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I have repelled (using Industrial Rope Access) off hundreds of multi-megawatt Wind Turbines on $1B+ wind farms around the world to inspect and repair the 13+ to

I have repelled (using Industrial Rope Access) off hundreds of multi-megawatt Wind Turbines on $1B+ wind farms around the world to inspect and repair the 13+ ton fiberglass blades and wanted to give my 2 cents. [A clarification: Wind Turbines generate electricity, Wind Mills mill flour. It's a small but important detail.] Operation & Maintenance expense is my biggest issue with new technology. I have met many design engineers that have never been inside of a nacelle or even visited a wind farm. In the real world generators and blades break, hurricanes, lightning, shit happens. Cranes are extremely expensive and a 2MW "mast" that can compete with today's technology is going to be crazy tall. How to repair a lightning cable? Cranes are over $10k per day and cables take a few days to fix. Today there is a 26 story ladder in the interior of the support tower that people climb up to fix hardware in the nacelle. To inspect the blades we then rig our anchors to the generator, pop out the top hatch and repel over the nose cone and down onto a blade in the "down" position. The only specialized hardware needed is anchors, carabiners, ropes, harness and helmet. Vortex Bladeless would be impossible to inspect and repair using this method, yes drones are great for inspection, but what about repairing a stress crack on the tip? You would need a crazy tall crane that is even more expensive and with cranes the wind speeds need to be a fraction that of Industrial Rope Access. This means your available repair days are even less and the turbine has to be shut down for longer for the fix to occur. I am all for new technology and crowd financing, but there are many practical obstacles this team needs to overcome in the design phase to build a product that can actually scale in the real world. Also, feel free to AMA if you have specific wind turbine questions.

