Discover the Surprising Science Behind Wind Turbine Design for Lower Energy Costs!

[@EngineeringwithRosie]

Keep exploring at brilliant.org/EngineeringwithRosie Get started for free, and hurry-the first 200 people get 20% off an annual premium subscription

[@user-pt1ow8hx5l]

Alright. Still toughed about 'miniRosie' on the way. Congratulations. From Copenhagen.

[@mikefallwell1301]

I really wish they were a more teachers like you while I was growing up. This is how math should be taught. You are an inspiration. I feel so sorry for today's students.

[@custardcatcher5195]

do they make wind turbine blades thin so they dont work very well!

[@protomatala180]

will you marry with me>?

[@jjamespacbell]

Or you could change the equations completely by switching from Wind to Water? Only need to handle the environmental and corrosion problems.why water is 750 x more dense and although generally much slower it is more predictable.

[@loupsuja1877]

I wrote my PhD several years on ago a particular hydrodynamic challenge to having larger and larger diameter tubular towers on offshore wind turbines (the 'ringing' phenomena). As for everyone who has ever written a PhD, spending so many years of my life doing research on the topic gives me the impression that it's the most important issue ever and all wind turbine engineers all over the world should spend at least half their time designing tubular tower with that into consideration. But I won't fall into the trap of writing a KZbin comment just talking about my research! (oh crap, maybe I just did?)

[@user-pt1ow8hx5l]

Well. We're busy in Denmark with those everbigger windblades. Do you think it's a good idea with those 'megawindmillls'. With long blades. And a high tower. Yes or no? (Challenging the ph.d. engineer to simplify?)

[@pixelfairy]

Time for cake!

[@snoopyloopy]

As long as you don't recreate your dissertation here in the comments you're good.

[@neddyladdy]

You have now given us the teaser, and now I need a psychology degree to predict where you will post your first chapter.

[@brianthesnail3815]

I have a PhD too. My job is to finance these. We don't care. It all comes down to one number. Internal rate of Return (IRR). If that is high enough, we will finance it as long as somebody else is taking the technology risk if it doesn't work. Towers, nacelles, blades, foundations, ships, cables. That isn't our problem. I have never seen an offshore wind turbine close up and very few of the people that finance them have either.

[@mydanishgarden3112]

Great vlog Rosie. I'm so lucky to be working in the industry. I have travelled to many of the wind farms and watched the skill of moving the blades, towers and Narcelles. The real understanding of the size is when you get up close to the turbines under construction, the size of the newer turbines is mind blowing. I think you engineers designing these turbines are incredible, as are the technians that are putting them together. One factor that you didn't talk about is wind, turbines are built in places with lots of constant wind. When erecting a turbine you really want to put the tower up in one go and then the blades in one go, the bigger the turbine the longer it takes to erect . The last thing you want is wind, so you need favourable weather windows. The longer the weather window you need the fewer that are available. It will be fascinating to see how the industry evolves over the years to come.

[@stephenkeller1520]

Would you comment on the idea of multi rotor contra rotating turbine hubs. I understand wind turbulence from adjacent wind turbines in a wind farm is a consideration in efficiency. However many propeller based aircraft designs over the decades have successfully used contrarotating propellers accepting any inefficiencies for the advantages of smaller diameter and ground clearance and high engine power absorption. It would also seem that the upstream rotor is adding some kind energy in the form of turbulence to the air stream that the downstream rotor could possibly be designed to take advantage of. The common understanding of wind farm inefficiency due to air turbulence of nearby turbines does seem to get a little more interesting when the accepted use of contra rotating propeller aircraft is introduced in to the conversation.

[@Ralphius86]

Those brief clips of unusual turbine designs at the very end of the video were fascinating! Perhaps worth a future video? I'm especially curious about the airborne types, having previously gone down the wikipedia-research-rabbit hole!

[@eskileriksson4457]

She has a video on the subject.

[@EngineeringwithRosie]

I did a livestream on airborne wind about six months ago. Planning an update and a "proper" (shorter) video on the topic soon. Here's the livestream kzbin.info/www/bejne/aKfHlJmom9isgck

[@kirkwagner461]

I really like the deeper dive into the engineering that you take, compared to other vids on all these topics. Although, admittedly, much of the math goes RIGHT over my head! :D Keep up the good work.

[@EngineeringwithRosie]

Thanks for the feedback! I tried to keep the maths short enough that whoever didn't want to follow that part wouldn't get so bored they'd stop watching! Let me know if I succeeded, or if you'd rather less equations on a video like this. That will help me find a good balance

[@kirkwagner461]

I like the current balance. I get the concepts from the dialog and diagrams, and have enough math knowledge I can see where its going, even if I get lost in the details of the formulas. However I can imagine the more mathematically inclined would get value from the formulas too, and maybe I'll crack some books and try to catch up.

[@judo-rob5197]

I think that you have struck the right balance for a general audience.

[@N3wtt1]

I'm a structural engineer and Rosie did a great job of explaining the math and theory, I definitely wouldn't have been able to explain this as well as she did.

