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Floating wind turbines could rise to great heights

135 points by prostoalex 5y ago

Symmetry 5y ago
I wonder if balloon wind turbines might not be a better approach in those circumstances. You have to accept smaller blades but I'd think the other advantages would be worth it.
- flavius29663 5y ago
  Wind turbines output grows with the size of the blade (it's squared). http://large.stanford.edu/courses/2011/ph240/parise1/ http://large.stanford.edu/courses/2011/ph240/parise1/ edit: When you take into account that the blade size increase means a higher tower (and thus higher wind speeds), the increase is more staggering, because wind speed is cubed in the final output: > Combining the effects of height and blade length, doubling the height and doubling the blade length will result in an increase of power over 22 fold. This is why companies try so hard to build bigger blades, higher. Current blades are just massive https://cdn.vox-cdn.com/uploads/chorus_asset/file/10382023/Wind_turbine_heights.jpg https://cdn.vox-cdn.com/uploads/chorus_asset/file/10382023/W... The wingspan of a 747 is 68 meters. The newest GE turbine has a diameter of 220 meters, each blade is 107 meters. One blade is 50% longer than the whole wingspan of 747. You can fit 3x747 planes inside the area swept by a current turbine. This is why Google's Makani project never took off...I really hoped for that project to succeed, it was very cool, but there is no way to compete with the bladed giants. edited to address cjbest and baq valid comments
  - cjbest 5y ago
    I think you meant it grows as the square of the blade length (and the cube of the wind speed) From your link: > Thus, the power passing through the blades of the turbine, and thus in turn the power of the electricity the turbine generates, is proportional to the square of the length of the blades: a doubling of blade length leads to a quadrupling of wind power passing over the blades. Doesn’t change your conclusion of course. Thanks for the interesting link!
    - flavius29663 5y ago
      you're right, and I roughly knew that, I just didn't knew how to express it well enough in a short manner. When you increase the blade you also have access to higher winds, so the total output is much much bigger. I was focusing on the quote below and I didn't knew how to express it better. > Combining the effects of height and blade length, doubling the height and doubling the blade length will result in an increase of power over 22 fold.
  - baq 5y ago
    > grows exponentially with the size of the blade (it's cubed). sorry, couldn't resist nitpicking. you're contradicting yourself here :)
    - adrianmonk 5y ago
      If only it were exponential... build one REALLY big blade and power the whole earth.
  - kitd 5y ago
    The newest GE turbine has a radius of 220 meters, each blade is 107 meters. My last maths class was decades ago, but ... 'diameter'?
    - flavius29663 5y ago
      ha, I think I need more coffee this morning. Or maybe i was just too excited to type that out, finally something I know a little bit about on HN
- mLuby 5y ago
  I did a research project on this. Aerial wind turbines have two key advantages over terrestrial ones: access to steady high-speed winds at altitude, and limited ground footprint. But floating or flying imposes limits on their size and efficiency. So they only fit niche uses in nomadic settings, like a temporary research camp. But then it's probably cheaper and more reliable to just use a fuel-powered generator. Also they're a bit of a hazard to aircraft (and each other if not steerable), are more at risk to storms, and the floating ones require expensive or explosive lifting gas. Too bad, because I think they're beautiful!
- LinAGKar 5y ago
  Yes, floating ones won't rise higher than to the surface.
mrfusion 5y ago
> taller they get, the harder they will be to repair If they’re floating couldn’t we have a mechanism to sink them to a reasonable height during repairs? Or it wouldn’t seem to be that hard to have ships with large ladders or a crane for repairs. (I couldn’t read the article because it’s completely paywalled.)
- flavius29663 5y ago
  Interesting idea. I think the problem is with getting salty water everywhere. Salt is the main killer out on the ocean. Also, it you lower it enough you will end up with the blades in the water, I really don't think you want that during wavey weather. Anyway, this extra height would solve a non-problem. It makes little difference if a human has to climb 100 or 300 meters. It's still work at heights - same kind of protocols and gear. If it's something that the humans can't fix (replace the gearbox or something massive) - then you need a crane anyway. Maybe the only issue would be with the waves moving the turbines enough to make the humans seasick at that height. Not sure, I can't see the whole article.
  - throwaway0a5e 5y ago
