Wind turbines - anyone got one? any tips?

[Tom]

Hi all

We live on a very open and windy site and I'd love to make use of that by having a wind turbine. However, I know nothing at all about these. How much do they cost? Are there any grants for them? Do they work alongside mains electric or independantly? How much power do they provide? Can they run a whole house or would one be better just for, say, the stables and garage lighting? Do they need PP? I'm sorry for so many questions but, as I said, I know nothing about these and although I've looked at some sites about them I still don't understand it in laymans terms. Can anyone help or recommend a site that explains things simply? Thanks.

Jaqy

 

[MdB]

Stage 1:

Read up as much as you can on wind generation. Mini turbines (£1000 - £2000 from B&Q etc) have a poor payback period if in a good site and very very poor payback if poorly sited. Their green credentials has also been questioned if you look at the amount of energy required to produce, though I know little on this.

Stage 2:

Get yourself an anemometer from ebay or the like to find out what your actual wind speeds are like. An auto logging device would be best.

The energy generated is proportional to something like the cube of the wind speed. This means light and medium winds generate little and its the strong winds you need. Very strong winds generally overpower the turbine and it has to waste some of the energy available. Combining the anemometer readings together with data from turbine manufactures data sheets to see what you will actually generate.

Stage 3:

Finally make a decision on whether to buy or not.

 

[Aidan]

Stage 1:

Read up as much as you can on wind generation.

This seems a good starting point;

http://www.scoraigwind.com/

 

[tony]

Look at the Navitron Webiste and forum.

Best Regards

Tony

 

[Jane Smith]

We live off-grid and have a Proven 6kW wind turbine which supplies all our power and has also supplied most of our heating this winter (although it is now snowing and the wind has dropped, so we're going to burn some oil tonight).

I've posted a bit about it here, especially in the "Great Winter Heating Experiment".

You need to know your local average windspeed, which you should find by googling; and you need to have a nice, uncluttered landscape in which to put up your turbine. Your view of a smooth landscape might not be what's required--trees, walls, houses and hillsides all add to turbulence.

Grid-connect wind turbines are cheaper to install than off-grid ones, but they do switch off if there's a power failure in your area: it's a safety-feature, apparently.

If you put one of ours up you'd pay about £13,000 minus a grant of £5,000. You'll need a lot of space, away from your house: we need about 25m working area to winch ours up and down.

Go and do some online research, then come back here once you know a bit more, as it's such a big subject to cover I can't tell you everything! Or ask specific questions, and I'll do what I can to answer you. Is that OK?

 

[Penners]

we need about 25m working area to winch ours up and down.

Is that for maintenance, Jane? How often do you have to do this?

 

[Jane Smith]

Penners, we winch it down once a year to check that all the nuts and bolts are tight enough and that there is no damage to the rotor blades, that sort of thing. When it first went in it went up and down several times, as we had a few problems with it. It's thirsty work.

The mast is 9m long; each rotor is just over 2m long, so total height is about 11m, so you need 11m to lay it down, plus the distance from the foundations to the winch-point, and a few extra meters to work the winch. The winch-point is a few meters away (10? 12?) from the turbine on the opposite side, away from where it goes down. We use a hand-winch with a gin-pole to winch the whole thing down. Here's a photo: click it to enlarge.

 

[Penners]

Jane - looking at the very interesting picture, I've just realised that there doesn't seem to be any form of rear vane to turn the turbine automatically into the wind. How is this accomplished?

Actually, I noticed the same thing on some big industrial turbines today, as I drove on the A14 past a wind farm near Kettering (10 turbines I think). They have nothing in the form of a vane. Are the heads (or indeed the whole masts) turned electrically?

 

[Jane Smith]

Nope, Penners, our turbine only needs the wind to work because it has (pause for Penners to find a safe place to sit) a self-exciting alternator.

The back of the hub (in the photo, the big round black bit at the top, above the rotor blades) faces into the wind when it's blowing. Because of the shape of the hub and the rotors, the whole head swivels to keep the back of the hub facing into the wind. The rotors are flexible, so when it blows very hard they flex out of the wind, so reducing the turbine's exposure to the wind, and slowing it down. So, it's got no gears, which means it's quieter, and has less gubbings to go wrong. Clever, eh?