[@alanhat5252]

@@EngineeringwithRosie any audience is a mix of people who like what they see so stay & people who are just passing through, they'll watch one or 2 videos & move on. So the question is, do you like the audience you've got? If you like your audience the way it is just keep the mindset & formulas you're currently using. There's around 4 billion internet users so a few thousand will always follow you but is it the particular few thousand you want? I like what I see so I'm staying. :-) You're showing me more about things I want to know more about & you deliver it with a pleasant voice & demeanor. Thank you for being you.

[@papparocket]

One key parameter you didn't mention is the energy return on energy invested (EROEI or EROI). Not only does the parts get heavier and cost more, but they take more energy to make a large wind turbine. But also the power produced goes up as the square of the disk radius. Also the EROI is determined with the total energy produced over the lifespan of the system. Wind turbines have a operating life span of 20-25 years. So EROI is the amount of energy produced by the wind turbine over its total lifespan divided by all of the energy that went into making all of the parts plus the energy required to transport and install the wind turbine and lastly the energy expended to during maintenance Of course the higher the EROI the better since the amount of energy that is available for use is hopefully many times greater than the energy that it took to make, install and operate the wind turbine. In the limit a EROI of 1.0 as low as one would go since you would only get back energy exactly equal to the energy you put into it. So which increases faster with radius, the sum total of power produced over its lifetime or the amount of energy that it took to make and install thicker walled and taller steel masts, heavier gearboxes and blades. invested

[@schrodingerscat1863]

Many have been found to have a lifespan well under the 20-25 year prediction. Some are lasting less than 10 years due to leading edge abrasion and delamination of the blades. This is especially the case in coastal locations and offshore installations.

[@dianapennepacker6854]

No way in 100 years we are going to print things atom by atom. You all have zero faith in material science! We already can in a lab. Imagine if we could build withcarbon nano tubes and graphene at large scale. Print in on site with robots. Just aren't close for now. This isn't the end of massive turbines. We will go bigger one day for some reason. Control the weather or something.

[@AshesWindTurbineSimulation]

Super cool video. Combining this one with your 'Why do (most) wind turbines have three blades' gives super interesting insight into different challenges and ideas for the future

[@EngineeringwithRosie]

Thanks! Hey by the way, I was thinking it would be cool to collab with you guys for a livestream sometime. I'll get in touch later in the year if that sounds interesting to you.

[@AshesWindTurbineSimulation]

@@EngineeringwithRosie wow what an honor, that would be awesome!

[@EngineeringwithRosie]

@@AshesWindTurbineSimulation great! I'm taking October off, I'll get in touch after that to arrange it.

[@gunnarbech8147]

Great video! Even as a retired rocket scientist I had great pleasure looking at your video. Very pedagogical.

[@CraigFryer]

Another great video. I didn't know you had a PhD as well. Your formal expertise in these fields is far greater than you have let on, so it is Dr Rosie from now on. :) As for the future of wind turbines, if blades that can be assembled on site, arrive in two or more pieces, can't be competitive priced, then I can't see many onshore wind projects having larger turbine blades. As you pointed out, the challenge isn't just going to be the problem of the logistics of the length, but the cross section or diameter at the base of the blade is going to be a major limitation too. Off shore wind turbines has a greater potential to keep getting bigger as the logistics are less of an issue, but the handling cost is surely going to become more expensive as they grow in size. The only question then is what the rate of increase of these costs are compared to the energy returned. Sure the squared vs the cubed does help, but at some point the returns will diminish, however I think we are a long way from that point.

[@barefootbuffalo2024]

From a Vestas guy, I say keep up the good work Rosie! Really like your videos you are an excellent science communicator.

[@metamorphiczeolite]

Wow, such clear and succinct explanations! Another excellent video. Thanks, Rosie.

[@QALibrary]

A video I was very much looking for

[@barriedear5990]

You had me at cake. Very interesting video.

[@Koro2810]

Thanks

[@albertoplm]

Excellent video. Extremely valuable all the references provided with the description.

[@Bennyboy-dog]

Another excellent and informative presentation Rosie. I saw an interesting development in wave power by a company here in Australia. The Wave Swell Energy Uniwave 200 is apparently operating off the coast of King Island and generating 200kW - it is a form of windpower generated by waves. That looks interesting too. Perhaps you can take a look?

[@EngineeringwithRosie]

I saw that too, looks cool! I talked with those guys a while back when I made a few waves energy videos, they weren't at a stage they wanted to talk about their tech publicly at that time but I'll try again. I would looooove to visit King Island, and plenty of other video possibilities on the island besides wave energy.

[@hellsing56666]

Thank you for the dive in wind turbine engineering, really interesting.

[@jerryrandall9251]

Great video! Really nicely explains the tradeoffs. One other benefit for big turbines particularly onshore is in wind farm design. If you have bigger wind turbines, then you can concentrate more power on the windiest points on your site, wake efficiency improves and land costs go down. So even if the cost of energy from bigger turbines stops decreasing at some point, bigger turbines could still reduce wind energy costs overall.

[@dansshop]

Very good. I play in small (micro) wind energy ~ I do a bit of writing and sometimes teach workshops on the design and build of small wind electric systems. Size often comes up and I always have to point out the advantage of height (which often comes with larger machines) ~ and the fact that energy harvested is related to the cube of diameter while the weight of the rotor, and the alternator is roughly related to the cube of the diameter. With small, direct drive alternators I usually use about 8x the magnetic material and 8 times the copper, if I double rotor diameter. (4x the power at half the rpm) I love your channel.

