March 19, 2013

Guelph turbine brakes in south end wind

Chris Seto, Mercury staff | Tue Mar 19 2013 |

GUELPH – When driving past the recently built Emergency Services Centre, it’s hard to miss the five metre-tall wind turbine perched on top of the roof. If you’re driving by at the right moment, you may even get to see it spin.

The wind turbine was a $50,000 addition to the city building which was designed in accordance with LEED standards. Generating power as it spins, the eight-blade turbine feeds electricity back into the facility, helping the building save on operating costs.

But since the windmill was commissioned in April 2011, it’s been spinning less than 60 per cent of the time.

Rob Kerr, the city’s corporate manager of community energy, said the turbine has a mechanism to protect it from spinning out of control in strong winds. An adjustable sensor mounted on the unit employs a brake automatically when the blades get spinning too fast. After the brake is engaged a certain number of times, the turbine will lock itself down, preventing the blades from moving at all. It will then have to be manually reset.

This auto-shutoff mechanism combined with nine days the turbine was down for maintenance, and the occasional day when there is no wind at all, he said having the windmill spin 50 or 60 per cent of the time is reasonable.

Kerr said readings were taken earlier this month that showed the turbine has been operating for 9,088 hours since it was officially commissioned.

This means over the past 22 months, the windmill has only been spinning for 12.5 of them. He said the city is still in the process of calibrating these readings to make sure they’re accurate.

Sharolyn Vettese, spokesperson for Wind Simplicity – the creator of the turbine – said the auto-brake sensor can be adjusted to allow the unit to spin at faster speeds. She said the maximum speed the units can take is roughly 350 revolutions per minute. She was unable to comment on the wind speed it would take to make the turbine spin that fast.

She said the Windancer 7 model was installed with the sensor at a low level, making it stop in lighter winds. She was unable to say at what wind speed the turbine would engage its brake. Vettese also said the optimal wind speed for the turbine is between 12 and 14 km/h.

Environment Canada reports the average wind speed at Waterloo Region Airport, around 20 kilometres from the Clair Road centre, to range between eight and 16 km/h.

Kerr also said since it first started spinning, the turbine has produced 581 kilowatt hours of electricity.

To put this in perspective, Ontario’s Independent Electricity System Operator said one kilowatt hour is roughly equal to someone blow drying their hair three times or baking a birthday cake. The typical Ontario household uses between 800 and 1,000 kWh a month, the operator reports.

“It all contributes to the performance of the building,” Kerr said in a phone interview on Monday.

He said the driving force behind putting the turbine on the roof was to help the building achieve Leadership in Energy and Environmental Design certification, an internationally recognized benchmark for design, construction and operation of green buildings.

The facility, which houses police, firefighters and paramedics, was built partly from recycled construction materials. It also features a solar water heater, bicycle storage and showers to encourage staff to run or bike to work. Kerr said the city is hopeful for the facility to be recognized with a silver LEED accreditation later this year.

He said even though the turbine is only spinning part of the time and the amount of energy it generates is not very much, the amount it spins does not have a large affect on achieving certification. LEED looks at the overall energy savings of a building. The turbine is a contributing element in the facility’s design, he said.

When the building first opened in June 2011, the city estimated the facility would use around 50 per cent less electricity and 30 per cent less water than conventional buildings of the same size. Kerr said staff are in the process of compiling stats from the building but do not yet have real numbers to report. He said early indicators look positive.

He said because the turbine’s auto-shutoff sensor is adjustable, “we can continually tweak it to perform more, and we intend to do that.”

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