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The unexpected weight of hope

by Jerome a Paris Thu Mar 12th, 2009 at 11:49:58 AM EST


Princes Amalia (Q7) wind farm - Vestas V80 2MW turbines
June 2008, photo by author

When one sees pictures of offshore wind farms such as the one above, it is hard to conceive how incredibly big and heavy these things are. I have now visited the factories or construction site of all the major manufacturers of offshore wind turbines, and would like to give you a small glimpse of what it means to build these things... Follow me below the fold.

Part of the Wind Power series


First, some more pictures of the various turbines that are being used, or contemplated for, offshore wind today:


Thornton Bank (C-Power) wind farm - Repower 5M turbines
August 2008, photo by author


Hooksiel nearshore test site - BARD 5MW turbine
March 2009, photo by author


Bremerhaven test area - Multibrid 5MW turbine
(monopile foundation design in the background; tripod foundation design in the foreground)
March 2008, photo by author

The above are the 3 turbine models currently available in the 5MW range. The German market, where permits are given for wind farms with a given number of turbines, has focused on putting, naturally, the largest turbines in order to have the largest possible output for a given permit (and for a given transformer + development costs, as these items benefit from effects of scale). These 5MW turbines are still in their early days, with only a small number operational, but massive buildup plans. The other commercially available turbines for offshore are the Vestas V90 (3MW) and the Siemens 3.6MW machines - which have been selling (and are already installed) in larger numbers in markets like the UK and the Netherlands as of today.

As the last picture suggests, these machines are rather big. But let me show you how big, by taking a look at their foundations:


Hooksiel nearshore test site - BARD 5MW turbine
March 2009, photo by author


BARD 5MW turbine tripile foundation outside factory gates - Cuxhaven Steel Construction
March 2009, photo by author

The above is the specially designed tripile foundation for the Bard turbine, in the water, and outside the factory. That foundation has the advantage of being identical for all turbines, and can thus be mass manufactured: it rests on 3 steel piles which are adjusted to each site's conditions, and are smaller than a (bigger) monopile.


BARD 5MW turbine tripile foundation in construction - Cuxhaven Steel Construction
March 2009, photo by author

The above is one of the these foundations as it is being assembled inside the factory. As you can see, it gives a whole new meaning to "heavy industry."


C-Power turbine foundations in construction - Ostende
April 2008, photo by author

The C-Power project uses a "gravity-based" foundation design, ie a heavy concrete cylinder, later filled with sand, which simply rests on the sea floor. The above shows the foundations for the first 6 turbines as they were being built onshore, before being transported to site and filled there. They weigh about 3,500 tones empty, and double that full (for 25m water depths).


C-Power nacelle prior to erection - Ostende
August 2008, photo by author

The above is one of the Repower nacelles - that apparently small box on top of the tower is in fact a 300 ton (not counting the rotor) steel box bigger than a home. As can easily be understood, one of the most important issues for offshore manufacturing and construction is the availability of cranes to carry these things and ring them to their rightful position 80m above the sea level - and of the vessels that can handle that manoeuver in the middle of the sea.


Multibrid nacelle in factory - Bremerhaven
April 2008, photo by author

You've seen the foundation above; the nacelle assembly halls can be similarly impressive. Above is the Multibrid nacelle (prior to a redesign that will allow for a helicopter platform), which is actually the most compact of the three 5MW turbine designs.

So this is heavy industry - in fact, the main consideration to site the factories for the 5MW turbines and other elements (foundations, tower, blades is the logistics, as it is rather complicated to transport turbine parts, let alone turbines, and you need specially built ground floors and pontoon to withstand the weights that are carried around. So, quite logically, the factories are built near the sea, or near rivers. Cities with shipyards are ideal in that respect, with existing infrastructure, metal-bashing companies - and a rather strong desire to see the jobs lost in the previous decades reappear in this new industry.

Each of these manufacturers is creating jobs by the hundreds right now, and providing solid demand to a lot of subcontractors (gearbox manufacturers, electrical equipment, crane and lifting equipment manufacturers, transport companies) that also provide jobs. And the vast majority of these jobs will never be offshorised, because of the logistical constraints that apply on the industry.