[@donmacquarrie9161]

should build one of these... kzbin.info/www/bejne/oarIZ3R8n76Ur6c

[@retro-spective3403]

Great videos on wind turbine design, very informative. I particularly enjoy the ones on VAWT’s as I got involved in a VAWT start up after I retired, but subsequently left the business for reasons outlined below. Without giving too much away wrt proprietary design which is being patented, we were trying to boost power output by manipulating (increasing) native wind speed impinging on the blades of an H blade VAWT (though it could also be applied to spiral blades). Ref the wind speed power equation, the two easiest elements to modify to increase power are obviously swept area and wind speed. In one of your VAWT videos you cover why increasing VAWT swept area comes with increased costs and technical challenges, and why the Betz limit effectively rules out trying to become more efficient than HAWT’s as a credible performance improvement avenue. So that leaves wind speed, which because it’s cubed in theory offers by far the best chance to increase power output. However, increasing native wind speed requires external intervention / interception and we found via patent search numerous examples of VAWT designs employing external devices to do this, eg, cowlings, Venturi’s, funnels, diversions, channels, etc, but what was also obvious was that none of these seem to have ever been effectively commercialized, suggesting they either don’t work or more likely don’t work well enough to warrant significant development investment. As we progressed through TRL design and testing we did find some wind speed increase that would require VAWT / blade design optimization to capture maximum benefits, but it wasn’t enough to likely challenge and replace the dominance of HAWT’s on the market. HAWT’s dominance effectively meant breaking into the wind power generation game would require significantly more power (wind speed) increase than we had seen to warrant an investment risk on a new tech start up as opposed to a less risky ROI through simply making bigger HAWT’s! After much consideration it was the observed experimental limited wind speed increase potential, slow and expensive pace of development and extreme business challenge that caused me to make my decision to leave, but it was still a very interesting project to be involved with. The business is still working on trying to improve the concept! So this brings me to my technical question to you, in your opinion why do you think attempts to increase native wind speed before hitting the VAWT all seem to fail, or at least not work well enough to warrant further investment, and finally achieve commercialization? Maybe a good topic for a video?

[@jamesknapp64]

This one just popped into my feed, really well done and great insights and analysis.

[@75blackviking]

I love your channel, Rosie! You have great content. I learn so much every time I watch your vids.

[@arkapravobandyopadhyay9851]

Thanks Rosie. That is the least I can say. Glad that I found your channel.

[@ChrispyNut]

Likely be "floating" turbines to reach those 50+MW figures. Gets them up high and negates many of the transportation problems. Just need material science to resolve the carbon nanotube at scale problem. Super easy, barely an inconvenience. 🙂

[@robertcampomizzi7988]

9:25 I've always observed this while driving... I wasn't sure if it was actually what I was seeing. My Dad was an engineer and he 'didn't know'... THANK YOU. I can put this to rest!

[@TorkilZachariassenTZNG]

Who needs Brilliant, as Rosie is nothing but brilliant? 😁

[@carlbrenninkmeijer8925]

Thank you for this brilliant Video. Dr. Hansen published a paper in which he and co authors mentioned Super Storms. I concluded that off shore windparks must be able so withstand Hurrikane windforces. Larger fields with not too tall towers can withstand extreme weather and protect coasts by breaking waves and softening winds. But my remark should not do injustice to your extremely bright work and presentation.

[@eastcorkcheeses6448]

There's a you tube video somewhere about the world's largest mining dragline, it was perfectly feasible to build and operate , but the maintenance costs were off the scale because everything was just too big to comfortably service - so downtime was huge , It was abandoned -

[@stauffap]

That was super interesting! Thanks for sharing your insight with us!

[@Shermanbay]

One thing you didn't mention is the increasing height related to airspace. The FAA already imposes limits on how tall a structure may be based upon the distance to the nearest airport. At some point, the possibility of conflict with aviation may become more important than the physical stresses on the blades or towers.

[@ptonpc]

I remember reading a few years ago about magnetic gearboxes, the idea being they were supposed to be simpler to maintain, were lighter and had fewer power losses. I wonder if anything came of it?

[@Ikbeneengeit]

Beautiful engineer overview, thanks!

[@swt-gdesign1859]

Great video!! Very educational!! . You said something about new designs and I agree with you there too. There’s a wind machine design out there that instead of going up in the air is going down to the ground , in fact it’s going to be under ground. The designer thinks this machine could produce hundreds of megawatts per machine and produce power 24/7. Could be installed near the consumers, thus saving on transmission lines. Very interesting design. It is a super wind machine.

[@peterpicroc6065]

I saw somewhere that Vestas has some cooperation with a company that makes segmented towers out of wood. Solves both the diameter problem and the issue of lots of steel being needed for towers.

[@andyroid7339]

Another great video Rosie!I find turbines fascinating and have pondered this question before. Two thoughts came to mind whilst watching the vid: - might it be possible to construct a pressurised blade? In the same way that a paraglider's wing stays formed during flight, a pressurised blade (with a compressor near its 'root' and electrically powered) would help maintain the form of a partially 'flimsy' shell. This could reduce manufacturing and transportation costs. - Thinking about when the wind is not blowing, is one large inoperative turbine better than 5 smaller inoperative ones? Or is it better to spread the risk of no wind?

