Sunday, February 13, 2011

Where The Wind Blows

With the wind already having a effect on the way my truck was handling, I wondered what was in store for me later in the day, when I would be up close and personal with the winds that blow out of the Rockies in the southwest corner of Alberta. I had been wanting too get down to the McBride Lake wind facility, located eight kilometers south of Fort Macleod for some time. With the forcast looking favourable, although with a wind-warning in the forcast for southern Alberta, I had decided that today would be a good day to head on down that way. TransAlta operates the facility and Enmax purchases the electrical output. The wind farm is made up of 114 Vestas,660 kW wind turbines. This 75-megawatt facility is one of the largest wind facilities in Canada, and produces 235,000 megawatt hours a year. You cannot appreciate how big these turbines are, until you actually get close to one! The 50 m tower is made up of rolled steel and comes in two pieces, weighing 24,000 kgs, with each blade 23 m long. The rotor on each turbine weighs 8,500 kg and is made up of three blades. The nacelle containing the generator and gearbox is about the size of a small motor home and weighs 20,000 kg! The foundation is 8.5 m deep and 5 m across, with 102 tension type bolts run the full length of the foundation. If you expand my photo, you will get a idea as to the size of this turbine, with a TransAlta pick-up, just pulling away from the base of the tower.

I had left Calgary at 5:00am so that I would arrive at the wind farm before dawn broke. By the time I turned on to highway 3, I could see color shaping up on the eastern horizon. However I was in good shape for time, as the turn-off to secondary highway 810 was immediately ahead. I soon was on the 810 headed south, with the McBride wind turbines dotting the landscape just ahead. Having done my homework on Google-Earth, I had programed my GPS with the lat-long coordinates for the wind farm, and my Garmin Nuvi was soon telling me to turn on to Township Road 80 visible just ahead. Once headed west on this backroad, I was surrounded by wind-turbines, and off to the west the Rockies loomed on the western horizon in the early morning light. By now the wind had picked up to the point that it was somewhat difficult to shoot photos, with the truck being bounced around by the winds gusting out of the west. Expand the photo and look at the antennas on my truck being whipped about by the wind! I saw one gust of 140 kph on my anemometer! The highest recorded gust speed recorded by Enviroment Canada just before 12:00 noon, at a nearby remote weather station was 148 kph!

I actually was pleased with the winds, because if your shooting photos of wind turbines, it is important to have the blades showing motion. The only way this will happen, is if the wind is blowing hard enough to turn the turbines. Then the next problem is the fact that the motion of the blades is easily stopped by the shutter speed set by your camera. Its like shooting photos of propeller driven airplanes. With too fast a shutter speed set in your camera, the results are photos that show the aeroplane with the propeller stopped! What you actually want to do is set a shutter speed on your camera that blurs the propeller blades, if not then you know what happens next, the airplane falls out of the sky! Well maybe not, but the photos are certainly ugly. The shutter speed required varies, depending on the speed that the propeller is turning at. To set the slow shutter speed that I required, I was forced to stack multiple neutral-density filters, and a polarizing filter on the front of my lens, reducing the amount of light falling on the sensor, allowing the turbine blades to blur, thus conveying motion, as in my photo of the P51 Mustang.

I had spent several hours in and around the turbines, when I ended up on a dead-end road on the west side of the wind farm. After turning my truck around, I had pulled over to shoot a photo of the Rockies to the south, that included Chief mountain looking mighty fine off in the distance. Now I have to tell you that over the years, I have had occasion to find myself in some reasonably high winds. I'm looking at the scene that I want to frame, and decided that I would step out of the truck for a better look. I opened the door to step out, and the wind tore the door out of my hand and slamed it up against the stops. I was somewhat shocked by the ferociousness of the wind at this point. I realized that I was dealing with some serious wind conditions, when I could not close the door until I rolled the window down, and even then it took both my hands to close the door. I inspected the door for damage, but it was not until later that I realized that I had sprung the door, causing a mild dis-alignment of the door-latch. Later on, upon arriving home, I managed to make the necessary adjustments, making things right with the opening and closing of the door again.
Southern Alberta, where the wind blows!

In southwestern Alberta, winds can gust in excess of hurricane force (120 km/h or 75 mph). On November 19, 1962, an especially powerful chinook in Lethbridge gusted to 171 km/h (107 mph). Gotta love it!

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