Wind turbines: how big is too big?

Posted: August 13, 2015 by oldbrew in Energy, innovation, wind

Yes and no [image credit: Clean Technica]

Yes and no [image credit: Clean Technica]

Size matters with wind turbines because, as one developer put it, ‘You have the ability to get all the oink out of the pig’. But too big means difficulties arise, such as means of delivery. Wind Energy News investigates.

From megawatts to the size of rotors, everything about wind turbines has been getting bigger.

But even proponents of wind power say they may be reaching a limit as logistics and a lack of social acceptance over their size start to hinder growth.

San Francisco-based Pattern Energy Group Inc. recently announced it will be installing 61 GE turbines at its Meikle wind project in British Columbia, capable of generating between 2.75 and 3.2 megawatts of power. At 180 megawatts, Meikle will be the largest wind project in the province.

The 2.75-megawatt turbine propellers will be nearly 60 metres long, while the tower to hold the rotors will stand at 110 metres. That means the tip of the blades will reach 170 metres high, or a little taller than the tower on Montreal’s Olympic Stadium. GE says they’re the biggest publicly planned wind turbines in the country.

These latest turbines dwarf those of 30 years ago, when the average turbine had a diameter of 15 metres and pumped out all of 50 kilowatts.

Robert Hornung, president of the Canadian Wind Energy Association, said this evolution in size has been critical for the industry’s growth because it allows for more energy to be captured more efficiently.

“Generally, the further off the ground you get, the better the quality of the wind resource. It’s more consistent, it’s often stronger, which means there’s more energy to capture out of the wind.”

He said because wind turbines have become more productive, they can also operate in more places.

“We’re now able to build productive wind turbines in areas where 10 to 15 years ago you never would have been able to do because you never would have been able to capture enough energy to make it worthwhile.”

While the sheer size of the newest turbines are the most noticeable advancement, Hornung said every aspect of the technology has been improving, including rotor shape, the use of carbon fibre for lighter blades, and the ability to rotate the blades automatically to capture as much wind as possible.

That kind of progress has helped make wind the most installed form of energy in Canada in the past five years and driven the cost of constructing wind turbines down by 50 to 60 per cent, said Hornung.

Ward Marshall, director of business development at Pattern Energy, said equipment and computer modelling to optimize the use of that equipment have led to dramatic improvements in performance.

“You have the ability to get all the oink out of the pig,” said Marshall.

But while the latest turbines will allow Pattern to capture more energy, Marshall thinks they may be reaching a limit.

“There’s always this issue of how big is too big.” [bold added]

The logistics of actually getting massive turbines to site are getting more complicated, especially in hillier areas of B.C. and Quebec, said Marshall.

Some turbines are being designed to be built more on site, but that adds to costs, said Marshall.

There’s also the problem of social acceptability and public resistance to large towers on the landscape, said Hornung.

“In essence, how big can you build in an area where people are living?”

But so far those challenges haven’t stopped Canada’s wind capacity from growing, with more than 10,000 installed megawatts today compared with about 300 megawatts in 2003, said Hornung.

“It’s demonstrated that it’s truly a mainstream technology at this point.”

The Canadian Press

Original report: Wind turbines: Realizing diminishing returns as they get huge | Wind Energy News.

  1. p.g.sharrow says:

    “We need to squeeze more out of this PIG”. 😉
    IIRC Sandia Labs built a huge turbine in California for government research in the 1970s.

    The high pressure difference on the blades between the top of the swing and bottom kept breaking the blades off. Their flexing also put too much stress on the shaft and bearings. Thing rarely ran for long and was finally scrapped.

    End government support and they ALL will be abandoned or scrapped. Just as what happened the last time we went through this farce….pg

  2. Ben Vorlich says:

    How does the saying go, Put lipstick on a pig it is still a pig. When the wind isn’t blowing the wind isn’t blowing.

