Another take on wind turbines

[JumbleDuck]

It does matter here because an understanding of the Second Law is a defence against all perpetual motion machines.

Fair point.

 

[Mistroma]

Fair point.

The journalist may well claim that you are talking about Scottish law and it doesn't apply under English law. Unfortunately, I can almost bring myself to believe they'd consider the idea sufficiently to Google.

I'd agree with JD about effects of sloppy journalism. My worry is that a politician might read the article and decide to pour some public money into a trial. Politicians usually have even less STEM knowledge and only know it ticks boxes for re-cycling and renewable energy.

O2 seem to be trialling a few of these projects and perhaps that's a good idea if even one produces results. However, I suspect they may not be real trials.

e.g. O2 are offered free turbines on poles if sited in a public spot at the entrance. The public see them turning in a light breeze, read the blurb on a sign underneath and are impressed that they contribute power to O2. Of course they aren't generating much even when spinning in a light breeze and the power is only used for a few LEDs to illuminate the sign they are reading.

 

[paddleking]

This is a very weird thread.

The Guardian says: "Independent research commissioned by the company has found that each turbine installed along a motorway could generate as much electricity as 20 sq metres of solar panels."

Who is that research by? Presumably a scientist and not one of you lot? The Guardian probably saw that research. I bet The O2 paid for that research. You'd do well to find out rather than defaming a journalist.

The journalist's article doesn't say the O2 uses the same power as 23 homes. Are you deliberately misunderstanding her?

The O2 parent company, AEG, says it expects to install more of the mini turbines across its stadiums worldwide.

Do you think, just maybe, that a billion dollar company knows more about electricity generation than guys on a forum? Or perhaps you think the turbine company just turned up at The O2 with a drawing on a napkin and a massive organisation said 'Here, take our money.'

Do you think a company like that would risk its reputation in such a way?

Come on, get real.

Make sure you have facts before you start hurling accusations and insults.

 

[Mistroma]

This is a very weird thread.

The Guardian says: "Independent research commissioned by the company has found that each turbine installed along a motorway could generate as much electricity as 20 sq metres of solar panels."

Who is that research by? Presumably a scientist and not one of you lot? The Guardian probably saw that research. I bet The O2 paid for that research. You'd do well to find out rather than defaming a journalist.

The journalist's article doesn't say the O2 uses the same power as 23 homes. Are you deliberately misunderstanding her?

The O2 parent company, AEG, says it expects to install more of the mini turbines across its stadiums worldwide.

Do you think, just maybe, that a billion dollar company knows more about electricity generation than guys on a forum? Or perhaps you think the turbine company just turned up at The O2 with a drawing on a napkin and a massive organisation said 'Here, take our money.'

Do you think a company like that would risk its reputation in such a way?

Come on, get real.

Make sure you have facts before you start hurling accusations and insults.

Not facts, basic physics. I think that you will find the figures you mention on the Alpha-311 website with no indication of their source. In fact the company don't even give their own contact details let alone a research source. I don't think their figures can count as facts without detail or at least a source.

Can you please give details of your own calculations to show that the claims are at least possible? I'd be happy to look at the calculations and assumptions for the claimed output from a 68cm high vertical turbine.

The company claimed that the installation of 10 of the 68cm vertical turbines could generate up to an estimated 87,600 kilowatt hours a year.

A single turbine could therefore generate up to an estimated 8,760 kilowatt hours per year (continuous 1kW output). It is of course possible and you only need to estimate the constant wind speed required to achieve the claimed output. Possibly around 100mph

 

[Mistroma]

Perhaps someone would like to check my calculations. I looked out some old calculations I carried out in relation to my Rutland 913 to estimate the approx. efficiency of that item.

Wind is air with a given density moving at a velocity and a turbine "collects" some of this energy by reducing the speed of wind passing through the device.

The calculation is pretty simple.

