A three-phase project began in fall 2012 on the Bearspaw Operations Workplace Centre site to see what options we have to harness the power of the wind and sun on City of Calgary work sites.
Comparing large and small wind turbines
Industry definitions generally describe a "large" wind turbine as over 50 kilowatts (kW) in size and any turbine 50 kW and under as a "small" wind turbine.
Image A (below) shows a 50 kW small wind turbine on the right. This typical example is 46 metres tall. Most 50 kW small turbines are less than 50 metres tall to the tip of the highest blade.
In comparison, most large wind turbines are more than twice as tall (see image A below, left). Most of the large wind turbines installed in southern Alberta are about the same size as the image on the left.
Image A: large turbine at the left; small turbine on the right.
Different sizes of small wind turbines
Small wind turbines (less than 50 kW) come in several sizes. The smaller the size, the less energy they produce.
Small wind turbines in the 50 kW range can generate enough electricity for up to 24 houses for a whole year with consistent winds of less than 22 km/h.
Most 50 kW small turbines are less than 50 metres tall to the tip of the highest blade. A typical 50 kW example (image B, right) stands about 46 metres high.
Small wind turbines less than 3 kW in size can be less than 13 metres high. Image B (below, left) shows a turbine that is 12.2 metres high.
Small wind turbines are most often found in urban centres - referred to as "urban turbines."
Image B: 3 kW turbine (left); 50 kW turbine (right).
How tall is a 50 kW small wind turbine?
A typical 50 kW small wind turbine is less than 50 metres tall to the tip of the highest blade. Image C (below) shows a 46 metre-tall small wind turbine.
- Image C (below, right) shows the existing trees onsite are about 27 metres high - shorter than the small turbine.
- Some towers for electrical transmission lines are about the same height, while others are taller. See image C (below, left).
Image C: transmission lines near the site (left); typical height of a 50 kW turbine (centre); approximate size of the existing trees on site (right).
Comparing the size of the temporary wind assessment mast
Image D (below) show the height of the mast installed in November 2012 in Bearspaw OWC for the wind assessment study - about 25 metres (70 feet) tall – compared to a typical 50 kW small wind turbine.
Image D: Typical height of 50 kW turbine (left); temporary wind assessment mast (right).
Comparing the size of a familiar Calgary building
Image E (below) shows the height of the Calgary Tower – a familiar landmark for Calgarians – compared to the height of a typical 50 kW small wind turbine.
The small wind turbine stands less than one quarter as high as the Calgary Tower.
Image E: For comparison, the Calgary Tower (left); the typical height of a 50 kW turbine (centre); typical trees onsite (right).
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