Oh - and this will provide us with climate-friendly electricity that requires no imports of oil or gas and whose price will not move for the next 25 years.

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I should also note Greenpeace's just published report: Energy [R]evolution: A Sustainable USA Energy Outlook


In the Energy [R]evolution U.S. Scenario, Greenpeace and the European Renewable Energy Council (Europe's largest renewable energy trade association) posed a simple but daring series of questions. First, is it possible, using currently available technologies, to cut carbon dioxide (CO2) emissions worldwide to the levels needed to prevent the worst effects of global warming? Second, can we do it while also achieving strong economic growth? Third, since the dangers of nuclear waste and proliferation pose similar existential threats to humanity as global warming itself, can we also phase out all nuclear power by 2050? And, finally, can we do it here in the U.S.?

The answer, from some of the world's top energy experts at the German Aerospace Center (Germany's counterpart to National Aeronautics and Space Administration), is a resounding yes on all counts.

A Siegel has personal coverage of the press conference in Washington yesterday.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Thu Mar 12th, 2009 at 11:58:15 AM EST
I got the change to meet with CH and spend a couple hours with him. He seems to be enjoying the city!

In the long run, we're all dead. John Maynard Keynes
by Jerome a Paris (etg@eurotrib.com) on Thu Mar 12th, 2009 at 11:59:06 AM EST

From my visit to the Q7 wind farm (these are all Vestas V80 2MW turbines)


In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Thu Mar 12th, 2009 at 12:14:32 PM EST
by Lasthorseman on Thu Mar 12th, 2009 at 12:30:27 PM EST
I am led to believe there are considerable advantages from building onshore. Is there any reason why there is so much development offshore at the moment ?

keep to the Fen Causeway
by Helen (lareinagal at yahoo dot co dot uk) on Thu Mar 12th, 2009 at 12:54:44 PM EST
Hi there Helen. I don't have the same insight Jérôme has, but I've been studying Wind power for a long time and can give you some clues:

  • Windy spots onshore are running out - in the case of a small state like Portugal what I can tell you is that we are now moving into wildlife protection areas (usually mountain just tops). The only spots left are national wildlife parks - spaces were human intervention is reduced to the least as possible by law. This is the main reason why our government is trying to support the development of a Wave power industry. In the case of the US there are entire states where Wind is not an option by lack of proper high terrain.
  • Wind is a better resource offshore - windmills deployed offshore tend to work more time than onshore. Load factors (the percentage of time a turbine operates during a period, say an year) are usually 10% higher onshore than offshore - increasing from 25%-30% to 35%-40%. This extra wind provides for the extra logistics of deploying these incredible structures at sea. There's another important characteristic of Wind offshore: it tends to be more stable and to some extent easier to predict -this will have an important role in load balancing the electric grid.
  • The visual/environmental impact is lower at sea - onshore wind turbines have a true impact on the landscape, being this one of the major obstacle to its public acceptance. They also have a negative on bird life - especially in mountainous territory, where some studies showed them to take a real toll on preying birds. As far as I'm aware, offshore, the main potential impact on wildlife is on migratory birds. But a Danish study a few years ago showed that these birds can actually avoid the farms altogether, and even if crossing them these birds seem to be able to individually avoid the turbines and its blades, unlike their preying kin. Offshore wind farms can be designed in ways to actually have a positive impact on marine wildlife, although this is an issue I still have to study properly.

Right now my own reserves are on turbine lifetime, something for which data effectively doesn't exist yet. But given the heavy industry experience with oil and gas production and transport I expect whatever obstacles to appear on that chapter to be overcome with time.


Vencit omnia veritas.

by Luis de Sousa (luis[dot]a[dot]de[dot]sousa[at]gmail[dot]com) on Fri Mar 13th, 2009 at 05:05:20 AM EST
[ Parent ]
  1. some countries are running out of space onshore

  2. offshore, you can build wind farms like actual powerplants, on a GW-scale (with hoped for economies of scale and industrialisation, ie more potential to bring prices down and th possibility to replace large chunks of the power generation system

  3. wind is a better quality (less turbulence) and can be harvested at a higher altitude (where it is stronger)

  4. logistical issues prevent from building bigger turbines onshore as they cannot be transported around. Putting factories by the seaside for offshore use solves that.