    It's basically a fiberglass tube. Corrosion from a quick dunk is a trivially solve-able issue since everything that could corrode will already need to be protected enough fora decades long service life in salt spray. I can't see sinking it for routine maintenance being cost effective. Even at a hundreds of dollars per man hour it's still probably not gonna be cheaper than making the maintenance people climb a ladder. That said, being able to lay over the main tube at like 60deg would make it way easier to construct them since you could use a much smaller and cheaper crane to assemble and it would minimize the side to side movement caused by rolling. You basically just need a cleverly engineered chamber to pull that off since the ship can have all the pumping hardware.
    - flavius29663 5y ago
      > lay over the main tube In my opinion, the main tubes are nowhere near strong enough to support the weight that way! They are weaker than they appear. The companies can built them so high because they gave up the idea that the tower can withstand any wind thrown at it and still oppose the wind enough to produce energy. Instead, smart computer programs turn the propeller angles independently, so that when the blade reaches the top (where it exerts maximum torque trying to topple the tower), it is angled such that it won't catch too much wind. Then when the blade is near the bottom, it's turned again in order to capture most wind.
spenrose 5y ago
https://twitter.com/ramez/status/1418261837255118849 https://twitter.com/ramez/status/1418261837255118849 "1. No need for ocean bed fixation hardware. 2. Ultimately lower tons of steel & cement per MW (not true now, but coming). 3. Much lower EPC costs. Build in port, tow to destination. (No jack-up ships.) 3. Lower O&M (tow back to port) 4. Better wind resource, meaning higher AEP per year (amortizing capex over more MWH). 5. Better wind resource also means higher capacity factor -> increased value, slower value deflation.
- deleted 5y ago
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yreg 5y ago
This is about wind turbines floating in the ocean[0] There are also ideas for wind turbines floating in the air[1] [0] no paywall : https://www.bloomberg.com/news/articles/2021-07-15/shell-joins-with-iberdrola-in-bid-to-build-floating-wind-farms https://www.bloomberg.com/news/articles/2021-07-15/shell-joi... [1] : https://en.wikipedia.org/wiki/Airborne_wind_turbine https://en.wikipedia.org/wiki/Airborne_wind_turbine
teh_klev 5y ago
Sans paywall: https://archive.is/T5tic https://archive.is/T5tic
WaitWaitWha 5y ago
Can someone explain if they are not anchored to something, are they self positioning? i.e. have some propulsion to put themselves back where they were placed initially? Otherwise, these will be floating nightmares for shipping and sailing.
- londons_explore 5y ago
  They appear to still be anchored, but just with a rope rather than solid steel.
- de_Selby 5y ago
  I would imagine they are anchored to the seabed the same way floating oil rigs are.
- EMM_386 5y ago
  The article explains all of this, and a lot more. It's absolutely worth the read if you are interested in this stuff. This diagram shows some of the proposed anchoring systems. https://www.economist.com/img/b/1000/679/90/sites/default/files/20210724_STC112.png https://www.economist.com/img/b/1000/679/90/sites/default/fi...
- Gravityloss 5y ago
  You need the power cable anyway. So it must be anchored.
perihelions 5y ago
>"Principle’s uses a buoyant steel triangle that has water-filled cans at two of the vertices. These ballast tanks balance the weight of a turbine at the third vertex, with water pumped around inside the triangle to trim its stability." Do they mean trimmed in real time, like active control?
- epistasis 5y ago
  It's been a while since I watched this NREL talk, but my fuzzy recollection is that there is some amount of active control: https://youtu.be/SavaSnOOrvw https://youtu.be/SavaSnOOrvw
- WJW 5y ago
  Yes, since the turbine creates different force vectors for different wind directions/speeds and the power generated is greatest when the mast is fully vertical, they actively re-trim when the wind direction and speed changes.
Confiks 5y ago
Reminds me of the incredible engineering done by Makani, as told in this 2 hours long autodocumentary [1]. They shut down in 2020 because they didn't see a path towards commercializing their airborne wind turbine. They made a non-assertion pledge on their patents, and open sourced much of their code (simulations, firmware) [2]. [1] https://www.youtube.com/watch?v=qd_hEja6bzE https://www.youtube.com/watch?v=qd_hEja6bzE [2] https://github.com/google/makani https://github.com/google/makani
- latchkey 5y ago
  You just beat me to this! I deleted my comment. I can't agree more. If you are at all curious about this topic, the documentary is well worth the viewing!
- elliottkember 5y ago
  A whole bunch of their equipment started showing up on auction sites recently - including a few fire engines. I was extremely tempted to pick up a $3,000 fire engine.
  - deleted 5y ago
    [deleted]
  - eloff 5y ago
    Those sell for a quarter million used, I think that's worth it barring major mechanical issues.
    - elliottkember 5y ago
      Yes, that's what I thought too. The only wrinkle was the logistical problem of where to park it.
- krisoft 5y ago