  3. Steve C says:

    Turbines are too big when they can star in videos like the one IceAgeNow featured recently:
    Warning: this is hard core schadenfreude material … 😀

  4. Tiny compared to what they’re building in Paris. 😉

    [reply] a snip at €800-billion 😐

  5. Graeme No.3 says:

    Bernd: I cannot see why it should be started on Bastille Day 2020 when the date on the original article would be more appropriate.

    On a minor matter, carbon fibres are strong but brittle. Not quite the thing to use in blades that are always flexing.

  6. hunter says:

    The French are really into their green revolution apparently.
    The windmill fluff piece is so annoying: No hard questions, no critical review, only stating the rated power, not the actual delivered power, etc.

  7. No matter how much the technology develops and how big they get, the problems will remain low energy density, unpredictability and the need for massive subsidy. Without subsidies the useless things never recover their capital and running costs.

  8. E.M.Smith says:


    I often wondered why that monster was taken down…


    At 170 m that is over the proposed altitude limit for drones, meaning an dones must thread the needle an turbulence near and down wind of them… It’s ever strongly encroaching on the max altitude for ultralight IIRC…

    Maybe bird chopper is too restrictive a term…

  9. ivan says:

    Do the people proposing these monsters actually employ real engineers – engineers that know how to calculate wind sheer forces over that height and actually know what rho (air density) means in the power equation, both on shore and, more especially, off shore?

    I can only assume they are going for size in an attempt to improve the about 25% efficiency of the basic unit. The problem is that it wont. After you factor in the flexing of the blades and wind sheer forces the efficiency will most probably drop to 15 to 20% (it will be even lower for off shore monsters).

  10. oldbrew says:

    ivan says: ‘I can only assume they are going for size in an attempt to improve the about 25% efficiency of the basic unit.’

    As the man said:
    “Generally, the further off the ground you get, the better the quality of the wind resource. It’s more consistent, it’s often stronger, which means there’s more energy to capture out of the wind.”

    Of course there may possibly be ‘confounding factors’ that go against that, but if so they don’t seem to have discovered them yet.

  11. ivan says:

    Generally, the further off the ground you get, the better the quality of the wind resource. It’s more consistent, it’s often stronger, which means there’s more energy to capture out of the wind.

    oldbrew, that is correct IF you raise a small diameter propeller up higher. If you try by increasing the diameter of the propeller you run into the problem of differing wind speeds between the highest and lowest points. This puts extra stress on the blades which usually results in early failure because of fatigue.

  12. catweazle666 says:

    One word…bearings.

  13. Gail Combs says:

    I agree with Catweazle, bearings.

    But what about air pressure differential?

    This nifty calculator shows a drop in air pressure of 0.1 pounds per square inch going from sea level to 57.5 meters above sea level or a drop in air pressure of 0.2 pounds per square inch from the top to the bottom of the swing.

    “the tip of the blades will reach 170 metres high” from sea level you get a drop in air pressure of 0.3 pounds per square inch.

    But what happens when you put one of these monsters on a high peak?
    The highest peak in Quebec is 1,651 meters add your 170 meters that is 1,821 meters.
    A height of 1815 meters is a drop from 14.7 psi at sea level to 11.8 psi or 2.9 psi.

    The highest peak in British Columbia is 4,663 meters add your 170 that is 4,833 meters.
    A height of 4836 meters is a drop from 14.7 psi at sea level to 8.01 psi or 6.69 psi.

    I am not an engineer. I can not do the calculations for converting air pressure to power generated without a lot of study but that looks to me like the higher you go the less actual energy there is to ‘harvest’ from the wind.

  14. tom0mason says:

    “But so far those challenges haven’t stopped Canada’s wind capacity from growing, with more than 10,000 installed megawatts today compared with about 300 megawatts in 2003, said Hornung.”

    I presume those are nameplate values, averaged annualized output rarely hits 20% of that value. However there are the odd few minutes, or maybe even couple of hours when output approaches the nameplate output values. During this time all other generators on the grid have to be restrained to ‘spin the bottle’ mode, and these other generators have to be ready to jump back online to maintain grid stability. All these generator and grid manipulations add extra cost, cost that consumers, either directly or indirectly, have to pay.
    Free energy? Cost effective? Hardly.