In the long run, we're all dead. John Maynard Keynes
by Jerome a Paris (etg@eurotrib.com) on Fri Mar 13th, 2009 at 04:18:39 PM EST
[ Parent ]
nice insight into the crazy logistics of building these things

what size does a windfarm have to be these days to be commercially viable onshore or offshore ?

by darragh on Thu Mar 12th, 2009 at 01:24:43 PM EST
Related to that question, are their optimal sizes for off shore and onshore turbine designs taking into account the costs and engineering/logistical challenges, or are we going to see an ongoing trend towards giantism?

I would have thought onshore designs might be more economic if produced from mass produced components capable of being transported by reasonably standard road vehicles - e.g. Max dimensions c. 15X3X5M and max weight c. 50 Tonnes per component?  Is there a point at which bigger becomes more expensive per unit out put?

What are the estimated lifespans of these major components - given sea water corrosion, storm damage, wear and tear etc. - do they degrade beyond maintenance at some point?  If they do, we will have a significant decommissioning cost and a significant carbon footprint over their lifespan.  Do we know what this is compared to other power sources?

notes from no w here

by Frank Schnittger (mail Frankschnittger at hot male dotty communists) on Thu Mar 12th, 2009 at 01:59:48 PM EST
[ Parent ]
Max dimensions c. 15X3X5M and max weight c. 50 Tonnes per component

Won't go. Blades are much longer, they need special vehicles. But those exist. However, transport is only a very small part of the overall cost for onshore turbines. For offshore ones, I suspect the size of the foundation necessary and the construction cranes is a more relevant limitation than transport.

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

by DoDo on Fri Mar 13th, 2009 at 07:26:18 AM EST
[ Parent ]
The most significant part of the carbon footprint is and remains the steelmaking. Decommissioning of the turbine itself should be easier than construction, and it was practised when the generators of all turbines in the Horns Rev offshore wind farm in Denmark had to be replaced in 2003-4, a year after commissioning (they were corroded due to faulty saltwater insulation design) - maybe Jérôme knows the costs involved and what became of the parts of the removed generators.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Mar 13th, 2009 at 07:34:46 AM EST
[ Parent ]
That depends both on the wind yield and the financial conditions in the country you want to build one. One single onshore turbine can be commercially viable.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Mar 13th, 2009 at 07:22:19 AM EST
[ Parent ]
depends on wind conditions onshore, and distance to grid. There is no size that seems more advantageous than any other.

Offshore, you have large fixed costs in the form of the cable to the grid, and the transformer station. So, in principle, the larger the better - at least 200MW, and more if, like in Germany you need to go quite far from the shore.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Fri Mar 13th, 2009 at 04:20:37 PM EST
[ Parent ]
Hi Jérôme. I'm getting curious on one thing: is there anyone already developing the 10 MW turbines Eddie O'Conner talks about? Or is it still a dream? A good dream anyway...

Vencit omnia veritas.
by Luis de Sousa (luis[dot]a[dot]de[dot]sousa[at]gmail[dot]com) on Fri Mar 13th, 2009 at 05:08:35 AM EST
The currently biggest are Enercon's E-112 (second batch) and E-126 at 6 MW, but the E-126 are probably suided for an up-rate (for comparison: the first batch E-112 were rated for 4.5 MW).

American companies are aiming for bigger: Clipper Windpower for 7.5 MW, while AMSC Windtec aims for 10 MW; but I suspect these aren't to be taken that seriously.

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

by DoDo on Fri Mar 13th, 2009 at 07:08:22 AM EST
[ Parent ]
Some pictures of the two E-126 currently in construction in Hamburg (these have nacelles even bigger due to their direct generators) from Hansebubeforum:



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

by DoDo on Fri Mar 13th, 2009 at 07:20:08 AM EST
[ Parent ]
The 5MW turbines are barely out of the prototype stage yet. The big manufacturers are keeping ilent about their future models, but it's likely that they are working on bigger ones.

In the long run, we're all dead. John Maynard Keynes
by Jerome a Paris (etg@eurotrib.com) on Fri Mar 13th, 2009 at 04:21:40 PM EST
[ Parent ]


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