  Spoilers follow! I usually don't cry at movies. I cried when Mufasa died in the Lion King, and I nearly cried when the last prototype of Makani crashed into the sea in the linked documentary. So much good engineering, and effort, and hopes and dreams and sweat went into the whole project. I really felt for the team there.
deleted 5y ago
[deleted]
Bhilai 5y ago
Off topic: I see a lot of interesting Economist articles posted on HN. Is it worth subscribing to? Current offers show $94.50 for first year and then $189 from second year for digital access.
- pomian 5y ago
  Their audio versions are very well done. The reading is clear and non monotonous. You can play back faster obviously. They are a very good magazine. They have their stance, but it is consistent. For knowledge of what's going on in the whole world, it's very good. I recommend it. Those prices sound high though.
- crazygringo 5y ago
  If you're interested in international news, politics, and economics with extensive analysis, then there's no better source. If you're interested mainly in domestic news, mainly tech/science/culture, or "just the facts" without analysis, then probably not.
  - CyanBird 5y ago
    Heavily disagree Le Monde Diplomatique or Voltaire Network are just infinitely better for acquiring a better macro perspective of the world, if anything Economist is just renowned for bounding the scope of debate
    - crazygringo 5y ago
      Wow, "infinitely" better? That's quite a strong opinion. But I'm curious how you think they give a "better macro perspective"? Is it in the range of stories covered, and so what kind of stuff do they cover that the Economist doesn't? Or is it the "debate", and I'm curious what positions you don't find in the Economist? Especially since their articles are very often in dialectical format, presenting competing interpretations of events as seen from the different sides involved in an issue. I mean it's true they're not going to apply a European democratic socialism lens to American political issues... but then they're looking at European issues through a European lens.
_joel 5y ago
Would this reduce the environmental impact? Particularly noise pollution during the pile driving for traditional turbines, that affects whales and such.
philipkglass 5y ago
California's renewables mix is currently solar-heavy. Water depth increases steeply off its coast so traditional fixed bottom offshore turbines don't have many viable locations. Floating wind would be a great complement to solar there if the technology matures.
- eloff 5y ago
  Much of the West Coast is in the same boat.
- _rpd 5y ago
  It's interesting tech, but a big part of offshore wind power is bringing the power back to shore. Onshore wind and solar are going to have the advantage there for the foreseeable future.
- okareaman 5y ago
  I live on the Central Coast and it never struck me as very windy around here, at least compared to other places I've been. I looked it up and as I thought, the winds are further North: 2020 Offshore Wind Resource Assessment for the California Pacific Outer Continental Shelf https://www.nrel.gov/docs/fy21osti/77642.pdf https://www.nrel.gov/docs/fy21osti/77642.pdf
  - nradov 5y ago
    It gets plenty windy just a few miles out into the Pacific Ocean. Pay attention to the marine forecast for a few months and notice how often they include small craft advisories.
  - hadlock 5y ago
    Most of the wind is 4-12 miles offshore, as the wind rolls down the coast it's blocked by the mountains that run along the coast. At 25 miless offshore you get into mesoscale wind patterns which are extremely stable and aren't impacted nearly as much by day/night cycle, and can be forecasted with great reliability days and sometimes weeks in advance, particularly in the summer once the north pacific high settles in between CA and HI.
xwdv 5y ago
What toll are all these wind farms going to take on global weather patterns if they continue to multiply?
- deleted 5y ago
  [deleted]
- eloff 5y ago
  Basically rounded down to none. While we continually underestimate our unintended impacts, I don't believe that's the case here. Even if we sourced 100% of the world's energy needs from wind it would be slowing a miniscule fraction of the total atmospheric movements. Think of the three dimensional space occupied by turbines versus the vast volume of air with no turbines.
- jandrese 5y ago
  I'm thinking they may have a double impact on combating global warming. Not only do they displace fossil fuel emissions, but they pull excess energy out of the atmosphere. However, the scale they operate at is a rounding error on a global scale.
xyzzy21 5y ago
Yeah but... if the barge base the tower is attached to isn't of the order as large on each side as the tower is tall, the first gale will capsize it.
- jnwatson 5y ago
  It could also use an adjustable centerboard like some sailboats.
  - nradov 5y ago
    Centerboards are really only effective when the boat is moving. For static stability you need a keel with enough ballast to provide a sufficient righting moment.
- dasv 5y ago
  Don't forget that although the base floats it is also tethered to the seafloor with chains and anchors! The mooring provides most of the stability, and if it were not tethered then it would not stay in place at all.