[@drecksaukerl]

Hm, a pressurized blade seems like a good idea, until the pressurization system fails. In the 1980s, there was a trend of building stadiums with super lightweight membrane roofs weighing a fraction of conventional truss supported ones. They were held up by a slight overpressure in the building and were of course much cheaper to build. Eventually they all failed due to environmental conditions and/or failure of the overpressurization machinery. All but one have since had major structural work done, aka explosive demolition. Great in theory, not so great in practice. There's also the problem of pumping air from a stationary compressor into rotating structures. I'm a structural engineer, not mechanical, but it doesn't sound easy.

[@andyroid7339]

@@drecksaukerl Thanks for your answer! My thought was that the compressor for each blade is built into the base of the blade, electrically powered by a 'ring' electrical connection through the turbine's axis and possibly also the pitch mechanism. Re: compressor failure - I guess this would depend on air leakage through the blade and whether the brake mechanism could halt the blades' rotation quickly enough to prevent serious damage and if a pressure connection to adjacent blades would be worth consideration.

[@bradkark]

I always enjoy your video’s. I have often wondered if we will get to a point where a manufacturer will “lock in” to a particular design and if there would then be scope to decrease cost due to economy of scale?

[@BillMSmith]

Excellent as always. I enjoy your forays into the formulas and principles without tipping over into total geek speak. You tread that line well. How to different soil structures figure into foundation design? More importantly, does it significantly affect the cost. BTW, any reason for eating cake yet?

[@EngineeringwithRosie]

No celebration cake for me yet, though being 41 weeks pregnant has led to a few cake cravings I will admit (assuming that's what you meant by the cake comment!) And I'm glad you thought I got the balance right between showing the important formulae but not making it an engineering lecture. It's a tricky balance! I don't know a whole lot about foundation design, but that could be a cool topic for a livestream if I can find an expert to get on as a guest. There have been a few foundation failures in the news recently, it works be nice to find out more about what that's about.

[@modernsolutions6631]

I would love a 50 min video where you go over the data of one particular type, curve fit all the laws using real world data and just run and discuss one of these optimization models.

[@theelectricwalrus]

I'm eager to see an "offshore VAWT" video if you've got one coming up! There's a lot that's different and I'm curious how it could impact the designs and sizes

[@EngineeringwithRosie]

You're right, I should do a video like that. There are so many new companies trying to get into that space.

[@ralphcrawford9741]

As an electrical engineer with some structural and heavy equipment background, your math and graphics ratio were perfect. What a great example of a typical engineering problem - optimizing many design variables. And scaling is such a wonderful way to prove design concepts but can be problematic in certain engineering areas such as fluid dynamics if I recall. Scaling, and ignorance of resonance, (as someone else commented here), was the downfall (literally) of the Tacoma Narrows bridge.

[@ferdyhengeveld3050]

Excellent video, Rosie. And I must say, being a Dutch guy with 24y in the industry, that the anniversary speech topic, including embarrassed laughter, is not restricted to the Danes.

[@EngineeringwithRosie]

Do you guys do the cake too? Or Stroopwafel perhaps?

[@Tore_Lund]

How does foundation size scale? Not only does a bigger rotor increase the wind load, but the higher tower increases the lever force on the foundation? Will floating wind turbines mitigate that?

[@kinguq4510791]

Thanks, very interesting and well presented. Having lived in Norway for several years, I really get the cake and speech thing!

[@kensmith5694]

What rules out making the tower with cables. Cables allow the tower to mostly deal with the vertical force while the cables keep it standing up. This seems a natural way to go taller without making things too big to go down a road.

[@ragaloft]

Thanks Rosie. Your video got me thinking (the best compliment 🙂) is the air mass of anabatic and katabatic winds sufficient to support power generation? I live near a coastal mountain that has a cliff face with tremendous winds (in both directions) I sometimes wonder if very large axial fans of efficient design, bolted to the cliff face, could overcome the tower issues?

[@Boukevx]

Hey Rosie, great overview. Check out the Lagerwey self climbing tower for another method to build high towers without the need for a large crane. Lagerwey has been taken over by Enercon so they have that technology now. This method of installation has already been proven on many installations in the Netherlands and in Europe.

[@harrybarrow6222]

Excellent video! Thank you.

[@Gnoccy]

Respect for your career. That's pretty cool.

[@kenoliver8913]

A great presentation. I think you could, though, perhaps have made the point that the optimum size for offshore and onshore turbines is very different because of the fabrication and transport challenges of very large blades for inland ones (shipyards are designed to fabricate huge structures, and you don't need to worry about bends and clearances on the water). For inland ones, therefore, the optimum size is mostly set by these constraints while for offshore ones it is set by the scaling issues you detailed so well here. Of course offshore has its own expensive issues (eg getting the power back to shore), but the point is the size considerations differ.

[@EngineeringwithRosie]

I agree, and I thought I did say that! Not very clearly obviously...

