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Hopefield Windfarm


Wetkit
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Hi Guys,

 

I drove via Hopefield on Thursday morning on my way to Paternoster.

Huge was my supprise to notice around 36 wind turbines installed just before Hopefield!!!

These units is huge and must have been installed in the last 8 months or so, as I did not notice them the last time I went past here.

Anybody know anything regarding this?

 

Sorry the picks is not too great as I took them from my dash cam.

 

post-23-0-66299500-1385986998_thumb.png

 

post-23-0-98714300-1385987025_thumb.png

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  • 1 month later...

Drove past 31st Dec and 2nd of Jan and it looked like more than halve the turbines were already turning.

 

31st the rotation was about 6s per revolution and on the 2nd around 4s.

Would be interesting to work out the tip speed of the 50m long blade....

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  • 1 year later...

I know this thread hasn't had any posts for a year or so now but thought I'd share my knowledge about this windfarm and another one for those interested. 

 

I was the site manager for the transport, cranage and installation company on the site. We started contruction in July 2013 and were off siteby the 18th of December. If I'm not mistaken the whole farm was operational by the beginning of January.

It sure was quite a challenge to build the windfarm being one of the first big windfarms in SA. All the components of the 37 1.8 MW V100 Vestas turbines came in at Saldanha and were then transported with 8-axle single extendable trailers to the site with 610 hp Volvo trucks with special heavy duty chassis and hub reduction. The turbines had 9 oversize loads per turbine coming from Saldanha plus various smaller parts. 4 tower sections weighing between 37 and 65 tons each, the nacelle, hub and 3 blades. The heaviest load was the Nacelle(top struction with generator and gearbox in) that weighed in at 76 tons. The blades were carried on 4 axle quadruple extendable trailers. Although light weighing in at 9 tons they were almost 50 meters long thus the trailers needed to be steered separately from the truck by a steersman sitting in the rear escort vehicle with a wireless steering remote.

 

I was after hopefield also the site manager on Noblesfontein windfarm just a few kilometers from three sisters in the northern cape.  

We installed 41 1.8 MW V100 Vestas turbines on that site. The site was a nightmare with ridiculous slopes that we needed to drive on just as ridiculous road widths and conditions. There was quite a few very close calls on that site!!

If you are interested I can post some photo's of the wind farms during construction. 

 

The windfarm started to interest me in progressing toward being more independent from non-renewable energy sources and that's currently what I'm busy looking at. I will however post details in another thread for comments and advice.

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Hi Guys,

 

I drove via Hopefield on Thursday morning on my way to Paternoster.

Huge was my supprise to notice around 36 wind turbines installed just before Hopefield!!!

These units is huge and must have been installed in the last 8 months or so, as I did not notice them the last time I went past here.

Anybody know anything regarding this?

 

Sorry the picks is not too great as I took them from my dash cam.

 

attachicon.gifHopefield.png

 

attachicon.gifBlade.png

Wetkit, the photo you have of the blade on the trailer is a Siemens blade for the Eskom Cere windfarm close to Koekenhaap... Not sure if I spelled that cerrectly...

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Hi Willem,

 

Thanks for the info.

What cranes do you use to lift 76 tons to about 80m high?

Especially at Hopefield where the soil is just pure sand!

What does the tower foundation look like?

 

Funny enough, I actually drove past the Sere windfarm this Dec, again on my way camping.

Seems like I pick all the windy spots......

Guess it is the only way to avoid the crowds.

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Hi Wetkit

 

The cranes we used were the following:

Main installation crane: Liebherr LG1750 mobile latticeboom with SL boom configuration.

Aux crane was either a LTM1250 or LTM1090 being a 250 and 90 ton mobile crane.

 

The hub height was 100m on Hopefield and 80m on Noblesfontein.

 

The LG had a boom lenght of 111 meters with a lifting capacity of 109 metric tons on a 18 meter radius.

The Nacelle and Hub gets assembled on the ground and gets lifted as a unit which increases your lift weight to 101 tons including the lifting gear (76 + 22 + 3).