kumarvvr 5y ago
Those wind turbines are upwards of 10 MW each. That is massive. People dont get the scale of it. If the dynamics, control amd reliability are proven, then the only hurdle would be drawing high power carrying cables through corrosive sea waters. And, build cables that withstand constant movement and bending. Edit - Wind turbine capacity.
- gameswithgo 5y ago
  I believe most of the huge ones you see on the interstate are ~2MW, so imagine ~5x the scale woooo
  - jhayward 5y ago
    > imagine ~5x the scale For wind turbines power is proportional to the swept area, and to the square of the diameter. Doubling the diameter quadruples the available power. So for the same wind speed the difference between a 3MW (commonly installed today) land-based turbine and a 15MW turbine (largest offshore class today) would be a little over twice the diameter. Of course, the offshore monsters are also taller to allow greater swept area, and to take advantage of better resource at height.
- danans 5y ago
  > Those wind turbines are upwards of 10 MW each Assuming a 35% capacity factor (taken from land-based wind turbines, offshore should be higher), that's 84MWh/day. The average California single family home uses 20 kWh per day, which means that that capacity factor this turbine could power about 4200 homes per day. For comparison, a 10 megawatt solar project, assuming a standard 20% solar panel efficiency and one kilowatt per square meter insolation, would require a five square kilometer solar array. The capacity factor of PV solar is inherently limited by sunlight hours, but it is around 28% in California. If offshore wind is available 24 hours at such a huge scale, it could change the renewable energy mix considerably. In that world the biggest advantage of solar would be lower maintenance costs and greater visibility at smaller scale (for example, coupled with batteries to form micro grids).
  - 5y ago
ncmncm 5y ago
This is actually an easy problem. (Anyway, easy given the size of the things.) Make a ship that can nest the top of the tower close to horizontally, axis up. Winch the top of the tower down into its nest. Fix the turbine using cranes attached to the ship. When finished, unwind the winch, and let the tower right itself. There will be complications. You might need to release (one or more of) the tower's mooring lines after it has tilted some ways, and re-attach them on its way back up. You will need a cable attached to the top of the tower to winch it down with, either left there from construction or attached at need. The ship probably needs a boom sticking out aft to the base of the tower, with a grabber that can swivel up as the tower comes down. The nest and boom need to be customized for the tower design operated on, but the ship can get those mounted before it goes out. The nacelle probably has to be re-designed from scratch to be worked on from that angle.
- ChuckMcM 5y ago
  For some definition of easy :-). Consider the following, in order to work, the turbine (which has a fairly high mass) has to avoid being blown out of position by the very winds it is trying to harness. Because it is quite high, the distance between the turbine and the base form a moment arm of great length. So the entire system understands the torque moment on the turbine and has in place the ability to avoid tilting. Compare that with the displacement mass of pretty much any ship you might send out there to work on it. I'm guessing that you're more than likely to winch the maintenance ship out of the water than your are going to get that turbine to tilt over. (disclaimer here, a spent a lot of my youth sailing and got a pretty good appreciation both for how "hard" ocean winds could try to tip you and how much a boat with a serious keel could resist that attempt to turn them over.)
  - ncmncm 5y ago
    You might also need to attach a float at the bottom of the tower, and inflate it while winching down. As I said, there will be complications. But that's what engineers are for. Anyway, ships are often astonishingly massive.
    - 5y ago
swman 5y ago
BIT OFF TOPIC sorry, but - What about the crazy rain fall that's happening right now? Could some sort of devices be placed into subway tunnels and storm drains that pushes a turbine to generate power? Sorry if that sounds dumb, I'm just curious.
- teruakohatu 5y ago
  Not really. Micro-hydro is a thing (YouTube is your friend here) but there is surprisingly little energy to be harvested from small rivers with only moderate drops. Great for a someone living off the grid who wants to generate power overnight, but not worth it otherwise.
- amelius 5y ago
  I guess turbines will slow down the water, leading to more floods.
  - pbhjpbhj 5y ago
    Wouldn't it increase basin lag and so reduce flooding?
- ZeroGravitas 5y ago
  Some pipelines have passive devices to slow the content of pipes e.g. if your city water supply is coming from a higher region. A recent trend is placing turbines that generate electricity rather than heat from this process. A double win if the heat was unwanted and lead to energy being used for cooling.

