Wednesday, 21 November 2012

Blowing in the Wind

21 November 2012 was declared as Renewable Energy Day 2012.  As part of that Infigen Energy ran a series of visits to the Woodlawn Windfarm between Bungendore and Tarago.   I thought it would be interesting to get up close and personal with the turbines, about which I have blogged in the past, so registered and joined in.

The visit was rather pleasantly unstructured.  I had thought we would be talked at a lot, but instead after a gathering at Bungendore we drove out to the Woodlawn site, and basically asked our guides questions as they occurred to us.  It meant not everyone learnt everything but was a very open process.

The site is near Tarago and thus quite a bit away from the Capital Windfarm (also run by Infigen)  near Lake George.  The Woodlawn site was chosen for the open day because the site is owned by a company (who run a refuse handling business on the site of the former Woodlawn Mine nearby) and can thus handle busloads of tourist more easily than the private landholders involved with the Capital site.

Our guides were 3 young blokes from the Sydney operation which monitors both sites (and indeed others in other States) 24/7/365.  Most of the operation is managed automatically with the turbines starting up when the wind gets high enough to turn them and turning off when it gets so strong as to risk damaging them.

I'll start with a very wide shot from Google Earth showing the shadows of the turbines.
The area around the turbines is grazed by sheep and apparently they like the shadows of the turbines when the weather is hot.  The sheep form turbine patterns!  When it is cold they huddle by the transformers at the base of each tower.
We stopped here, 2km from the towers, and could not hear any noise from the turbines.  There was a fair lot of ambient wind noise as it was a tad blowy - as shown by the dust blowing in the next shot.
We got up close to a tower, where the turbine had been turned off so that we could check it out.  We were about 500m from the next turbine, which was running and could hear a 'whup' from that but it was really not intrusive.
That image shows the sculptured shape of the 40m long blades.  They reminded me of the 'Bird in Space' sculptures by Constantin Brancusi.  On the subject of birds one of our guides commented that they get about 7 bird strikes pr year, all logged and officially reported.  I suspect this is a fair undercount, since:
  • a bird hit by the rotors could get flung a fair way; and
  • in a rural setting like this there will be many entities (foxes, feral cats, raptors and corvids) which will demolish the remains in a very short time.
That being said, my belief is that:
  • the number of birds killed by these turbines is way less than the number killed by carbon induced climate change; and
  • if a bird gets whupped by a turbine blade it deserves a Darwin Award.
I was quite impressed by the blades being transported by truck from Sydney.  Apparently the vehicle they travel on has independent steering at the back to 'juggle' (my word) around tight corners.   By way of example, this image shows a bend in Tarago (at the Loaded Dog pub) and the yellow line is as close as Google Earth can get to 40m long (and I am not allowing for the length of the prime mover)!
Any other way of getting to the site would involve corners tighter than this so obviously not an exercise undertaken without some thought!

This next shot is inside the tower looking up the ladder.  This only goes about 10m and there is a small elevator for the next 70m.  The metal bin (with yellow sticker) holds the cables for the elevator as it goes up. There are 14 technicians on duty to maintain the whole array from day to day: half are motor mechanics, the others electricians

While I was looking at this, the wind veered and the nascelle yawed, to ensure the blades (if they had been running) kept the optimum interface with the wind.  This was quite noisy inside the tower but not outside.  Apparently it takes 25 minutes for the nascelles to turn through 360 degrees.  If they turn in one direction for 810 degrees (ie 2.25 revolutions) the cables get too twisted so the system gets turned off and the nascelle counter-rotates to get things straight.  Obviously computers play a but part in this!

This next shot is straight up at the base of the nascelle.  Notice the small trap door to the left of the round circle.

That is the escape hatch!  If a fire breaks out when the technicians are up there they use abseil ropes to come out of the hatch and get down to the ground.  They receive training in this!  I think I would pass.

We were the last group of the day and as we walked away they started up the turbine again.  Up close it was still silent but when we were about 100m we entered a noisy zone, but by the time we were at the parking lot it was impossible to hear the turbine over the ambient wind.

Possibly because I think they are a great idea - way better than fracking about with CSG - I found this quite an interesting visit.  I'd be interested in climbing the tower, but the thought of the required training for an 80m abseil cancels than as a prospect.

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