Commercial wind turbines need to be connected to the mains as they need some electricity to get them going. They do NOT have self-exciting alternators, and so need an alternative form of excitement. Boom-boom.

 

[Penners]

Sorry, Jane, I'm being thick (pause for nods of agreement).

I still don't understand what ensures that the whole rigmarole is facing the right way to make efficient use of the wind. Presumably it won't work if the wind is coming at it sideways?

Old-fashioned smock mills had a "tail" vane or rotor that rotated the head to face the wind - as does that silly little thing that B&Q sell. Yours (and the industrial jobs) don't seem to have this.

 

[Jane Smith]

OK, Penners, in words of one syllable. Especially for you.

Wind turbines usually face the rotor-end of the top bit into the wind. They use those tail-vanes to do this.

On ours, the rotor-blades are flexed a tiny bit so that they point very slightly away from the hub (which is the big bit that they are fixed to). Imagine trying to force a large, slightly cone-shaped object into the wind. It's not going to like it. And if it's fixed onto a 360 degree swivelling thing (which is what the hub is), it's going to prefer to turn away from the wind. Which is what happens.

And when it's really windy the springs which attach the rotors to the hub stretch and allow the blades to bend even further into a cone-shape, so reducing the swept area of the blades, and slowing them down so you don't get too much power belting out of the thing.

Is that a help? Hope so.

 

[Taff in Glaws]

Pah, the green eyed monster has taking me over and Mrs Taff wants to know why we got to sell up and go and live in the country cos of some self excitor thing I been rambling on about that I've seen on the net.

 

[NT]

The main rotor acts as the tailvane as well, ie the rotor sits behind the mast in operation, not in front.

NT

 

[NT]

quote DWB

> Do they work alongside mains electric or independantly?

Either. But theres not much sense getting a windmill if youve got mains. Spending the money on other measures would save more.


> How much power do they provide?

depends on machine and local wind.


> Can they run a whole house or would one be better just for, say, the stables and garage lighting?

AIUI theyre best as one part of the whole system, ie alongside solar pv. Reason is a single mill may generate next to nothing for many days in a row.


> I'm sorry for so many questions but, as I said, I know nothing about these and although I've looked at some sites about them I still don't understand it in laymans terms. Can anyone help or recommend a site that explains things simply? Thanks.

your best starting point is to find out the windspeeds for your site. Only a minority are windy enough to get reasonable payback.


NT

 

[Penners]

OK, Penners, in words of one syllable. Especially for you.

OK Jane, despite the fact that you actually used lots of those silly bubble things, I now understand. Yaaaaay!

Thank you for your (almost) patience!

 

[Jane Smith]

Ah, Penners, my dear, you're welcome. If only Mr Grimsdale could be persuaded to come here, then I could get REALLY patient.

The turbine is belting round today and we've got a foot of snow on the ground. I'm stuck in all day as we've only got one four-wheel-drive, which David has taken to work, and the Clio is buried up to its door handles. I should be working but the snow is too distracting. I suspect I'll be posting a bit today.

 

[skier-hughes]

we've got a foot of snow on the ground. ............. the Clio is buried up to its door handles.

I know you said David wrecked the clio on the driveway, but surely he didn't squash it down :lol:

Graham

 

[Jane Smith]

Keep up, Graham, it was an Audi that David wrecked on the driveway. The Clio was only very slightly written-off, but it got better thanks to the nice insurance people.

We've had two Jewson's trucks written off on the driveway. They will keep swerving to avoid the potholes, and ending up in the ditch. They don't deliver to us any more.

 

[skier-hughes]

I've dug ditches to stop people driving on the grass.

Well my car gets muddy driving on the track, yes but the track is just getting wider and wider as people drive on the grass.

I tried a sign at the beginning of the drive.

Didn't work.

Having to tow out a delivery driver and my father in law fgrom one of the ditches seems to have worked... plus it's stopping the track deteriorating so quickly as well, diverting the rain off it in stages.

Still we only have to wait for the 19th Feb, as the council are relaying the road we go up onto then and we are getting all the scalpings!!!

Graham

 

[Jane Smith]

Ours is getting wider and wider too, for the same reason. But we can't dig ditches the whole way along, it would take too much work and wreck the cattle grid.

My father in law won't drive up it any more, though--it scares him, and his car gets dirty. So there are benefits!