135 points by prostoalex 5y ago

I wonder if balloon wind turbines might not be a better approach in those circumstances. You have to accept smaller blades but I'd think the other advantages would be worth it.

flavius29663 5y ago
Wind turbines output grows with the size of the blade (it's squared). http://large.stanford.edu/courses/2011/ph240/parise1/ http://large.stanford.edu/courses/2011/ph240/parise1/ edit: When you take into account that the blade size increase means a higher tower (and thus higher wind speeds), the increase is more staggering, because wind speed is cubed in the final output: > Combining the effects of height and blade length, doubling the height and doubling the blade length will result in an increase of power over 22 fold. This is why companies try so hard to build bigger blades, higher. Current blades are just massive https://cdn.vox-cdn.com/uploads/chorus_asset/file/10382023/Wind_turbine_heights.jpg https://cdn.vox-cdn.com/uploads/chorus_asset/file/10382023/W... The wingspan of a 747 is 68 meters. The newest GE turbine has a diameter of 220 meters, each blade is 107 meters. One blade is 50% longer than the whole wingspan of 747. You can fit 3x747 planes inside the area swept by a current turbine. This is why Google's Makani project never took off...I really hoped for that project to succeed, it was very cool, but there is no way to compete with the bladed giants. edited to address cjbest and baq valid comments
- cjbest 5y ago
  I think you meant it grows as the square of the blade length (and the cube of the wind speed) From your link: > Thus, the power passing through the blades of the turbine, and thus in turn the power of the electricity the turbine generates, is proportional to the square of the length of the blades: a doubling of blade length leads to a quadrupling of wind power passing over the blades. Doesn’t change your conclusion of course. Thanks for the interesting link!
  - flavius29663 5y ago
    you're right, and I roughly knew that, I just didn't knew how to express it well enough in a short manner. When you increase the blade you also have access to higher winds, so the total output is much much bigger. I was focusing on the quote below and I didn't knew how to express it better. > Combining the effects of height and blade length, doubling the height and doubling the blade length will result in an increase of power over 22 fold.
- baq 5y ago
  > grows exponentially with the size of the blade (it's cubed). sorry, couldn't resist nitpicking. you're contradicting yourself here :)
  - adrianmonk 5y ago
    If only it were exponential... build one REALLY big blade and power the whole earth.
- kitd 5y ago
  The newest GE turbine has a radius of 220 meters, each blade is 107 meters. My last maths class was decades ago, but ... 'diameter'?
  - flavius29663 5y ago
    ha, I think I need more coffee this morning. Or maybe i was just too excited to type that out, finally something I know a little bit about on HN
mLuby 5y ago
I did a research project on this. Aerial wind turbines have two key advantages over terrestrial ones: access to steady high-speed winds at altitude, and limited ground footprint. But floating or flying imposes limits on their size and efficiency. So they only fit niche uses in nomadic settings, like a temporary research camp. But then it's probably cheaper and more reliable to just use a fuel-powered generator. Also they're a bit of a hazard to aircraft (and each other if not steerable), are more at risk to storms, and the floating ones require expensive or explosive lifting gas. Too bad, because I think they're beautiful!
LinAGKar 5y ago
Yes, floating ones won't rise higher than to the surface.

mrfusion 5y ago

> taller they get, the harder they will be to repair If they’re floating couldn’t we have a mechanism to sink them to a reasonable height during repairs? Or it wouldn’t seem to be that hard to have ships with large ladders or a crane for repairs. (I couldn’t read the article because it’s completely paywalled.)

