Wind power: An inside look at how the turbine at Exhibition Place keeps spinning
Fri Jun 15 2012
John Spears Business Reporter
Love them or loathe them, wind turbines are hard to ignore; and the turbine at Toronto’s Exhibition Place could well be the most visible in Canada.
 The owners of the tower – the 400-plus-memberWindShare Co-operative, and Toronto Hydro – took the Toronto Star on a tour of the lakefront landmark.

Like any tower, the turbine starts at the base, sunk 10 metres into bedrock.
The main shaft of the tower is made of three steel sections, stacked on top of each other and reaching 65 metres into the air – about 30 stories high.
It’s topped by the “nacelle,” a steel segment sheathed in fibre glass, to which the turbine blades attach.
Getting to the nacelle in the turbine at the Ex is an old-school journey.
From bottom to top, according to the turbine operators, there are 198 “vertical stairs.” A normal English speaker would call them 198 ladder rungs.
Newer turbines have elevators, but building standards didn’t allow them when the Ex turbine was constructed.
To haul cargo to the top of the tower – turbines need lots of lubricant – there’s a rope and pulley.
 Climbers are attached to a safety rope on the ladder, and there are several platforms on the way up to stop for a breather.
 Standing on the platforms, climbers can feel the floor vibrating under their feet.
 That’s all in a good cause, says co-op member Gary Zavits, who leads the tour. The tower is engineered to sway and vibrate to dissipate energy that would otherwise shake up the electronic equipment.
The nacelle sits atop the steel tower, and the whole assembly can swivel. An anemometer mounted on top measures wind direction and speed. It sends the information to a control system that activates three motors.
The motors connect to gear wheels that crank the nacelle around so it’s facing directly into the wind.
The three blades, each 24 metres long, rotate 21 times a minute at optimal speed. That means if you’re standing on top of the nacelle, a blade will whiz past your nose about once a second.
The blades turn clockwise, if you’re facing the turbine with the wind at your back.
Small motors inside the conical section to which the blades attach directly can vary the angle of the blades so they always turn about the same speed.
It takes a breeze of about 9 kilometres an hour to move the blades. Anything over 71 kilometers an hour is considered too strong; in that case the motors turn the blades at right angles to the wind so they don’t move.
The cone holding the blades is surrounded by a donut-shaped apparatus.
This is the business part of the turbine – the actual generator.
It holds an array of strong magnets that spin with the turbine blades.
Held stationary in a ring around the whirling magnets is a mass of conducting coils. As the electro-magnetic field created by the magnets spins in the wind, it produces a current which is transmitted through a cable to ground level. It’s then sent to a nearby transformer station and fed into the regular electricity grid.
(The Exhibition Place turbine is now a decade old. Newer turbines, which generate three or four times the output, generally use the whirling blades to turn an axle connected to a gear assembly that drives a generator.)
This turbine generates enough to power 200 to 250 homes.
Economics has not been kind to this turbine.
Originally contemplated as a 750-kilowatt turbine, its current capacity is 600 kilowatts – one-third or one-quarter the capacity of most turbines you’ll see in the Ontario countryside.
The co-op’s initial offering statement projected an annual output of 1,800 megawatt hours per year. Actual output has been less than that: 1,000 to 1,400 megawatt hours.
Since 2007 the owners have received payment of 11 cents a kilowatt hour for its output under a contract with the province.
There have been no pay-outs to co-op members since it started operating in 2003.


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