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Wind Power Without the Mills

forbes.com

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Re: Wind Power Without the Mills

#51

Post by kbenson »

startupfounder wrote: post #47
kbenson wrote: post #30

Earlier quoted context omitted.

> 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…

> 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 th…

Thanks for the references on how this would function. I wasn't really assuming a 45 degree oscillation, I wonder what oscillation they they are assuming in their projections. I imagine a single "blade" would be moved less by the same amount of wind, but there are probably plenty of factors I'm not considering. I imagine scaling these up you have some pretty crazy engineering problems to overcome, like how to deal with the repeated strain at the base.

In the end, it may be that the better use for these is indeed the 40' 4kW version for the back yard. I could see that pairing with a bunch of chained Tesla powerwall units to good effect.

Re: Wind Power Without the Mills

#52

Post by startupfounder »

kbenson wrote: post #48
startupfounder wrote: post #45

Earlier quoted context omitted.

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 syste…

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 the…

MWh/sq.ft.

I am attributing larger footprint usage to trying to generate a similar power output given current wind mast technology. 10 wind masts alone don't take up the same space as 10 classic turbines, but the the number of wind masts necessary to generate the equivalent output of 10 classic turbines is greater that 1:1 due to wind swept area per turbine.

Re: Wind Power Without the Mills

#53

Post by startupfounder »

sliverstorm wrote: post #50
startupfounder wrote: post #49

Earlier quoted context omitted.

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.

I actually slip up and omit a "p" from time to time, but it's really the "e" - "rapel" vs "repel" - that threw me :)

And I suck at spelling :)

Re: Wind Power Without the Mills

#54

Post by reneherse »

startupfounder wrote: post #20

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…

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

Re: Wind Power Without the Mills

#55

Post by qbrass »

david-given wrote: post #31
frobozz wrote: post #23

This says 'Because there is no contact between moving parts, there is no friction. Therefore no lubricant is required. No replacement of spare parts either.' However, there are animations that show it wobbling. This implies that it's made of a flexible substance. I'm not being so pedantic as to suggest that the fibres or crystals etc. of the substance are moving parts (though surely there is friction between them), b…

How to make tall, stiff objects wobble safely is pretty standard technology these days --- all tall buildings do it, and very tall skyscrapers are carefully tuned and damped to wobble in exactly the right way. This is partly because of wind, and partly earthquakes. Here's a terrifying video of a skyscraper farm in Japan swaying gently after an earthquake in 2011. https://www.youtube.com/watch?v=EQaHyY9-Fuw So I'd say…

Build them out of skyscrapers.

Re: Wind Power Without the Mills

#56

Post by startupfounder »

reneherse wrote: post #54
startupfounder wrote: post #20

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…

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

> 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.

Re: Wind Power Without the Mills

#57

Post by olau »

startupfounder wrote: post #47
kbenson wrote: post #30

Earlier quoted context omitted.

> 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…

> 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 th…

About maintenance of wind turbines: but when you compare the actual costs of O&M on wind turbines they are actually still pretty cheap compared to traditional energy sources, and it will likely get cheaper as the tech matures and common problems are addressed through improved manufacturing and better tools.

But I agree that for places on earth close enough to the equator to have plentiful solar irradiance, also in the winter, solar looks like it is going to win hands down.

Re: Wind Power Without the Mills

#58

Post by startupfounder »

olau wrote: post #57
startupfounder wrote: post #47

Earlier quoted context omitted.

> 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 th…

About maintenance of wind turbines: but when you compare the actual costs of O&M on wind turbines they are actually still pretty cheap compared to traditional energy sources, and it will likely get cheaper as the tech matures and common problems are addressed through improved manufacturing and better tools. But I agree that for places on earth close enough to the equator to have plentiful solar irradiance, also in th…

> it will likely get cheaper as the tech matures and common problems are addressed through improved manufacturing and better tools.

Yes! They are very cheap compared to coal fired power plants. During University I helped prepare one of the first wind turbines (call the wind furnace[0]) ever built to be shipped to the Smithsonian. This initial prototype turbine was built in 1972. Now 43 years later we have massive adoption of the technology and we are still ironing out the bugs. Big O&M cost are blade repair, gearbox and generator swapout and yes they are getting cheaper, but most of the these costs are the cost of the crane coming in.

Modern turbines are fairly new to the market and we are still collecting data on how the components last over time. Most manufacturers, Siemens, GE, Gamesa, etc provide a 3-5 year warranty. Their incentive is to produce as many cheap components as possible that last the 3-5 years so they don't have to replace the parts under warranty.

Wind turbines are very complex feats of engineering, solar panels on the other hand are simpler to make than sheetrock and as we scale that technology and come up with creative financing options that guarantee savings market penetration is going to be even greater than wind even in regions far away from the equatorial region.

creative finance is the key to clean energy scale and adoption, not technology.

[0] http://www.umass.edu/windenergy/about/history/furnace

Re: Wind Power Without the Mills

#59

Post by startupfounder »

kbenson wrote: post #51
startupfounder wrote: post #47

Earlier quoted context omitted.

> 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 th…

Thanks for the references on how this would function. I wasn't really assuming a 45 degree oscillation, I wonder what oscillation they they are assuming in their projections. I imagine a single "blade" would be moved less by the same amount of wind, but there are probably plenty of factors I'm not considering. I imagine scaling these up you have some pretty crazy engineering problems to overcome, like how to deal wit…

> I imagine a single "blade" would be moved less by the same amount of wind, but there are probably plenty of factors I'm not considering.

Modern wind turbines have a cut in wind speed of maybe 3.5m/s and my guess is that these wind masts don't have a cut-in speed. So in low wind resource regions they may be effective at capturing market share because they can produce electricity with only a slight breeze.

> I imagine scaling these up you have some pretty crazy engineering problems to overcome, like how to deal with the repeated strain at the base.

Modern turbines have plenty of vibrations that the tower and foundation have to deal with. I was in the nacelle of a wind turbine when a surprise small tornado came to town, we were full on rodeo mode with the tower swaying back and forth. That being said on a day to day basis most of the forces are countered with the rotating mass (someone else can explain this better than I) so the turbine doesn't transfer much horizontal load to the foundation.

With the wind mast there would be most horizontal load on the foundation as there is not another blade or two to counteract the motion and thus it would require a larger foundation.

If you want to buy a 4kw turbine you can find one used for under $7k which is much less than this new technology. As better 3 bladed tech comes online there will be a larger second market for used turbines and thus might be a better economic option then buying unproven new wind mast technology. Pairing used or new wind tech to batteries can really benefit the offtaker depending on the marketplace.

Re: Wind Power Without the Mills

#60

Post by drewm1980 »

dates wrote: post #2

Also relevant are these awesome wind kits google is developing: http://www.google.com/makani/

The makani team is serious business. They keep building larger and larger prototypes and are nailing their predicted power curve every time. They have internal expertise to build (almost) everything in house, and have already demonstrated autonomous operation. They recently unveiled the wing from their under-construction 600 kW model, which should fly sometime this summer.
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