 'pre-piling' - the small piles re driven into the ground first, and then the foundation is lowered onto them and positioned on them like a big lego game.

One of the features of the vessel is its large crane, allowing to carry the loads required at sea (the owners say there will be able to install turbines and associated equipment of up to 10 MW). An interesting feature of this vessel is that the crane is built around one of the legs of the ship (more on these in a second), allowing it to have a lot more freedom of movement, in particular its overall angle of rotation.

The legs are an essential part of the vessel, as they allow it to "jack up", ie to stand on these legs as they are lowered down on the seafloor, and be perfectly stable for construction work even if the sea is not calm. An important parameter of these legs is how big they are, which drives the sea depth at which the vessel can work - in this case the vessel can work up to depths of 50m, meaning that it will be able to install turbines and foundations in most of the North Sea. The vessel is also self-propelled, meaning that it can go back and froth from construction site to harbor on its own, without need for tug boats (a number of existing jack up vessels are simple barges which need to be dragged around).

We were allowed to walk on the helipad at the top of the structure, and to enjoy the view - as can be seen above, Bremerhaven is a city fully dedicated to the wind industry, with multiple (onshore) wind turbines installed nearby - in the case above, it's one of the testing sites for new turbines, where some of the first 5MW turbines were installed to be tested onshore, and where the jacket foundation concept was test in full scale.

A nearby barge carried some jacket foundations for the NordSeeOst project being built by RWE, alongside the tripods for the Globaltech and Borkum West projects

With lodging for 180, it's a hotel ship for the installation crew as well, wow.

"Life shrinks or expands in proportion to one's courage." - Ana´s Nin
by Crazy Horse on Wed Sep 5th, 2012 at 01:59:31 PM EST
It's good to see that people are making long term commitments towards the growth of the industry.

It's such a shame that the UK govt is almost ashamed of the amount of money being spent, because there is so much of the manufacture and infrastructure which could be based here if only they'd get behind the industry

keep to the Fen Causeway

by Helen (lareinagal at yahoo dot co dot uk) on Thu Sep 6th, 2012 at 06:21:48 AM EST
Fantastic stuff - I love your offshore wind photoblogging. It's just thrilling. (Am I normal?)
by LondonAnalytics (Andrew Smith) on Thu Sep 6th, 2012 at 11:12:55 AM EST
by asdf on Thu Sep 6th, 2012 at 12:11:12 PM EST
Well, other than the title, the article is actually not so bad (and it talks about the project we helped finance last year).

Wind power
by Jerome a Paris (etg@eurotrib.com) on Thu Sep 6th, 2012 at 12:54:55 PM EST
[ Parent ]

Six corporations will start construction in the coming days. German electric utilities RWE and E.on are also building large wind farms near the WindMW site. Trianal GmbH, an alliance of municipal utilities, is building a wind farm 45 kilometers north of Borkum, while the Swedish power company Vattenfall will be at work 70 kilometers from the North Sea resort island of Sylt.

Windreich AG has chartered the world's most powerful crane ship, the Innovation, whose crane can lift 1,500 metric tons. In the next few days, the ship will haul steel tripods out to sea, which will serve as the foundations for the "Global Tech I" wind farm more than 90 kilometers offshore.

The entire North Sea coast is gearing up to implement the various monumental projects. Wharfs with heavy-duty hoists and new offshore terminals are being built all along the coast, stretching from the port of Bremerhaven to that of Husum, just south of the Danish border. Behind them are plants where massive lattice frames and pipes are being welded together.

The law on offshore wind was announced in December 2007, and here we are, less than 5 years later, with €10 billion committed (and to a good extent spent) on a massive effort by all the players in the sector the build the sector from scratch, in one of the most hostile environments on earth.

It doesn't look like it's going so badly. Sure, some projects are 6-12 months late. Do we say that civil works are doomed when a big bridge or highway is late by that much?

Wind power

by Jerome a Paris (etg@eurotrib.com) on Thu Sep 6th, 2012 at 01:34:17 PM EST
[ Parent ]
Impressively massive.
by In Wales (inwales aaat eurotrib.com) on Thu Sep 6th, 2012 at 04:56:51 PM EST
Agreed. I didn't think anyone outside China did things on that scale. Good news.

sapere aude
by Number 6 on Thu Sep 13th, 2012 at 09:38:44 AM EST
[ Parent ]
by Jerome a Paris (etg@eurotrib.com) on Fri Sep 7th, 2012 at 09:13:14 AM EST
And added to the Wind Power series.