[@philv3941]

really cool explanation, what i miss at the end of the vid, is something like a curve showing we could not have reach more than N kW with older fiberglass wing design, without raising the cost by MWh produced, and the same with the Carbon Fiber. I left the video with no clear clue of what will happen ? more than 16 MW by pole, or are we today at a maximum ? As we know we have nowadays nothing really best than epoxy/carbon fiber, it could have led to a max, where higher means a higher MWh ?

[@hermannrochholz1701]

Hello. Good, but there are some little points - hmm: "Kevlar" is Aramide. And under pressure it's much worse than under tension (The same for HM-Carbon fibre not mentioned here.) Next important point: The gearbox growth is exactly by cube with diameter: If you double all dimensions of a WT, with a constant tip speed you end up 8 times of the torque. That's in fact the same machine (except minor aerodynamic incluence in this sizes- bigger is better - as in real life). So if you have the direct-drive Enercon E126 with 400 tons of Nacelle- try to made a 200 m rotor :-) A rough estimation ends up at 2000 tons. I assume you'll kill additionally all the frequencies of the tower. Therefore: gearbox- machines- maybe. But direct drive has stopped already. And to compare strong-wind and low-wind-machines isn't as easy. That's apple with pairs.

[@CanusDirusx]

Another great video! Thank you.

[@lint2023]

Incredibly interesting. Thanks.

[@guotaozhang4968]

What is tilt angle for larger rotor at end of this piece of video?

[@yvanpimentel9950]

just a thought, what you build a hub with a Long interconnected arms like a bicicle so you use the same blade but with a 15 to25 meters more, and you could even have a different sleeve in the first part so the pitch can be adjusted in the Ruth and the tip independent, transport will be easier and it will work in a wider range of wind speed.

[@sriramulunakka4348]

hi mam ,i watched the entire playlist on wind turbine design .thank you for sharing your valuable knowledge to us.(theoretical and practically you shown us).but i have small doubt at stall regulation , why we need to reduce power at high speed with stall regulation ? I am waiting for your reply thanking you.

[@colingrant321]

Loved the video. Subscribed for more. Wondering how often you need calculus verses pre defined formula?

[@Pete856]

Most calculus/algebra using in engineering are pre defined formula....if it works, then no point starting from scratch just to get the same result.

[@alanhat5252]

A few thoughts: Are these very large machines already a 'hazard to navigation' for aircraft & if not how big can you go? What do you do about different wind speeds & directions at different heights? Can you end up with a machine that's big enough to launch satellites off it's blade tips?

[@udishomer5852]

Onshore they are a hazard, at least for small recreational aircraft. Offshore its not a problem as no aircraft flies at 200m above sea level. Commercial aircraft usually cruise at 10,000m above sea level.

[@stephenhill458]

Really interesting video - thank you for the formulae behind the factors on either side of the tug-of-war. Now a question. Why do turbines all seem to have 3 blades? Without one blade running into the turbulent air of the preceding one, couldn’t more energy be ‘harvested’ with 6 blades (or 4 or 5) without needing longer blades (or higher towers)?

[@EngineeringwithRosie]

That was one of the very first topics I covered on this channel 😀 kzbin.info/www/bejne/nGTLmHVjZdeDhas In a properly-designed turbine, there isn't any air slipping through the gaps between blades, every air molecule has some of its energy extracted.

[@sergiokieri3137]

Solid video, subscribed.

[@spinnymathingy3149]

A question please 😊 I’m mystified At how fast the blades go, the outer portions many hundreds of KPH . I’m wondering how this intense speed of the outer portions of the blade can actually be helping generate power, in my way of thinking it’s a burden on the system as the prevailing wind is vastly slower ? (My humble comparison is only with cars, where wind resistance when you go over 200 kph is like hitting a brick wall) Thanks

[@jamesdubben3687]

Fun design talk. Counter rotating blades? Too much vibration?

[@tsbrownie]

Or maybe blades will change. Airplanes went from 2 blades to 3 to 4 to 5 as more power was applied. Then there's exotic designs like scimitar blades. Maybe wind turbines will do something equivalent. And generators could go with superconducting coils/magnets. Lots of room for improvement.

[@DavidOfWhitehills]

Three blades is optimum. As l understand it you have to allow the wind to pass through - more blades and the wind will take a path around. Anyway there's actual experts have made videos about this.

[@tsbrownie]

@@DavidOfWhitehills I've watched those and more blades also mean lower speeds for same torque, therefore quieter, and less air speed difference between the top and bottom blades.

[@DavidOfWhitehills]

@@tsbrownie So why aren't they being built with more blades?

[@tsbrownie]

@@DavidOfWhitehills Why were the first aircraft 2 bladed? Same with ships screws. Look at the development of submarine screws. These things usually boil down to current technical capability and costs. Those change with time.

[@DavidOfWhitehills]

@@tsbrownie Hmm. If you obstruct the wind you lose the wind, it will just go around or over.

[@geraldhoag5548]

How about a discussion of wind turbine other than blades. I have seen vertical helical wind turbines, horizontal system on roof tops and barrel shaped wind generators. The barrel shape I most recently saw was used in Okinawa Japan and reportedly survived a direct hit from a Cat. 3 Typhoon. Lets look at more options for various condition where a blade system might not be appropriate.