flavius29663 5y ago
Interesting idea. I think the problem is with getting salty water everywhere. Salt is the main killer out on the ocean. Also, it you lower it enough you will end up with the blades in the water, I really don't think you want that during wavey weather. Anyway, this extra height would solve a non-problem. It makes little difference if a human has to climb 100 or 300 meters. It's still work at heights - same kind of protocols and gear. If it's something that the humans can't fix (replace the gearbox or something massive) - then you need a crane anyway. Maybe the only issue would be with the waves moving the turbines enough to make the humans seasick at that height. Not sure, I can't see the whole article.
- throwaway0a5e 5y ago
  It's basically a fiberglass tube. Corrosion from a quick dunk is a trivially solve-able issue since everything that could corrode will already need to be protected enough fora decades long service life in salt spray. I can't see sinking it for routine maintenance being cost effective. Even at a hundreds of dollars per man hour it's still probably not gonna be cheaper than making the maintenance people climb a ladder. That said, being able to lay over the main tube at like 60deg would make it way easier to construct them since you could use a much smaller and cheaper crane to assemble and it would minimize the side to side movement caused by rolling. You basically just need a cleverly engineered chamber to pull that off since the ship can have all the pumping hardware.
  - flavius29663 5y ago
    > lay over the main tube In my opinion, the main tubes are nowhere near strong enough to support the weight that way! They are weaker than they appear. The companies can built them so high because they gave up the idea that the tower can withstand any wind thrown at it and still oppose the wind enough to produce energy. Instead, smart computer programs turn the propeller angles independently, so that when the blade reaches the top (where it exerts maximum torque trying to topple the tower), it is angled such that it won't catch too much wind. Then when the blade is near the bottom, it's turned again in order to capture most wind.

spenrose 5y ago

https://twitter.com/ramez/status/1418261837255118849 https://twitter.com/ramez/status/1418261837255118849 "1. No need for ocean bed fixation hardware. 2. Ultimately lower tons of steel & cement per MW (not true now, but coming). 3. Much lower EPC costs. Build in port, tow to destination. (No jack-up ships.) 3. Lower O&M (tow back to port) 4. Better wind resource, meaning higher AEP per year (amortizing capex over more MWH). 5. Better wind resource also means higher capacity factor -> increased value, slower value deflation.

deleted 5y ago
[deleted]

yreg 5y ago

This is about wind turbines floating in the ocean[0] There are also ideas for wind turbines floating in the air[1] [0] no paywall : https://www.bloomberg.com/news/articles/2021-07-15/shell-joins-with-iberdrola-in-bid-to-build-floating-wind-farms https://www.bloomberg.com/news/articles/2021-07-15/shell-joi... [1] : https://en.wikipedia.org/wiki/Airborne_wind_turbine https://en.wikipedia.org/wiki/Airborne_wind_turbine

teh_klev 5y ago

Sans paywall: https://archive.is/T5tic https://archive.is/T5tic

WaitWaitWha 5y ago

Can someone explain if they are not anchored to something, are they self positioning? i.e. have some propulsion to put themselves back where they were placed initially? Otherwise, these will be floating nightmares for shipping and sailing.

londons_explore 5y ago
They appear to still be anchored, but just with a rope rather than solid steel.
de_Selby 5y ago
I would imagine they are anchored to the seabed the same way floating oil rigs are.
EMM_386 5y ago
The article explains all of this, and a lot more. It's absolutely worth the read if you are interested in this stuff. This diagram shows some of the proposed anchoring systems. https://www.economist.com/img/b/1000/679/90/sites/default/files/20210724_STC112.png https://www.economist.com/img/b/1000/679/90/sites/default/fi...
Gravityloss 5y ago
You need the power cable anyway. So it must be anchored.

perihelions 5y ago

>"Principle’s uses a buoyant steel triangle that has water-filled cans at two of the vertices. These ballast tanks balance the weight of a turbine at the third vertex, with water pumped around inside the triangle to trim its stability." Do they mean trimmed in real time, like active control?

epistasis 5y ago
It's been a while since I watched this NREL talk, but my fuzzy recollection is that there is some amount of active control: https://youtu.be/SavaSnOOrvw https://youtu.be/SavaSnOOrvw
WJW 5y ago
Yes, since the turbine creates different force vectors for different wind directions/speeds and the power generated is greatest when the mast is fully vertical, they actively re-trim when the wind direction and speed changes.

Confiks 5y ago

Reminds me of the incredible engineering done by Makani, as told in this 2 hours long autodocumentary [1]. They shut down in 2020 because they didn't see a path towards commercializing their airborne wind turbine. They made a non-assertion pledge on their patents, and open sourced much of their code (simulations, firmware) [2]. [1] https://www.youtube.com/watch?v=qd_hEja6bzE https://www.youtube.com/watch?v=qd_hEja6bzE [2] https://github.com/google/makani https://github.com/google/makani

latchkey 5y ago
You just beat me to this! I deleted my comment. I can't agree more. If you are at all curious about this topic, the documentary is well worth the viewing!
elliottkember 5y ago
A whole bunch of their equipment started showing up on auction sites recently - including a few fire engines. I was extremely tempted to pick up a $3,000 fire engine.
- deleted 5y ago
  [deleted]
- eloff 5y ago
  Those sell for a quarter million used, I think that's worth it barring major mechanical issues.
  - elliottkember 5y ago
    Yes, that's what I thought too. The only wrinkle was the logistical problem of where to park it.
krisoft 5y ago
Spoilers follow! I usually don't cry at movies. I cried when Mufasa died in the Lion King, and I nearly cried when the last prototype of Makani crashed into the sea in the linked documentary. So much good engineering, and effort, and hopes and dreams and sweat went into the whole project. I really felt for the team there.

