Law & Disorder / Civilization & Discontents

Governments fund research into floating wind turbines

Huge generators would operate in waters over a thousand feet deep.

Norway's 2.3-MW Hywind floating turbine may form the blueprint of the larger turbines to come.

The US and UK last week announced plans to develop enormous floating offshore wind turbines that can be deployed in much deeper waters and further out to sea.

By being freed of the towers that would usually tether offshore wind turbines to the seabed, floating turbines are not restricted to the usual 60-meter (200-foot) depth limit, and instead can be located in waters several hundred meters deep. Not only does this increase the areas of sea and ocean that can be harvested for wind, it grants access to faster and more reliable winds. And because wind turbines can be located further from the coast, they can be positioned beyond the sight of inland communities that may be less than impressed by the insertion of a wind farm into their scenic coastal view.

Last week Energy Ministers from the world's 23 largest economies met in London at the Clean Energy Ministerial co-chaired by US and UK Energy Secretaries Steven Chu and Edward Davey. In a statement issued ahead of the event, Davey announced that both the US and UK would be "making funding available," and described the two countries as being "determined to work together to capitalise on this shared intent."

Though couched in rather vague language, the statement does go into more detail as to the funding available. The UK's Energy Technologies Institute (ETI) is currently commissioning a £25 million ($41 million) floating demonstrator project. Selected participants will be invited to submit concepts of a floating wind turbine between 5 and 7 megawatts (MW) capacity. The winner will be asked to produce a working prototype to be installed by 2016. In the meantime, the ETI is narrowing down sites that could host the demonstrator. The additional waters opened up by floating wind technology allow access to hundreds of of gigawatts of additional wind resources. The UK's offshore wind potential has been calculated at 2200GW, which is thought to be about a third of Europe's total.

Meanwhile, the US Department of Energy has announced a $180 million "funding opportunity" for four offshore wind demonstration projects, though none is explicitly allocated for floating wind technology. Despite an estimated 4150GW of offshore wind potential, the US has no offshore wind infrastructure as yet, and floating technology may further the cause if NIMBYists can be persuaded that turbines will be placed out of sight and earshot.

Though floating wind turbines do exist, the cautious research-led approach adopted by the US and UK makes sense when you look at the scale of the task they've taken on. Wind turbines over 5MW in capacity are enormous: Enercon's 7.5MW E-126 inland turbine has a rotor diameter of 126 meters (413 feet).

To date, the largest floating wind turbine that has been installed is Norway's 2.3MW Hywind which has a rotor diameter of 82 meters (270 feet). The fact that its development cost is $62 million raises questions about whether the investment earmarked by the US and the UK will be enough to produce a stable floating turbine with more than double that capacity.

The form that the potential floating turbines will take hasn't been decided, but the most likely design is that individual turbines will effectively form vertical spar buoys, each moored by several catenary cables weighted at the ends. This would effectively be an enlarged version of the system used to moor the Hywind turbines—which actually employs additional 60-ton weights at the middle of each catenary cable in order to provide extra tension. Indeed, the next stage of the Hywind project hopes to apply the principle to a 5MW turbine in waters 320 meters (1,000 feet) deep—Norway has large-scale floating wind ambitions too.

An alternative means of mooring would be to adopt a tension-leg system, commonly used on offshore oil platforms since the 1980s. Something like an inverted pendulum, a tension-leg system would see a turbine mounted on a highly buoyant platform with steel tendons stretching vertically down to the sea bed. Research by MIT and the National Renewable Energy Laboratory suggests that 5MW turbines should be feasible at depths of up to 200 meters (650 feet).

The idea of multiturbine pontoons has additionally been, er, floated, but there are fundamental concerns about the cost of such systems, as well as their ability to withstand the extreme forces floating wind turbines would face during extreme weather.

Offshore wind plans are by no means restricted to the US and Europe. The Fukushima Recovery Floating Wind Farm Pilot Project confirmed by the Japanese government last month will initially consist of a 2MW turbine, to be joined by two 7MW turbines by 2016. And by 2020 the Marubeni Corporation plans to build a 1GW floating wind installation off Japan's northern coast, partly funded by the country's tsunami recovery budget. If it goes ahead, the scale of the wind farm would eclipse any sort of offshore wind farm currently in existence or under construction, though much bigger installations are in development, including a 9GW offshore farm at Dogger Bank off England's east coast.

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85 Reader Comments

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  1. Eider wrote:
    jonnybond wrote:
    rmgoat wrote:
    Tom Brokaw wrote:
    whquaint wrote:
    SgtCupCake wrote:
    Fox news reported that these things add to the global warming issue–a problem they have flat out denied in the past. My small brain doesn't know what to think about this. Wouldn't it be better to set up deep sea drilling that have a much higher safety rating than these turbines and a reduced environmental impact?