[@enemyofthestatewearein7945]

Great explanation, I think most systems have a 'sweet spot' size wise and it's not always just about what's theoretically possible. Something I'd therefore be very interested to know is what are the life limiting factors and components for wind turbines? Currently life expired turbines usually get completely replaced (re-powered) after 20-25 years because larger and more efficient turbines have become available since they were installed. This does obviously increase efficiency of the particular wind farm but it's arguably not a good use of carbon intensive materials (or costs) to do a complete replacement. So it would be interesting to know what will happen once most turbines achieve an optimal sizing, as suggested. Could these turbines be maintained and run indefinitely? What parts would need to be replaced, and what parts could be reused? Foundations and grid connection are a major part of the cost, so I would guess big savings should be possible if these can be reused, and both should be good for 100+ years.

[@srw_cricket2976]

Hi Rosie, have you seen the recent Harmony Turbines spot on Disruptive Investing here on YT? They have some very interesting developments on their version of a Savonius Vertical Axis Wind Turbine. Well worth a watch.

[@plinble]

Add more blades, and put on sliding tips, if the wind is lighter they go at the end? With strong wind they are nearer the axis.

[@Sailorman6996]

Another aspect is the windspeed every cross section sees. Near the hub - most if not all design is for strength and are probably not adding power. Further out is a transfer to an actual aerodynamic profile while the windspeed crossing the blade is not much more than the wind a pixed point sees. But at the wing tip the wind across the blade is extreme, I imagine it may be close to what a aircraft have. At some point of scaling turbine blade up - I think the wingtip is more drag than adding power. What do you think?

[@ASJC27]

As she mentioned in the video, the rotational speed is reduced with increasing diameter, so the tip speed stays the same for optimal aerodynamic performance.

[@jimmyjohnstone5878]

What happens to the air ( wind ? ) pattern downwind of a large wind farm ? Are there any local climate effects ? Any research done on this ?

[@Runoratsu]

Wasn‘t there also a problem with blade tip speeds getting into the transsonic region at some point?

[@salec7592]

09:23 Bending due to self-weight For the ascending blade, isn't its weight compensated (and exceeded) by very aerodynamic lift turning the turbine? But then again, the descending blade suffers combined forces of its own weight and aerodynamic force. Perhaps steering the angle of the blade on its way down could keep this force constant, to reduce dynamic stress? To reduce weight of a blade, as well as work around the transportation problem, don't build them as solid structures. Perhaps you could use the trick flying insects use in their wings: supporting skeleton made of a mesh of tubes filled with pressurized liquid. Some of the insects (e.g. dragonflies) use liquid which hardens after the wings are fully unfolded, and so could wind turbines, as there is usually no need to retract the blades (... until the end of their operational life, that is). Another option would be blades made as inflatable structures. Related to that, inflatable blades could be filled with lighter-than air gas to achieve neutral buoyancy in air. Since they are connected to the hub, the blades can't catastrophically fail like airships did, but construction and operation must make provisions for any case of sudden reduction or loss of lift, etc.

[@mitchberkson4235]

Isn't the additional fatigue caused by the greater flex of a bigger blade offset to some degree since it is rotating more slowly?

[@rickperalta1921]

Dr. Barnes, Has anyone investigated toroidal blades? It should be more efficient and structurally stronger. Fabrication on site can avoid the critical transportation issues. Thanks for being a voice of engineering clarity!

[@nakrul987]

Could the blades have pressurized elements to provide more stiffness at reduced weight?

[@Tjeran]

How does the operational window for wind turbines change with increasing size? My guts tells me that with larger size there's more mass to rotate and the amount of energy needed to initiate rotation from standstill is larger. I would therefore assume that you would need higher wind speeds before it could start. Is this correct?

[@dket2571]

Wow, thanks Rosie. Much to think about....

[@jonathanrabbitt]

Given that the wind speed increases with the cube of hub height, what are the constraints that currently dictate tower height? Why can't the lower courses of turbine towers be constructed of segmented elements to remove the diameter constraint? Is there a case for tripod designs for the lower part of a wind turbine, to improve economics of foundation design?

[@arturoeugster7228]

wind ground turbulence boundary layer 1/7 power law. fairly independent of Reynolds number, over a long ground plane.

[@williamarmstrong7199]

A Question? why do all the turbines turn the same way. The wind disturbance behind each turbine last for about 1.5 Km if they turned in different directions surely this would be less as in counter rotating propellors for aircraft?

[@davidanalyst671]

this was a lot more interesting than i thought a phd video could be. My only question is that you didn't mention upper atmosphere winds. I read that the main reason why turbines are getting bigger was because they get to reach higher velocity wind higher up in the atmosphere. you approached this video without any consideration that wind will change direction, change speed, or on average have higher wind speeds farther off the ground

[@peterpicroc6065]

That was explained at 2:56.

[@harrybarrow6222]

I imagine that blade tip velocity is also a limiting factor . What happens as it approaches the speed of sound?

[@harrybarrow6222]

Ah. You answered my question.