P Power (Watts)
C Power coefficient (relates to how efficiently the device can remove enery from air in motion)
A Area of device able to capture moving air m2
p Air density Kg/m3
V Velocity m/s

Power = ½ * C * A * p * V * V * V

Rearranging gives velocity in m/s as:

V = (Power / (½ * C * A * p ))^(1/3)

Different values used for C (0.2, 0.593 and 1)
Power is 1000 as claimed output is a steady 1kW (24kWh every day)
Area is estimated to be 0.105 sq.m (0.68*0.3/2)
Air density estimated as 1.225 Kg/m3

I've converted the m/s values to mph and using a variety of efficiencies you get:

96mph with 20% efficiency (reasonable estimate)
67mph with 59.3% efficiency (unlikely as it is the Betz limit)
56mph with 100% efficiency (completely impossible)

I doubt O2 are going to get a steady 90 mph wind every single day.

I note that the other claim was: "Independent research commissioned by the company has found that each turbine installed along a motorway could generate as much electricity as 20 sq metres of solar panels." At least that's only 38% of the earlier claim.

20sq.m would be a 3kW panel array (20 x 150W panels). Average daily output near South of England would be about 9kWh per day over the entire year.
However, you'd still need a steady 65-70 mph wind to get that output.

Have I made any glaring errors in my calculations? I haven't looked at this since I did my initial calculations a few years ago.

 

[Alan S]

It seems that A-311 were not the first with the idea of using traffic turbulence.
Capture Mobility in Scotland came up with a more beleivable claim of up to 300W frpm a 1.2m turbine in 2017, but even with the backing of Shell, they appear to have sunk without trace.

 

[JumbleDuck]

This is a very weird thread.

And how nice of you to join it, with your very first post.

The Guardian says: "Independent research commissioned by the company has found that each turbine installed along a motorway could generate as much electricity as 20 sq metres of solar panels."

Who is that research by? Presumably a scientist and not one of you lot?

Not me, though for my standard consultancy rate I'd be very happy to take a look at their numbers. And I find it very hard to believe that any genuine scientist would confirm, let alone produce, the cobblers reported.

Do you think, just maybe, that a billion dollar company knows more about electricity generation than guys on a forum? Or perhaps you think the turbine company just turned up at The O2 with a drawing on a napkin and a massive organisation said 'Here, take our money.'

Do you think a company like that would risk its reputation in such a way?

Greenwashing - Wikipedia

 

[JumbleDuck]

Have I made any glaring errors in my calculations? I haven't looked at this since I did my initial calculations a few years ago.

Looks mostly fine to me and broadly aligns with my own earlier calculation. The only doubt I have is on the turbine size: I think 68cm is the diameter but th elength is unclear: the article (in a stunning example of journalistic care and accuracy) says "Alpha 311 turbines were originally designed to be larger, at just nearly 2 metes in length" so if these are 1 -2 metres in length and the blades protrude by 15cm (say) beyond the core that would be an effective area of 0.15- 0.3 m. Slight more than your estimate, but not enough to change the conclusions significantly.

Here's the companies own picture of the O2 installation. 1kW average, 365 days per year, from one of these? Bwahahahahahahaha.

Here, for comparison is commercially produced vertical axis wind turbine.

Narrower, but similar length of blades. Maybe a bit shorter. In F10 it's good for 65W.

 

[Mistroma]

And how nice of you to join it, with your very first post.

Not me. And I find it very hard to believe that any genuine scientist would confirm, let alone produce, the cobblers reported.

Greenwashing - Wikipedia

I wondered if Alan S had been rumbled with his email queries.

I'm a bit groggy today with pan killers and lack of sleep. Lower back pain for last 3 days. Let me know if I made any bloopers in my rough calculations above. Only school level physics but I could have slipped up somewhere. We've both indicated that the claims are "optimistic" and I thought it would help to show some working for actual figures. The wind strengths feel about right to produce quoted output for that size of vertical turbine.

 

[Mistroma]

Looks mostly fine to me and broadly aligns with my own earlier calculation. The only doubt I have is on the turbine size: I think 68cm is the diameter but th elength is unclear: the article (in a stunning example of journalistic care and accuracy) says "Alpha 311 turbines were originally designed to be larger, at just nearly 2 metes in length" so if these are 1 -2 metres in length and the blades protrude by 15cm (say) beyond the core that would be an effective area of 0.15- 0.3 m. Slight more than your estimate, but not enough to change the conclusions significantly.

Here's the companies own picture of the O2 installation. 1kW average, 365 days per year, from one of these? Bwahahahahahahaha.

Here, for comparison is commercially produced vertical axis wind turbine.