    I'd like to reply, but you can't seem to write a coherent thought for me to really understand you. Are you saying that deep sea oil drilling and offshore wind turbines are mutually exclusive? Are you saying that wind turbines are unsafe? Which ones, the ones they are trying to invent with this funding? Are you saying that floating offshore wind turbines add to global warming, or to the global warming ISSUE?

    That was a bit aggressive. He said that Fox news claimed that wind turbines contribute to climate change; climate change is something that Fox news is somewhat notorious for outright denying. Ergo, Fox news can't keep their story straight.

    Regarding drilling vs turbines, Sgt: Drilling requires something to drill to, so it's more location-dependent than wind turbines. Further, planet-bound petroleum is a finite resource, whereas the kinetic energy of wind derives from solar, making it effectively infinite. So as whquaint pointed out, while they are not mutually exclusive, the point here is to get the new tech rolling. Your suggestion that it's better to stick with off-shore drilling is akin to suggesting that these new-fangled automobiles are unproven and dangerous and we should stick with horses.

    Eider wrote:
    craigdolphin wrote:
    Interesting. The obvious environmental concern would be for seabirds like petrels and albatross.

    In many places environmental assessments on bird and bat populations are required for construction of new wind farms, and there have been several studies on this topic though the conclusions are still up for grabs. The general consensus seems to be that the habitat disturbance due to the presence, construction and maintenance of the farm will cause more harm than direct collisions with the towers. Making sure that wind farms are not placed near critical nesting habitat or migratory pathways is considered best practice right now (which might seem like common sense from a biology standpoint). There is a fair amount of information out there, even on Google, if you are interested.

    While that seems wise, wouldn't chicken wire or something similar prevent the majority of the direct collisions, without significantly reducing the airflow? Can't hurt to prevent those, even if they're not as harmful.

    Your'e not serious, right? Did you read how large the diameter of these things are? You are not enclosing a 400+ foot turbine in chicken wire. Seriously though birds are going to be a problem for this technology. Some early installations were placed in 'high wind' locations which were also in hawk/eagle migration routes because they like the winds too, to boost them to altitude where they can soar for miles with little effort. More consultaion with biologists and better site selection needed.

    I was under the impression that thermals lifted gliding birds to great heights for little or no energy output I have never heard of high wind acheiving the same effect in birds of prey.

    Birds will migrate when winds are favorable. A good tailwind is essential for birds to be able to travel the vast distances they need with the limited energy resources they have during migration. If a location tends to have consistently favorable winds then you can expect a lot of birds will use the location for migration. If you put a wind farm in a location that lots of birds use for migration, then you put a giant hazard in front of them.

    Everyone chill out. There are thousands upon thousands of wind turbines operating in the world today. The birds vs. wind turbines issue is settled science. Before putting in wind turbines, the locations are investigated for bird migration issues. Heavy bird migration pathways are not used. Done.
    2427 posts | registered
  2. DoomHamster wrote:
    Forgive me. I was being auto-pedantic. Since these wind turbines are not used to mill anything, I would not consider them windmills...I don't need to say it...

    While that does sound like a valid point, were not the wind powered devices used in the midwest to pump water also known as windmills? I'm not sure that milling grain is a requirement so much as an indication of the word's origin.
    3405 posts | registered
  3. AnonymousRich wrote:

    They were used to crush ice, providing the water. Thus they were milling ice.

    At least that's the version I'd like to believe.
    14363 posts | registered
  4. After spending a few years at sea chipping paint, rust, and repainting a few hundred square yards of steel, refurbishing tide gauges, ladders and other items which, in the 1980's were less susceptible to corrosion, I wonder if any of the other commentators here are aware of the truly awesome chemical soup that these installations will have to withstand during their lifetime? The ocean environment is unforgiving and I have not read of the break though in materials science which can, cost effectively, defeat salinity and subsequent corrosion from the marine environment. Turbines on land require annual inspection for damage to their skin due to the leading edge wear and tear.
    The rig "DeepWater Horizon" was due to be sent to salvage before it blew up, others are operating well beyond their scrap date as are ships and many, many barges, If you live by the ocean, you know your car and all metal goods (including your computer) are going to need replacing sooner than later.
    McCay's "Energy without the hot air" addresses some of these issues (see and is quite good about the ROI on some of these schemes. I can't get by the total corrosive power of the ocean when I read of these plans.
    11 posts | registered
  5. These could be useful, we could put cage around and floating windmill farms far away from anyone else, and put Donald Trump inside and let him rant about Alex Salmond and President Obama till he croaked it!
    7 posts | registered
  6. mbrmark wrote:

    Trump would secure a big loan, put neon lights all over the rig, and make a profit selling time shares.
    4154 posts | registered
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