sliverstorm 11y ago
I try not to be pedantic, but I was really confused for a minute- I believe you mean "rappel". (Or if you want to sound fancy, "abseil")
- startupfounder 11y ago
  You are correct! My right hand pinky finger doesn't have the dexterity it used to. I can crank out words with one "P" in them, but when I have to do the double tap of the "P" it becomes a real issue.
  - sliverstorm 11y ago
    I actually slip up and omit a "p" from time to time, but it's really the "e" - "rapel" vs "repel" - that threw me :)
    - startupfounder 11y ago
      And I suck at spelling :)
barryfandango 11y ago
It would be really cool if the mast could retract, either using some kind of collapsing structure or a hole dug out underneath the structure. Great for repairs, also would allow a farm to retract for extreme weather events.
- boombip 11y ago
  Yeah, until the retraction mechanism breaks.
  - wlesieutre 11y ago
    No problem, just put the retraction mechanism in a lifting mechanism to lift it out of the ground for maintenance!
kbenson 11y ago
> a 2MW "mast" that can compete with today's technology is going to be crazy tall I wonder about how the power generated scales as the size increases. It's 100W at 9', and 4kW at 40'. At ~4.5x the height there's 40x the power generated. It's foolish to assume the same exponential gains apply continuously, but given the reduced footprint, is it possible that laying out five of the 40' units is sufficient for 2MW (edit: wait, I totally fudged that math, so this point doesn't really make sense), and at that size, you might be able to just use a bucket truck for maintenance? We shouldn't assume just because it's a new technology that the same problems don't need to be addressed, but we also shouldn't assume the same problems need to be addressed in the same manner. This article doesn't do a lot to explain the details, and as you've explained I've heard that maintenance of wind turbines is where a lot of the money to run wind farms goes, so it's interesting to look at new designs from the standpoint of how it may radically change maintenance, not just scale with the current methods. That said, you obviously have more experience with this than me, so hopefully you'll be able to provide some more perspective on the ideas here. P.S. Something that occurs to me is that I have no idea how they stop the oscillation caused by the wind for maintenance on those. You can lock the turbine blades, but I'm not sure how you prevent something made to oscillate naturally in the wind from doing so, easily. P.P.S I totally messed up my math because I wasn't thinking straight, 5x4kW is not even close to 2MW. I'll leave this here for historical purpose, but much of my point lacks any weight now...
- startupfounder 11y ago
  > I wonder about how the power generated scales as the size increases. Yes, there are two factors, wind speed and blade swept area. Height: "Energy in the wind is not linear. Double the wind speed and the energy increases not by double but by a factor of 8. As speed increases the power is increased by a cube factor."[0] You want to capture that higher elevation wind to maximize power output while also factoring in the cost of the tower heigh and stability. Most 2MW turbines have a tower height of between 60 and 100 meters depending on the local wind profile. Blade Swept Area: "Energy captured by the rotor is linear. If you double the swept area, you double the amount of energy it can capture."[0] If you can double the length of a classic wind turbine the swept area increases by a factor of 4! This is where the problem lies. Even if there was the cost efficient method of building a 2MW Mast turbine the swept area would only be a fraction that of a classic wind turbine, say only 45 degrees in each direction. This makes the height necessary just unrealistic. Just thinking about an entire farm of these these wobbling back and forth makes me giggle. > we also shouldn't assume the same problems need to be addressed in the same manner. Totally agreed! But these fiberglass "Masts" are still in the outdoor environment. They still get struck by lightning, they still need generators replaced, they still have electronics, etc. This is why I have moved away from my believe system that wind energy will make up a huge factor of our energy production needs and have become very bullish on solar. Mechanical electricity generation requires maintenance and moving parts increase complexity exponentially. Wind energy is no longer a technical problem to be solved, we have already done that with three bladed turbines, it's a financial and incremental improvement problem. [0] http://www.power-talk.net/swept-area.html http://www.power-talk.net/swept-area.html
ChuckMcM 11y ago
It is certainly a valid point that maintenance costs are a huge burden on wind farms, that said, you cannot really jump to the conclusion that 2MW of generation capability would be deployed as one giant tower. From the web site it seems it would be 2x 1MW towers but it could easily be 10 separate 200kW towers or even 100 20kW towers. The density of a this with respect to wind turbines seems a bit higher.[1] That said, their web site makes them out to be idealistic dreamers (I know that sounds judgemental but it is the impression I got from it). If Google were still running the RE<C initiative I'd suggest they put a couple of test units next to the data center at The Dalles (its on the Columbia River and was always windy whenever I visited there). If they can build a 4 - 10kW one and its something you can stick in your backyard, I would expect that they can build a small business out of that to develop the expertise to build the big ones. I worry that if they try to do too much too soon they will become overwhelmed. [1] Caveat the amount of energy you can pull out of a moving mass of air at STP is finite.
- startupfounder 11y ago
  Most wind farms are on leased land and the fee is based on the MWh generated. Farmers want to maximize revenue from wind harvesting while minimizing crop harvest revenue loss. Remember roads are built between turbines for big cranes and trailers to deliver and install the turbines and there is parking underneath the turbine for maintenance workers. Having 500 4kw systems cuts into harvest revenues as do 10 20kw systems as the equivalent square footage lost to generate 1MWh is an order of magnitude larger. Also, wind turbines blades in colder climates tend to accumulate ice in the winter and thus are permitted to be located away from populated areas. Some big chunks of ice have been flung hundreds of meters. The larger the blade the further the distance you need to put your structure for safety reasons. These masts shouldn't be put on buildings (vibration) or near populations (ice).
  - kbenson 11y ago
    It sounds like you are attributing the same space usage for these types of generators as wind turbines, when it appears they could be much more closely packed. I wouldn't expect ten of these to use ten times the square footage as the wind turbines. Additionally, I wouldn't expect ice to be flung as far (but I'm not sure what the oscillation is really like), but from the design, maybe ice poses other challenges to these.
reneherse 11y ago
In this case, why bring the worker to the repair site when you can bring the repair site to the worker? This new technology is in the form of a cantilevered mast. It would be a basic engineering problem to design the structure to be raised and lowered when repair is needed. The primitive model is a tabernacled mast on a sailboat.[1] [1] http://imgur.com/XwMCxbv http://imgur.com/XwMCxbv
- startupfounder 11y ago
  > It would be a basic engineering problem to design the structure to be raised and lowered when repair is needed. I'm a big sailer too. I used to crew on racing boats and classic schooners. Let's say we have a cantilevered mast and can swap it out "quickly". For 2MW worth of generation that would be a massive engineering feat and would mean that you have inventory not being utilized stored in the warehouse. Not just a generator or blade, but an entire system unutilized sitting around! Also most sailing masts are fairly light (aluminium) and short (30'). A 2MW wind mast would be 10x a sailing mast and hold all of the generator and electronics, not just a hollow tube that needs to be structurally sound. also masts are designed to be rigid and are held in place using shrouds and stays. A wind mast designed to move can not be held in place using guy-wires as that defeats the purpose of the dynamic wind mast. Workers on these wind farms are making between $10 and $25 each and every hour. Some specialized workers are making double that at times, but let's keep the average of $20/hr. It doesn't make economical sense even if you didn't need a crane to swap it out. And yes you would need a crane as this would be a multi-ton structure.

