Wind Power

What is Wind Power?

Wind power or wind energy describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water), or can be converted into electricity by a generator.¹  Wind turbines can be built on land or in lakes and oceans. They are also the most cost effective when utilized in large wind farms.²

How Wind Creates Energy

A wind turbine turns energy in the wind into electricity using the aerodynamic force created by the rotor blades, which work similarly to an airplane wing or helicopter rotor blade. When the wind flows across the blade, the air pressure on one side of the blade decreases. The difference in air pressure across the two sides of the blade creates both lift and drag. The force of the lift is stronger than the drag and this causes the rotor to spin. The rotor is connected to the generator, either directly (if it’s a direct drive turbine) or through a shaft and a series of gears (a gearbox) that speed up the rotation and allow for a physically smaller generator. This translation of aerodynamic force to rotation of a generator creates electricity.²

Types of Wind Turbines

Typically, there are two different kinds of wind turbines:

Horizontal-Axis Turbines have 3 blades and operate “upwind”, and the blades facing into the wind.² They are the most common type of wind turbine used, and have several advantages. A few advantages are:³

• Blades are to the side of the turbine’s centre of gravity, which aids in stability
• Ability to wing warp, which helps with angle of attack
• Tall tower allows access to stronger wind, and allows placement in forests above the tree-line

Horizontal-Axis Turbines also have a few disadvantages:³

• Difficulty operating closer to the ground (lower winds)
• Difficult to transport and install (and expensive)

Vertical-Axis Turbines have a few different varieties, and they don’t need to adjust to point into the wind like Horizontal-Axis Turbines do.² They are more often used in residential areas. The turbine unit has 2 or 3 blades and can be shorter and closer to the ground than a horizontal system. It features a horizontal design and has 2 or 3 blades on the vertical axis.

Advantages of Vertical-Axis Turbines are:⁴

• Fewer components, therefore fewer components to wear out
• Doesn’t have to face the wind
• Safer for maintenance workers (because it is low to the ground)
• The design can be scaled down to smaller sizes
• Cheaper to produce and easier to install

However, Vertical-Axis Turbines have some disadvantages as well:⁴

• Limited efficiency because the blades do not produce the same torque at the same time
• Cannot harness higher wind speeds found at higher levels
• Vibration issues and noise produced from the turbine

What does this mean for the industry?

Wind energy provides electricity without emitting greenhouse gases or air pollutants, and uses no freshwater to generate electricity – creating a healthier environment for people and wildlife⁵. More wind energy has been built in Canada between 2008 and 2018 than any other form of electricity generation, with installed capacity growing by an average of 20 per cent per year⁶. Wind energy has been one of the fastest growing sources of electricity even globally – we will leave you with a few facts that may surprise you:

• More than 90 countries have wind energy facilities⁶
• The world’s total installed wind energy capacity by year end 2017 was 540,000 MW⁶
• Wind power is one of the lowest cost options⁶
• Wind farms can last 25+ years, and the turbines need little maintenance⁶
• CanWEA commissioned a study in 2015 that found that Canada’s wind energy operations and maintenance market will double  by 2020, which increases job opportunities.⁶

References

¹WINDExchange. (2019). What Is Wind Power? Retrieved from windexchange.energy.gov: https://windexchange.energy.gov/what-is-wind

²Wind Energy Technologies Office. (2019). How Do Wind Turbines Work? Retrieved from energy.gov: https://www.energy.gov/eere/wind/how-do-wind-turbines-work

³Gaia-Wind. (2019). Horizontal Axis Wind Turbines from Gaia Wind, Their Advantages and Disadvantages Plus the Effects of Cyclic Stress and Vibration. Retrieved from azocleantech.com: https://www.azocleantech.com/article.aspx?ArticleID=191

⁴Team Arcadia Power. (2019). Vertical Axis Wind Turbines Advantages & Disadvantages. Retrieved from arcadiapower.com: https://blog.arcadiapower.com/vertical-axis-wind-turbines-advantages-disadvantages/

⁵Canwea. (2019). Facts about wind energy and your health. Retrieved from canwea.ca: https://canwea.ca/wind-facts/your-health/

⁶Canwea. (2018). Why Wind Works. Retrieved from canwea.ca: https://canwea.ca/wind-facts/why-wind-works/