 

Regarding the ground conditions. The civil contractor constructed ''crane pads'', it's a 20m by 40m levelled pad which is constructed of G5 granular material with a layer thickness of 300 - 500mm.

Sand has very good compaction and carrying capabilities as long as it's compacted to specification and has a layer on the top to distribute the concentrated loads.

 

The tower foundation looks no different from the foot of a stand fan that you buy in the shops with the big round footplate. It's a big round foundation measuring +- 14m in diameter and takes in the order of 450 cubic meters of concrete which will give it weight of around a 1000 tons. There's about 30 - 50 tons of reinforcing steel in the foundation as well as a special built and imported bolt cage which runs from the bottom to the top of the foundation and where the foundation is bolted onto at the end. In the middle of the foundation the height is probably around 2- 3 meters and then taper off to the outside to just over 1 meter.

 

I'll see if have some photos at home to explain and give a better idea.

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Wetkit

 

here is some photo's for you from the hopefield and noblesfontein windfarm. You'll be able to get a better idea of the size of the turbines when looking at the photo's and directly measuring it against people and normal size cars...

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Some photos from the Hopefield site

 

Temp laydown yard close to the site entrance. You'll realise the size of the towers etc when you see them next to the vehicles..

20130913_122443_zpsea43ed9a.jpg

 

 

A complete open foundation in the sand excavation on Hopefield windfarm. The sand is excavated deeper and then recompacted before the foundation is cast.

 

20130910_090438_zps48e42f1e.jpg

 

 

The carrier and base boom section of the main installation crane (Liebherr LG1750). The legs swivel outwards to form a 16 x 16m cetre to centre footprint. The carrier as it's shown in this photo weights about 175 - 180 tons.

20130805_145429_zpsa7b9b761.jpg

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Building the main crane on one of the most difficult locations on the side of a koppie on the Noblesfontein windfarm near Three Sisters

 

20140606_175619_zps3199325e.jpg

 

 

Flat blade transport on Noblesfontein site on one of the steepest hills on site. The gradient is not really a problem for the blades because they are light, they vertical and horizontal curvature of the road is much more problematic with the blades because of the long spine beam of the trailer when extended.

 

IMG_0300_zpsde6dd71f.jpg

 

 

Second last blade installation on cranepad #2 on Noblesfontein.

 

IMG_0235_zpsa49e914e.jpg

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Transporting the 76 ton Nacelle all of a sudden becomes a bit more tricky when you attempt it on a 14 - 16% incline on a gravel road.. Front truck is a Actros 6x6 with 15 ton ballast for traction, secon truck is a 8x4 actros hooked onto the 8 axle with a fifth wheel, both trucks needs torque converter for these type of slopes in order for when you get stuck to be able to pull away again.

Total combination weight is about 140 tons.

 

IMG_0124_zps72bb0f07.jpg

 

 

Reaching the top

 

IMG_0132_zpsc83f8186.jpg

 

 

Nacelle installation with Nacelle spreader bar/lifting gear visible. The lifting gear to lift the nacelle alone weights about 3.5 tons.

 

 

IMG_0080_zps515a5b2d.jpg

 

Same as above zoomed out.

 

IMG_0082_zps9e94fb3b.jpg

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The 1st tower section gets installed with a 250ton mobile crane. It then gets grouted to the foundation where after the main crane is mobilized to the crane pad to continue with the other 2/3 tower sections, Nacelle and hub assembly and then lastly the three blades.

 

IMG_0178_zps56a8d45f.jpg

 

 

Blade offloading prior to installation. You'll note that the blade in this case is still upright in the transport frames as it came from the ship. Prior to installation the blade will be lifted from the brackets with two small cranes like in the photo, turned on it's side and laid on the ground, the root end on sleepers and the blade on sponges on top a frame. The studs is then inserted into the root end of the blade whereafter it can be installed by the main crane.

 

 

IMG_0181_zps6435a6b5.jpg

 

 

One of the foundations at Noblesfontein, you'll notice some rock in the excavation (basically it's all rock...). All foundations, roads and cable trenches needed to be blasted because of the rock. The foundation is slightly different to the Hopefield ones but not too much.