Wind power
by Jerome a Paris (etg@eurotrib.com) on Fri Sep 7th, 2012 at 09:16:06 AM EST
[ Parent ]
"[]... able to install turbines and associated equipment of up to 10 MW"

Forgive my ignorance: is that a lot?

(I see numbers such as 135m tall for 7MW, so I'm guessing they'll be large.)

sapere aude

by Number 6 on Thu Sep 13th, 2012 at 09:41:44 AM EST
In relation to this, Jerome you write on the Kos:

Urban wind is not a good idea, as the wind resource is not good (turbulent, irregular, blocked by buildings, etc) and you can't build the turbines high enough (where the wind is better).

Does this still hold for these gentle giants? Does extending the tower (as they do in forests) help any?

by mustakissa on Fri Sep 14th, 2012 at 02:47:04 AM EST
[ Parent ]
Welcome to ET, mustakissa.
by afew (afew(a in a circle)eurotrib_dot_com) on Fri Sep 14th, 2012 at 02:50:44 AM EST
[ Parent ]
Yes. Read this and this.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Sep 14th, 2012 at 03:07:40 PM EST
[ Parent ]
Quoting from the second:

Speed calculation - Windpower Guided Tour

As an example, have a look at the spreadsheet above. We have already entered 10 m/s at 100 m height in roughness class 2. You will notice that the wind speed declines as you approach ground level. You will also notice that it declines more rapidly in rough terrain.

Remember that the energy content of the wind varies with the third power of the wind speed. If you look at the column with roughness class 2, you will see that wind speeds declines 10 per cent going from 100 metres to 50 metres. But the power of the wind declines to 0.9 3 = 0.73, i.e. by 27 per cent. (From 613 to 447 W/m 2 ).

Roughness class 2, which corresponds to wind theoretically coming to a standstill 0.1 m above ground, is "Agricultural land with some houses and 8 metre tall sheltering hedgerows with a distance of approx. 500 metres".

For urban wind, roughness class 3 or above and hub heights around 10-20 m are relevant. For roughness class 3, if wind speed 100 m above ground is 10 m/s, the calculator gives 7.09 m/s resp. 6.83 m/s at heights of 20 and 10 m. In power, that means a 64.4% resp. 68.1% reduction...

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Fri Sep 14th, 2012 at 03:19:10 PM EST
[ Parent ]
Actually I was more thinking of hub heights of 150 m.

And shouldn't you rather be looking at the effect of roughness class at that given height? I.e., 8.44 m/s vs. 13.1 m/s, for a power loss of 73%. Too much anyway.

by mustakissa on Sat Sep 15th, 2012 at 04:25:34 AM EST
[ Parent ]
I guess it would be possible to put large wind turbines high enough in urban settings that the wind resource is good - but the issue there is typically that it won't be accepted by the population.

The rule in rural areas is that turbines should be 500-800m away from the nearest habitation (the number changes in each country). In urban areas, you could argue that noise is largely irrelevant, as is the visual impact, but it hasn't happened - not in densely populated areas. Bremen does have wind turbines around the city, a number of port cities have put turbines along quays, and you do see turbines along highways in various cities in the Netherlands, so it has been done, but it remains relatively limited.

Wind power

by Jerome a Paris (etg@eurotrib.com) on Sat Sep 15th, 2012 at 05:21:31 AM EST
[ Parent ]
I suspect weight is more an issue than hub height. Power is roughly the linear function of swept area, so the blades of a 10 MW unit need to be around 20% longer than that of a 7 MW unit. (Hub height increases even less, because it is blade length plus the safety distance from the sea surface which AFAIK doesn't change with power.) However the mass of the turbine minus tower is probably close to volume-proportional when scaled up, that is, increases with the third power of the blade length. In our example, that means an increase of about 70%!

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Sep 14th, 2012 at 02:42:44 PM EST
[ Parent ]
In these trying times of crisis and universal brouhaha,
wind power is one of the few things that give me hope for the future.

sapere aude
by Number 6 on Thu Sep 13th, 2012 at 09:43:35 AM EST

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