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Wind Power Without the Mills

forbes.com

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Re: Wind Power Without the Mills

#41

Post by lambdaelite »

insertnickname wrote: post #32
lambdaelite wrote: post #28

Earlier quoted context omitted.

A problem with the estimates in the U.S. is that turbines disproportionately affect legally-protected birds, and so the numbers are suspected to be severely under reported.

So what? If they're too stupid not to fly into a giant blade, then maybe it's ok that they die.

A selfish reason to care is that apex predators like birds of prey are useful as indicators for the health of an ecosystem. Take the case of DDT as an example.

A less selfish reason is that bad things happen to the rest of the ecosystem when you mess around with apex predators.

Re: Wind Power Without the Mills

#42

Post by scblock »

bpodgursky wrote: post #22
scblock wrote: post #15

Again? AGAIN? Another "no blades! save the birds!" technology that's little more than a concept. There are constantly amazing technologies just around the corner that will definitely totally be awesomely better than existing 3 bladed horizontal axis wind turbine technology. And they'll always be less expensive than current technology somehow. Trust me, getting the cost right at this stage of the technology curve is a…

Decades? I would say it took centuries at least. The basic design hasn't changed since the middle ages.

Truth. To clarify, I was specifically referring to wind turbines that generate electricity.

Re: Wind Power Without the Mills

#43

Post by wlesieutre »

boombip wrote: post #36
barryfandango wrote: post #26

Earlier quoted context omitted.

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.

Yeah, until the retraction mechanism breaks.

No problem, just put the retraction mechanism in a lifting mechanism to lift it out of the ground for maintenance!

Re: Wind Power Without the Mills

#44

Post by frik »

It's called the "Magnus effect" and is not new at all: http://en.wikipedia.org/wiki/Magnus_effect

There are airplanes and boats that use this technique too: http://en.wikipedia.org/wiki/Rotor_ship , http://en.wikipedia.org/wiki/Flettner_airplane , http://en.wikipedia.org/wiki/Alcyone_(ship) , http://en.wikipedia.org/wiki/E-Ship_1 ,

Wind mills and green energy is great, so go for it - just don't try to patent the "Magnus effect".

Re: Wind Power Without the Mills

#45

Post by startupfounder »

ChuckMcM wrote: post #39
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…

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…

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).

Re: Wind Power Without the Mills

#46

Post by posnet »

scblock wrote: post #15

Again? AGAIN? Another "no blades! save the birds!" technology that's little more than a concept. There are constantly amazing technologies just around the corner that will definitely totally be awesomely better than existing 3 bladed horizontal axis wind turbine technology. And they'll always be less expensive than current technology somehow. Trust me, getting the cost right at this stage of the technology curve is a…

Another example of interesting developments. But this one at least seems to be scalable to 1MW.

http://www.thinkerstools.net/powerpack.htm

Re: Wind Power Without the Mills

#47

Post by startupfounder »

kbenson wrote: post #30
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…

> 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 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

Re: Wind Power Without the Mills

#48

Post by kbenson »

startupfounder wrote: post #45
ChuckMcM wrote: post #39

Earlier quoted context omitted.

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…

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 these.

Re: Wind Power Without the Mills

#49

Post by startupfounder »

sliverstorm wrote: post #24
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…

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")

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.

Re: Wind Power Without the Mills

#50

Post by sliverstorm »

startupfounder wrote: post #49
sliverstorm wrote: post #24

Earlier quoted context omitted.

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")

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 :)
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