  15. Gail Combs says:

    TonyfromOz has really looked into wind power. One of his comments over at Jo Novas is on EROEI.

    Another commenter over at Jo Nova’s made this comment (Sorry I didn’t grab name and link and now I can not find them – darn it!)

    …It is a closely held number but analysis indicates Wind turbines use roughly between 8% and 13% of their actual generated output as compared to their plated and claimed output, drawn from the grid, unmetered and unpaid for, to keep their systems functioning when they are at idle due to no wind or shutdown.

    The actual generated output of the land based wind turbines ranges between about 28% of its plated and claimed generation capacity here in Australia down to about 18% of that plated output in Germany and even less in China.

    The constant reference to a wind turbine powering so many households is a straight out lie as they use the full plated claimed generating capacity of the turbine which it rarely if ever attains and that only on a few minutes time basis, to base those claims on and to promote that lie.

    The real generating capacity of the wind turbines is as above, somewhere around 28% of plate output for land based turbines up to 40% for off shore turbines and down to 18% for Germany’s on shore turbines
    And getting considerably poorer and lower in output as the turbine ages past about 5 to 10 years due to the FRP constructed blade aerodynamic deformation and accumulated faults and wear and tear.

    British data indicates that the economic life of a wind turbine is around 15 years.
    Compare this with Tony’s often made point that a coal fired generation plant will run for 50 years at close to its maximum output before it has to be replaced

    Ref; Energy consumption in wind facilities

    I would think that the bigger these bat-chomping, bird-slicing eco crucifixes are, the more UNMETERED energy they need to draw from the grid to start them up and to keep them moving so the bearings don’t seize and the blades do not deform.

    These mothers are nothing but a massive money pit and who is going to clean up the mess when they are abandoned? The corporate bigwigs grab the money and run while the corporation bankrupts leaving the public holding the bag. How deep the renewable money pit is is not yet known.

    Our children are going to hate us for this fiasco since they get stuck with the bill and the lack of jobs and the clean up.

  16. Gail Combs says:

    The wind and solar con just ‘proves a sucker is born every minute’

    What is interesting to see is the ramped up major push to get pension funds, universities, and Joe off the street to get out of coal (and oil)and buy solar and wind. Meanwhile Al Gore Walks Away From Green Energy

    Now Generation Investment is heavy into medical and high tech.

    Warren Buffett’s Berkshire Hathaway is top investments:
    Wells Fargo & Co — 23.9% of portfolio.

    Coca-Cola Co—- 15.1% of portfolio. (That answers why Coke pushes CAGW so much)
    IBM —- 11.9% of portfolio.

    American Express Co —- 1.1% of portfolio.

    Wal-Mart Stores Inc— 4.6% of portfolio.

    Procter & Gamble Co—- 4% of portfolio.
    And a bunch of banks.
    Suncor Energy Inc — 0.6% of portfolio.
    Phillips 66 (gas stations) — 0.6% of portfolio.
    Chicago Bridge & Iron Company – large multinational conglomerate engineering, procurement and construction company — 0.5% of portfolio.

    George Soros is even more interesting:
    YPF Sociedad Anonima — 3.6% of portfolio.
    vertically integrated Argentine energy company, engaged in the exploration and production of oil and gas, and the transportation, refining, and marketing of gas and petroleum products.

    YPF Sociedad Anonima — 3.6% of portfolio.