Narrower, but similar length of blades. Maybe a bit shorter. In F10 it's good for 65W.

I had taken the size from the mention of 68cm vertical turbines and the drawing shown on Alpha 311 turbines - local renewable energy for the world. It doesn't give dimensions but 0.68cm high didn't look miles away for the blades. I had not taken a close look at the O2 picture and can see that they do not look much like the ones on the Alpha site.

I could probably do some rough size estimates from basic geometry and assumption they had 68cm diameter as they will have higher output but not enough to make a significant difference. Actually, it's easier to look at it another way. You could get 1kW output from an 8m high 2m diameter turbine with 30% efficiency and constant 20 mph wind. No idea how they'd get 30% and it's way larger than the ones in the picture. Plus a nice steady 20mph breeze all year.

 

[Alan S]

All the figures calculated by JD, Mistroma and myself are in the same ballpark, a thousand miles from Alpha's ballbark.


I emailed alpha 311 this:

I have looked further into the somewhat sparse data on your website and have a few misgivings. For example these two statements:

quote
"One A311 Vertical Axis Wind Turbine can generate as much power as 24 solar panels.24 solar panels measuring 1m2 will produce 6KW per day."

quote
"Electric vehicles will turn our turbines and which will power more electric vehicles, in a beautiful never-ending cycle."

24x 20% efficient 1m2 panels will produce 4.8 kW peak power under ideal conditions.
Typical daily energy output in UK averaged over a year would be about 12 to15 kWh.

Either way the first statement, whether you mean 6kW of power, or a daily energy output of 6kWh, does not seem correct.

The second statement looks like pure nonsense.

I regret that without further verifiable data, this is one opportunity I shall have to let pass by.

I wish you well in your enterprise and shall watch with interest.

They emailed back:
All our figures are based on a study conducted Dr Andy Young, head of thermal and fluid engineering at Leeds University.

The second statement you mentioned is part of our future vision, so while it's definitely not feasible yet, it's where we want to get to!

 

[Neeves]

Slight drift here,

JD - you will be upset to learn that The Guardian offers free access to their publication here. I had no idea you had to subscribe. We enjoy an Australian edition, covering news of the day for Australia and then all the other reports common to the UK and USA editions. We can also access directly, free, the UK edition (and I assume the US edition though I have no reason to look).

The Guardian does look for donations - but they are not a requirement, yet, for access.

Jonathan

 

[JumbleDuck]

Slight drift here,

JD - you will be upset to learn that The Guardian offers free access to their publication here. I had no idea you had to subscribe. We enjoy an Australian edition, covering news of the day for Australia and then all the other reports common to the UK and USA editions. We can also access directly, free, the UK edition (and I assume the US edition though I have no reason to look).

The Guardian does look for donations - but they are not a requirement, yet, for access.

Jonathan

Sorry, I wasn't clear. The online version is free here as well. It's the printed on paper (you know, dead trees squashed flat, like in the olde days) ones which cost money and support the websites.

 

[Neeves]

Sorry, I wasn't clear. The online version is free here as well. It's the printed on paper (you know, dead trees squashed flat, like in the olde days) ones which cost money and support the websites.

Ah! Live and learn - I thought they had gone all digital and marvelled that they were able to fund - anything. Now I understand.

Thanks

 

[JumbleDuck]

Ah! Live and learn - I thought they had gone all digital and marvelled that they were able to fund - anything. Now I understand.

Thanks

No problem. You may have been thinking of the Independent, another British broadsheet which gave up print in 2016 and now exists - somehow - only as website. Tt spawned a lightweight offshoot, the i, which has bounced around various owners and is now heading steadily down and to the right in the Daily Mail stable.

 

[sgr143]

Sorry, I wasn't clear. The online version is free here as well. It's the printed on paper (you know, dead trees squashed flat, like in the olde days) ones which cost money and support the websites.

Though you can pay them money for various grades of "membership", which I do because it means I get online access to the crosswords. Oh my, age is creeping up on me.

 

[JumbleDuck]

Though you can pay them money for various grades of "membership", which I do because it means I get online access to the crosswords. Oh my, age is creeping up on me.

I thought all the Guardian crosswords were free? I do the cryptics, quicks, everyman and quiptic every week if I can.