sliverstorm 11y ago

I try not to be pedantic, but I was really confused for a minute- I believe you mean "rappel". (Or if you want to sound fancy, "abseil")

startupfounder 11y ago
You are correct! My right hand pinky finger doesn't have the dexterity it used to. I can crank out words with one "P" in them, but when I have to do the double tap of the "P" it becomes a real issue.
- sliverstorm 11y ago
  I actually slip up and omit a "p" from time to time, but it's really the "e" - "rapel" vs "repel" - that threw me :)
  - startupfounder 11y ago
    And I suck at spelling :)

barryfandango 11y ago

It would be really cool if the mast could retract, either using some kind of collapsing structure or a hole dug out underneath the structure. Great for repairs, also would allow a farm to retract for extreme weather events.

boombip 11y ago
Yeah, until the retraction mechanism breaks.
- wlesieutre 11y ago
  No problem, just put the retraction mechanism in a lifting mechanism to lift it out of the ground for maintenance!

kbenson 11y ago

> a 2MW "mast" that can compete with today's technology is going to be crazy tall I wonder about how the power generated scales as the size increases. It's 100W at 9', and 4kW at 40'. At ~4.5x the height there's 40x the power generated. It's foolish to assume the same exponential gains apply continuously, but given the reduced footprint, is it possible that laying out five of the 40' units is sufficient for 2MW (edit: wait, I totally fudged that math, so this point doesn't really make sense), and at that size, you might be able to just use a bucket truck for maintenance? We shouldn't assume just because it's a new technology that the same problems don't need to be addressed, but we also shouldn't assume the same problems need to be addressed in the same manner. This article doesn't do a lot to explain the details, and as you've explained I've heard that maintenance of wind turbines is where a lot of the money to run wind farms goes, so it's interesting to look at new designs from the standpoint of how it may radically change maintenance, not just scale with the current methods. That said, you obviously have more experience with this than me, so hopefully you'll be able to provide some more perspective on the ideas here. P.S. Something that occurs to me is that I have no idea how they stop the oscillation caused by the wind for maintenance on those. You can lock the turbine blades, but I'm not sure how you prevent something made to oscillate naturally in the wind from doing so, easily. P.P.S I totally messed up my math because I wasn't thinking straight, 5x4kW is not even close to 2MW. I'll leave this here for historical purpose, but much of my point lacks any weight now...

startupfounder 11y ago
> I wonder about how the power generated scales as the size increases. Yes, there are two factors, wind speed and blade swept area. Height: "Energy in the wind is not linear. Double the wind speed and the energy increases not by double but by a factor of 8. As speed increases the power is increased by a cube factor."[0] You want to capture that higher elevation wind to maximize power output while also factoring in the cost of the tower heigh and stability. Most 2MW turbines have a tower height of between 60 and 100 meters depending on the local wind profile. Blade Swept Area: "Energy captured by the rotor is linear. If you double the swept area, you double the amount of energy it can capture."[0] If you can double the length of a classic wind turbine the swept area increases by a factor of 4! This is where the problem lies. Even if there was the cost efficient method of building a 2MW Mast turbine the swept area would only be a fraction that of a classic wind turbine, say only 45 degrees in each direction. This makes the height necessary just unrealistic. Just thinking about an entire farm of these these wobbling back and forth makes me giggle. > we also shouldn't assume the same problems need to be addressed in the same manner. Totally agreed! But these fiberglass "Masts" are still in the outdoor environment. They still get struck by lightning, they still need generators replaced, they still have electronics, etc. This is why I have moved away from my believe system that wind energy will make up a huge factor of our energy production needs and have become very bullish on solar. Mechanical electricity generation requires maintenance and moving parts increase complexity exponentially. Wind energy is no longer a technical problem to be solved, we have already done that with three bladed turbines, it's a financial and incremental improvement problem. [0] http://www.power-talk.net/swept-area.html http://www.power-talk.net/swept-area.html