deleted 5y ago

[deleted]

Bhilai 5y ago

Off topic: I see a lot of interesting Economist articles posted on HN. Is it worth subscribing to? Current offers show $94.50 for first year and then $189 from second year for digital access.

pomian 5y ago
Their audio versions are very well done. The reading is clear and non monotonous. You can play back faster obviously. They are a very good magazine. They have their stance, but it is consistent. For knowledge of what's going on in the whole world, it's very good. I recommend it. Those prices sound high though.
crazygringo 5y ago
If you're interested in international news, politics, and economics with extensive analysis, then there's no better source. If you're interested mainly in domestic news, mainly tech/science/culture, or "just the facts" without analysis, then probably not.
- CyanBird 5y ago
  Heavily disagree Le Monde Diplomatique or Voltaire Network are just infinitely better for acquiring a better macro perspective of the world, if anything Economist is just renowned for bounding the scope of debate
  - crazygringo 5y ago
    Wow, "infinitely" better? That's quite a strong opinion. But I'm curious how you think they give a "better macro perspective"? Is it in the range of stories covered, and so what kind of stuff do they cover that the Economist doesn't? Or is it the "debate", and I'm curious what positions you don't find in the Economist? Especially since their articles are very often in dialectical format, presenting competing interpretations of events as seen from the different sides involved in an issue. I mean it's true they're not going to apply a European democratic socialism lens to American political issues... but then they're looking at European issues through a European lens.

_joel 5y ago

Would this reduce the environmental impact? Particularly noise pollution during the pile driving for traditional turbines, that affects whales and such.

philipkglass 5y ago

California's renewables mix is currently solar-heavy. Water depth increases steeply off its coast so traditional fixed bottom offshore turbines don't have many viable locations. Floating wind would be a great complement to solar there if the technology matures.

eloff 5y ago
Much of the West Coast is in the same boat.
_rpd 5y ago
It's interesting tech, but a big part of offshore wind power is bringing the power back to shore. Onshore wind and solar are going to have the advantage there for the foreseeable future.
okareaman 5y ago
I live on the Central Coast and it never struck me as very windy around here, at least compared to other places I've been. I looked it up and as I thought, the winds are further North: 2020 Offshore Wind Resource Assessment for the California Pacific Outer Continental Shelf https://www.nrel.gov/docs/fy21osti/77642.pdf https://www.nrel.gov/docs/fy21osti/77642.pdf
- nradov 5y ago
  It gets plenty windy just a few miles out into the Pacific Ocean. Pay attention to the marine forecast for a few months and notice how often they include small craft advisories.
- hadlock 5y ago
  Most of the wind is 4-12 miles offshore, as the wind rolls down the coast it's blocked by the mountains that run along the coast. At 25 miless offshore you get into mesoscale wind patterns which are extremely stable and aren't impacted nearly as much by day/night cycle, and can be forecasted with great reliability days and sometimes weeks in advance, particularly in the summer once the north pacific high settles in between CA and HI.

xwdv 5y ago

What toll are all these wind farms going to take on global weather patterns if they continue to multiply?

deleted 5y ago
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eloff 5y ago
Basically rounded down to none. While we continually underestimate our unintended impacts, I don't believe that's the case here. Even if we sourced 100% of the world's energy needs from wind it would be slowing a miniscule fraction of the total atmospheric movements. Think of the three dimensional space occupied by turbines versus the vast volume of air with no turbines.
jandrese 5y ago
I'm thinking they may have a double impact on combating global warming. Not only do they displace fossil fuel emissions, but they pull excess energy out of the atmosphere. However, the scale they operate at is a rounding error on a global scale.

xyzzy21 5y ago

Yeah but... if the barge base the tower is attached to isn't of the order as large on each side as the tower is tall, the first gale will capsize it.

jnwatson 5y ago
It could also use an adjustable centerboard like some sailboats.
- nradov 5y ago
  Centerboards are really only effective when the boat is moving. For static stability you need a keel with enough ballast to provide a sufficient righting moment.
dasv 5y ago
Don't forget that although the base floats it is also tethered to the seafloor with chains and anchors! The mooring provides most of the stability, and if it were not tethered then it would not stay in place at all.