[@markjmaxwell9819]

l would imagine crane size is one of the biggest factors that will dictate wind turbine size also transport will play a part. Cost and manufacturing versus output in MW and maintenance factors such as parts replacement will play a role. l really enjoyed this one you went into small detail and you showed confidence in the subject including ways to build bigger. Public opinion will also play a part going forward into the future. The positions of wind turbines and solar farms is a contentious issue in Australia with size annoying some people also. l prefer as much power generation in one location as possible to cut down on public hostility and increase efficiency... The bottom line is still cost versus MW no matter how big the turbine, also the ability to recycle parts is coming into play at the moment....

[@dnbeuf72]

Great video. But how does this work for vertical blade designs? These have different scaling behavior, is there a size where these make more sense then horizontal turbines? Especially off-shore?

[@EngineeringwithRosie]

The square-cube law is mostly going to apply to VAWT components too. Depending on the specific design, the equations could change (e.g. if the blades are fixed on both ends) but you'll still get power increasing with the square and mass increasing faster than that. The larger VAWTs that were around in the 90s we're already struggling with scale, there were a lot of failures and they were mostly using guy lines to secure the top of the tower which isn't easy to replicate offshore. So I expect more not less scaling problems with VAWTs though I haven't studied it in depth. A few commenters have suggested floating VAWT would make a good future video topic and I agree.

[@AndrewTSq]

I would want to know how these wind turbines effect our enviroment also. They must slow down our natural winds? And it will become hotter since the wind will be moving slower? Somewhere the energy tjese wind turbines takes must affect something?

[@kalicom2937]

Edit - correcting typos. Sorry but I would have thought grid connection cost per MW of capacity of an array of turbines drops if the array uses higher capacity turbines. I.e. if you have 10x1MW turbines compared to 1x10mw turbine you have 10x as many connections...... Can you explain why this is not the case?

[@enemyofthestatewearein7945]

That's true to point but since windfarms are normally wired in strings it's not entirely linear, nor is the cost of switch gear and transformers since smaller units are made in much larger quantities so benefit from economy of manufactured volume. I would suspect that foundations have a much more significant bearing on cost savings when using fewer, larger turbines.

[@StoianAtanasov]

Why as the sweep radius increases and tip speed remains constant, the number of blades is not increasing? Thanks for the great video!

[@peterpicroc6065]

I wondered too!

[@atanacioluna292]

Here is a different direction for wind technology: Pluvicipia creates wind inexpensively and with primarily positive side effects. In that case, it seems big is unnecessary: Produce faster currents onto your field, the energy sources, potential temperature, is better than free, using it helps to cool the planet and absorb C02, as well as produce water and food, etc. Sounds too good to be true because it is the energy source for the next era in human development. Check it out; you will love it. It will return on the market soon; I'm trying to complete numerical modeling before republishing the revision. At this point, the best I got is prior mathematical models and quick AI design revision. But it will be out there again soon.

[@stephenbrickwood1602]

very good work

[@eveningecho5334]

Is what I would term as “clean airflow” a factor in the size increase? Ie, if wind has already passed a turbine the air is now tubulent and using that on another turbine is less efficient at capturing energy(I believe), where doubling the size of the first turbine to get the desired double output would be more efficient way to harness clean air. Does that figure in the business case or is my turbulent air thinking some old fashioned idea I read somewhere and is no longer valid?

[@nigels.6051]

There is always going to be less power in the wind downstream of another turbine, even if you are 100Km downstream; there is limited power in the wind. But turbines are normally spaced out sufficiently that actual turbulence is not much of an issue. I do wonder at the shape of new floating wind farms though, if the turbines are floating then you can place them in any layout, water depth not being an issue, so why are the farms always blocks of turbines instead of long rows facing the prevailing wind direction? I guess it keeps cables shorter, but other than that...

[@eveningecho5334]

The floating wind farms are anchored to the seabed with stay cables so it’s just less of an engineering challenge to build at those sea depths. The spacing of wind turbines to mitigate turbulence is limited by the area available, onshore or offshore you can’t just plant your turbine anywhere you like, offshore you need to respect shipping lanes, onshore you must have title or land owners permission so you are always going to want to increase production capacity within the physical constraints that you have and it strikes me that fewer plant within a confined area meeting new production targets is surely a driver for larger turbines given that you can’t pack rack and stack them within existing real estate. More curious if the current designs have rendered such turbulence a non issue, just like turbulent water being used for hydro generation, perhaps there is an energy benefit if the turbulence can be captured.

[@suunraze]

Wake effect modeling is a very real and important component of wind farm design. You optimize the number and configuration of turbines such that you maximize total capacity per land area while minimizing wake interactions and component use (another tug-of-war). This is a multivariate algebra problem including costs of components, installation, operation, interconnection and land. Distance between turbines can be listed in terms of "D", the diameter of the swept area. So for example, if your rotor length is 100m, D is 200m, and turbines 1000m apart would be a "5D" spacing. When I was studying, spacing somewhere between 5D and 10D was generally considered optimal, depending on many conditions. Percentage of power lost to wake effects is a function of spacing. To directly answer your question, assuming you are spacing your turbines at some fixed multiple of D (and therefore keeping a fixed percentage of power lost to wake effects), the number of turbines per land area would scale with the inverse square of D (since the land area has two dimensions). Therefore, the total swept area (proportional to square of D) per land area would remain constant. At least, I think that's how it works out. This puts wake effects in the "audience" category, I believe.