ChuckMcM 11y ago

It is certainly a valid point that maintenance costs are a huge burden on wind farms, that said, you cannot really jump to the conclusion that 2MW of generation capability would be deployed as one giant tower. From the web site it seems it would be 2x 1MW towers but it could easily be 10 separate 200kW towers or even 100 20kW towers. The density of a this with respect to wind turbines seems a bit higher.[1] That said, their web site makes them out to be idealistic dreamers (I know that sounds judgemental but it is the impression I got from it). If Google were still running the RE<C initiative I'd suggest they put a couple of test units next to the data center at The Dalles (its on the Columbia River and was always windy whenever I visited there). If they can build a 4 - 10kW one and its something you can stick in your backyard, I would expect that they can build a small business out of that to develop the expertise to build the big ones. I worry that if they try to do too much too soon they will become overwhelmed. [1] Caveat the amount of energy you can pull out of a moving mass of air at STP is finite.

startupfounder 11y ago
Most wind farms are on leased land and the fee is based on the MWh generated. Farmers want to maximize revenue from wind harvesting while minimizing crop harvest revenue loss. Remember roads are built between turbines for big cranes and trailers to deliver and install the turbines and there is parking underneath the turbine for maintenance workers. Having 500 4kw systems cuts into harvest revenues as do 10 20kw systems as the equivalent square footage lost to generate 1MWh is an order of magnitude larger. Also, wind turbines blades in colder climates tend to accumulate ice in the winter and thus are permitted to be located away from populated areas. Some big chunks of ice have been flung hundreds of meters. The larger the blade the further the distance you need to put your structure for safety reasons. These masts shouldn't be put on buildings (vibration) or near populations (ice).
- kbenson 11y ago
  It sounds like you are attributing the same space usage for these types of generators as wind turbines, when it appears they could be much more closely packed. I wouldn't expect ten of these to use ten times the square footage as the wind turbines. Additionally, I wouldn't expect ice to be flung as far (but I'm not sure what the oscillation is really like), but from the design, maybe ice poses other challenges to these.

reneherse 11y ago

In this case, why bring the worker to the repair site when you can bring the repair site to the worker? This new technology is in the form of a cantilevered mast. It would be a basic engineering problem to design the structure to be raised and lowered when repair is needed. The primitive model is a tabernacled mast on a sailboat.[1] [1] http://imgur.com/XwMCxbv http://imgur.com/XwMCxbv

startupfounder 11y ago
> It would be a basic engineering problem to design the structure to be raised and lowered when repair is needed. I'm a big sailer too. I used to crew on racing boats and classic schooners. Let's say we have a cantilevered mast and can swap it out "quickly". For 2MW worth of generation that would be a massive engineering feat and would mean that you have inventory not being utilized stored in the warehouse. Not just a generator or blade, but an entire system unutilized sitting around! Also most sailing masts are fairly light (aluminium) and short (30'). A 2MW wind mast would be 10x a sailing mast and hold all of the generator and electronics, not just a hollow tube that needs to be structurally sound. also masts are designed to be rigid and are held in place using shrouds and stays. A wind mast designed to move can not be held in place using guy-wires as that defeats the purpose of the dynamic wind mast. Workers on these wind farms are making between $10 and $25 each and every hour. Some specialized workers are making double that at times, but let's keep the average of $20/hr. It doesn't make economical sense even if you didn't need a crane to swap it out. And yes you would need a crane as this would be a multi-ton structure.