kumarvvr 5y ago

Those wind turbines are upwards of 10 MW each. That is massive. People dont get the scale of it. If the dynamics, control amd reliability are proven, then the only hurdle would be drawing high power carrying cables through corrosive sea waters. And, build cables that withstand constant movement and bending. Edit - Wind turbine capacity.

gameswithgo 5y ago
I believe most of the huge ones you see on the interstate are ~2MW, so imagine ~5x the scale woooo
- jhayward 5y ago
  > imagine ~5x the scale For wind turbines power is proportional to the swept area, and to the square of the diameter. Doubling the diameter quadruples the available power. So for the same wind speed the difference between a 3MW (commonly installed today) land-based turbine and a 15MW turbine (largest offshore class today) would be a little over twice the diameter. Of course, the offshore monsters are also taller to allow greater swept area, and to take advantage of better resource at height.
danans 5y ago
> Those wind turbines are upwards of 10 MW each Assuming a 35% capacity factor (taken from land-based wind turbines, offshore should be higher), that's 84MWh/day. The average California single family home uses 20 kWh per day, which means that that capacity factor this turbine could power about 4200 homes per day. For comparison, a 10 megawatt solar project, assuming a standard 20% solar panel efficiency and one kilowatt per square meter insolation, would require a five square kilometer solar array. The capacity factor of PV solar is inherently limited by sunlight hours, but it is around 28% in California. If offshore wind is available 24 hours at such a huge scale, it could change the renewable energy mix considerably. In that world the biggest advantage of solar would be lower maintenance costs and greater visibility at smaller scale (for example, coupled with batteries to form micro grids).
- 5y ago

ncmncm 5y ago

This is actually an easy problem. (Anyway, easy given the size of the things.) Make a ship that can nest the top of the tower close to horizontally, axis up. Winch the top of the tower down into its nest. Fix the turbine using cranes attached to the ship. When finished, unwind the winch, and let the tower right itself. There will be complications. You might need to release (one or more of) the tower's mooring lines after it has tilted some ways, and re-attach them on its way back up. You will need a cable attached to the top of the tower to winch it down with, either left there from construction or attached at need. The ship probably needs a boom sticking out aft to the base of the tower, with a grabber that can swivel up as the tower comes down. The nest and boom need to be customized for the tower design operated on, but the ship can get those mounted before it goes out. The nacelle probably has to be re-designed from scratch to be worked on from that angle.

ChuckMcM 5y ago
For some definition of easy :-). Consider the following, in order to work, the turbine (which has a fairly high mass) has to avoid being blown out of position by the very winds it is trying to harness. Because it is quite high, the distance between the turbine and the base form a moment arm of great length. So the entire system understands the torque moment on the turbine and has in place the ability to avoid tilting. Compare that with the displacement mass of pretty much any ship you might send out there to work on it. I'm guessing that you're more than likely to winch the maintenance ship out of the water than your are going to get that turbine to tilt over. (disclaimer here, a spent a lot of my youth sailing and got a pretty good appreciation both for how "hard" ocean winds could try to tip you and how much a boat with a serious keel could resist that attempt to turn them over.)
- ncmncm 5y ago
  You might also need to attach a float at the bottom of the tower, and inflate it while winching down. As I said, there will be complications. But that's what engineers are for. Anyway, ships are often astonishingly massive.
  - 5y ago

swman 5y ago

BIT OFF TOPIC sorry, but - What about the crazy rain fall that's happening right now? Could some sort of devices be placed into subway tunnels and storm drains that pushes a turbine to generate power? Sorry if that sounds dumb, I'm just curious.

teruakohatu 5y ago
Not really. Micro-hydro is a thing (YouTube is your friend here) but there is surprisingly little energy to be harvested from small rivers with only moderate drops. Great for a someone living off the grid who wants to generate power overnight, but not worth it otherwise.
amelius 5y ago
I guess turbines will slow down the water, leading to more floods.
- pbhjpbhj 5y ago
  Wouldn't it increase basin lag and so reduce flooding?
ZeroGravitas 5y ago
Some pipelines have passive devices to slow the content of pipes e.g. if your city water supply is coming from a higher region. A recent trend is placing turbines that generate electricity rather than heat from this process. A double win if the heat was unwanted and lead to energy being used for cooling.