    Adecoagro S.A., an agricultural company, engages in farming, energy production, and land transformation activities. It operates through Farming; Sugar, Ethanol and Energy; and Land Transformation businesses. The company is involved in planting, harvesting, and selling grains, oilseeds, and fibers, including wheat, corn, soybeans, cotton, sunflowers, and others; and providing grain warehousing/conditioning, and handling and drying services to third parties… As of December 31, 2014, it owned a total of 257,036 hectares comprising 20 farms in Argentina, 11 farms in Brazil, and 1 farm in Uruguay; 3 rice processing facilities in Argentina; 2 dairy facilities with approximately 6,551 milking cows in Argentina; and 10 grain and rice conditioning and storage plants in Argentina. As of March 31, 2015, the company owned 3 sugar and ethanol mills in Brazil with a sugarcane crushing capacity of 10.2 million tons; and had a cogeneration capacity of 232 MW. Adecoagro S.A. was founded in 2002 and is based in Luxembourg.

    Dow Chemical Co — 2.5% of portfolio. (Dow is heavy into Ag chemical products)
    Endo International —2.2% of portfolio. Generic Drugs
    Zoetis Inc. — 2.1% of portfolio. An Animal health company
    We do not have to worry about EBAY, all these guys have a healthy slice of that company. What these three DO NOT HAVE is heavy investments in the solar and wind industry that they have been pushing so heavily. No putting your money where your mouth is for these three big mouths!

  17. DB says:

    Buffett bought MidAmerican Energy Holdings Company back in 1999. It is now called Berkshire Hathaway Energy. They do a lot of wind because of the tax credits.
    So it was fascinating to hear Mr. Buffett explain that his real tax rule is to pay as little as possible, both personally and at the corporate level. “I will not pay a dime more of individual taxes than I owe, and I won’t pay a dime more of corporate taxes than we owe. And that’s very simple,” Mr. Buffett told Fortune magazine in an interview last week.

    The billionaire was even more explicit about his goal of reducing his company’s tax payments. “I will do anything that is basically covered by the law to reduce Berkshire’s tax rate,” he said. “For example, on wind energy, we get a tax credit if we build a lot of wind farms. That’s the only reason to build them. They don’t make sense without the tax credit.”

  18. oldbrew says:

    ‘A location with double average wind speed has 8 times the power for the same area. Or – to capture the same energy, the blades of the wind turbine in the low wind speed location would have to be almost 3 times as long.’

    But: ‘Higher wind speeds are in higher areas or off-shore, both challenging environments.’

  19. tom0mason says:

    I think I can safely say that as these machines and their electrical systems get bigger the more of a maintenance hazard they’ll become. Stick them out at sea and that cost easily doubles or trebles depending on exact location.
    I suppose you could call that more green jobs, but all it really amounts to is a heap of money going to a very unreliable and inefficient generator/distribution system. A system that will become ever more unreliable as time passes.
    20 year operational life? I wonder what the book odds are on that? Might be worth a bet.

  20. ivan says:

    oldbrew if the GRE site is how they calculate energy of wind turbines then I can see where they get the impossible figures from.

    Yes, their first formula is correct for the amount of energy in a given area of wind for a given time and yes you can calculate that in kWh. The problem arises when you take into consideration the efficiency of the machine converting that calculated energy into actual energy.

    At the best you might get 40% efficiency with a smaller (lighter) structure but that is reduced to 20% or less when you add the massive gearbox and blade weight of larger turbines.

    Then you have to include the electrical conversion efficiency and allow for transmission losses which drops the output even further.

    [reply] offshore maintenance won’t be cheap either

  21. E.A. says:

    “Too big” is big enough to ruin thousands of scenic landscapes, which is already happening. Wind power is just a (very large) extension of the “build, build, build!” mentality Man has destroyed nature with for centuries. The Green angle is very shallow and devious when you dig into the downsides. The visual blight from these machines is unprecedented, which is what makes people so angry when it’s called “clean energy.” Their appearance is the opposite of clean unless one wants to visually drink Sterno. A handful of wind turbines can be interesting to look at but it’s all about scale and acreage spread.

    Wind power has been out of hand for at least a decade and the future is grim for appreciators of the world’s remaining scenery. The authors of Germany’s Darmstadt Manifesto saw this coming in 1998 but money and politics overrode their concerns. They must be quite depressed by now. I cringe every time I see the blasted things on a new horizon.