 

 

IMG_0051_zps08af4df8.jpg

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Great photo's there Willem!!!

How is the blades fixed to the centre hub? I mean, once one blade is installed, how is the remaining blades or the hub rotated to make them easy to lift and install? Lifting a blade at 45 degrees does not really sound plausable to me?

 

Can one of these fit in my garden :)

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Mike

 

 

The turbines start to turn in basicly no wind, as low as 1 - 2 m/s (3 - 7 km/h). They start generating power at 3 m/s with blades at fully pitched. The power then increase up to 100% power at 12m/s. If the wind goes stronger the pitch of the blades are reduced to not over power the turbine or let the speed run to high. They actually turn quite slow even thought the tip will move at about 200km/h. Think it was 5 to 6 seconds on a rotation.

 

These turbines are all rated at 1.8 MW but produce 2 MW on 100% capacity. And as long as the wind blows 12 + m/s they generate at full capacity..

 

However when the wind goes above 20 m/s (+- 70km/h) the turbine control system will pitch all blades to neutral and stop the turbine. Brakes are not applied but the control system wil pitch the blades every few second to make sure the rotor doesn't turn. 

 

The highest windspeed that I measured on site was 37 m/s... now that is quite strong (133 km/h). I had to hold on not to get blown away to actually take the measurement. It was only blowing like that for a short while though. Windspeeds of 20 - 28 m/s was very common on site with all works getting stopped.

 

 

Wetkit 

If you have a big enough garden then one should fit...

The blade gets about 46 high tensile M36 studs (not 100% sure about the size and number) screwed and locktighted into the root end of the blade. You lift it horizontally and install the blades by fastening the nuts from inside the hub. After a certain percentage of the nuts are torqued the hub will be rotated by a temporary motor installed on the drivetrain to align the next opening on the hub for the installation of the next blade.

You have to preferably install all three blades at a time, if you can't you have to position the blade in a certain orientation depending on how many blades are hanging as you'll get a uneven load on the bearing.

 

Another interesting fact that not everyone knows, you can't install the last tower section when the wind is above 11m/s because of the natural frequency of the tower. So if you do put it on the tower starts to sway from side to side and you can't get the nacelle on because of the movement. If you leave the last tower section on and the wind picks up more the tower can fail due to the swaying, so you need that 100 ton nacelle and hub on top to change the natural frequency of the whole tower so that it's stable in strong winds.

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Wetkit here's a few photo's for you that will show the blade installation from closer.

 

The guy in the hub is waiting for the blade to come up. There's two more guys with him that you can't see. He will be the first one to catch the blade by the studs and pull it closer the hub while also stabalizing it to fit into the hub, it's quite a tight fit. You would think he's wearing a harness but in fact he's not. There's to much wires and electronics in the hub that can be damaged by the steel on the harness and since it's rather flippen small inside the inner part of the hub they prefer to not wear a harness...

 

IMG_0305_zps66e2fbe0.jpg

 

 

On the photo below you can clearly see the studs in the blade that the guy in the hub will grab to pull it closer. and yes they all need to be lined up 100% before the blade will go in. They have temp. gear inside the hub and nacelle so that they can manually pitch the hub for the holes to line up with the studs.

 

IMG_0331_zps51209a31.jpg

 

 

Here is another picture of the blade getting installed. This is with a different main crane from Vanguard. We had two main cranes on site. The one in the picture is a Grove GTK 1100. Not the nicest crane to work with but it has some advantaged when it comes to mobilizing space.

 

IMG_0352_zpsb4df2566.jpg

 

 

This is the last piece of equipment that I loaded from site, it's a 220 ton mobile, Grove GMK5220.

The advantage being site manager was also being able to get my 275ton hydraulic boom and 250ton lattice boom crane licenses...

 

20140806_084548_zps9e0a83ea.jpg

 

 

And then last but not least, a Kudu decided to scrap my wife's car the one day that my bakkie was in for service... 5:50 one morning 4 km from site...

Happily I got out without a scratch.. the kudu was not so lucky... and off coarse the site workers utilized the meat... hahaha

 

20140525_060508_zps4d18e7ad.jpg

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