[@paulbrouyere1735]

I visited Vestas Denmark when they had their prototype 1,5 MW windturbine under construction. Visited 2 other manufacturers, too. I asked the same question to the engineers. At that time the answer was ‘about 5 MW’. We know now that Vestas largest is about 15 MW. Can it get bigger? Probably. Is it an economic optimum? Maybe

[@bernardfinucane2061]

Could you stiffen the blades by running wires between them?

[@markgrayson7514]

I love your content, especially about wind. Which type and size turbine saves more birds and is quieter at the ground? I recall you once said that tower height is minimized relative to blade length, and a longer blank base tower section costs money with no return. But the longer that length, the less noise for people and if I recall, less bird strikes. Could those additional costs be budgeted into projects, maybe from other sources of funding? From today's video, could worn giant turbines get shorter blades of new designs with minimal loss in output, mitigating current problems? Maybe address mitigation through upgrades? Thanks!

[@EngineeringwithRosie]

Noise is related to blade tip speed, which doesn't vary much with size. Offshore towers are kept pretty short, but onshore towers are usually as high as they're allowed to be, to reach the better wind resource. I haven't seen any proper bird studies that looked at tower height vs bird fatalities. I assume it would vary a lot depending on the landscape and bird species. I have been intending to do a video on wind turbines and birds ever since I first started this channel, I really need to just get that done!

[@EngineeringwithRosie]

Oh and your last question, about swapping out old worn blades for new shorter ones. No, that never happens. When old turbines are refurbished they'll just repair/replace like for like. There have not been such large efficiency gains that you could use a noticeably shorter blade. Sometimes old wind turbines are repowered at the end of their design life, but if blade length changes it is invariably to longer blades to get better capacity factor (generate more power at slow wind speeds and therefore more energy overall).

[@hamjudo]

That reminds me. I have to finish putting together the system so birds stop running into my windows. As everyone should know by now, windows kill many more birds than wind turbines. Birds evolved along with trees, so they know how to avoid branches. Windows are new to them, on an evolutionary time scale. 3mm diameter paracord spaced every 100mm has been shown to be good enough to prevent almost all bird strikes. (Doesn't stop cardinals from attacking their own reflection, or help when a bird is surprised by a bird of prey and they aren't looking where they are going.)

[@EngineeringwithRosie]

@@hamjudo yep, buildings, cats and cars cover nearly all human caused bird deaths. Climate change is a further threat. Wind energy is definitely an overall good for birds, but I still think we need to do what we can to avoid harming birds, especially endangered ones.

[@peterpicroc6065]

Wind turbines distributed throughout a country reduces the need for big power lines. Power lines kill large numbers of birds.

[@zazugee]

for future, how about 1km high wind turbine, or an artificial hurricane someone already suggested something called "atomospheric vortex machine" to create an artificial tornado to use waste heat from powerstations we could make one as a more efficient solar tower

[@golamsabbirrifat6561]

Axial Flux permanent magnet generator vs Doubly-fed induction generator which is best for wind turbine? Please reply

[@DanielinLaTuna]

When I was still in the power industry (Los Angeles, California) I had to decipher a term from Palo Verde nuclear station (LA is a participant): BOP - turned out to be “balance of plant” Nuclear engineers and Navy people would already know that

[@incognito253]

I'm at 2:30 and going to make a couple predictions to see how they bear out with your analysis before watching the rest: 1 - turbines will continue to grow in size for some time as our materials science improves because of the efficiency returns of making turbines bigger and taller 2 - turbines will hit the tyranny of the rocket equation and the same kinds of problems as megafauna as the ever-increasing structure sizes demand more structure to hold the structure up which demands more structure to hold up that extra structure, amplification of resonant forces will come into play....TL;DR - at some point, the material capabilities of the turbines will start to hit efficiency limitations where you CAN go bigger but it will become more expensive in LCOE to shore up such colossal turbine structures than to just build 2 turbines. But we're not there yet. 3 - eventually the advancement of wind harvesting will shift towards finding ways to make turbines (or non-turbine) megastructures that are more and more efficient at harvesting wind as we'll hit practical efficiency caps at just building bigger and bigger crap.

[@incognito253]

I'm no engineer but I don't think I did too bad. I think you did a much better job than me though!

[@toxicpadda]

What about designs that are direct drive, with the generator has been designed with more poles so that no gearbox is needed.

[@kinngrimm]

How about how small where it still might make sense to use them, maybe for private households. Weight about weight, maybe some day we have them up in the clouds or above where they do not disturb our views. Bladeshapes seem also rather important. While we see always the huge once. There are now solar planes which can stay 24/7 up in the air above the clouds. Would a similar thing be possible with windturbines? Ok and now i am going complettly of the rails ;) , a small while back some experiments showed that lasers could provoke lightning around the lasers. Could that be used to tab into that energy?

[@HeDzsz]

the dutch company Lagerwey make wind tubine towers that consits of sections. eliminiating the size limit of tower diameters.

[@andycoomber6159]

Why do all? turbines have 3 blades? Could you get the same performance from 4 or 5 ?smaller blades on the same hub. Thank you.