Energy, Mines, and Resources

Wind Energy

Wind Energy

What is wind?
Wind power starts with the sun. When sun heats the ground, the air around that ground warms up and rises. As the hot air rises heavier, cool air rushes in to fill its place. That rush of air is wind.

What is wind energy?
Air is made of gas particles. These particles move quickly when it is windy producing kinetic energy, which can be captured. Wind turbines absorb this kinetic energy turning it into electricity.

How does a wind turbine make electricity?

Rotor – Wind moves the rotor transferring energy to the turbine. The rotor is connected to a shaft that spins when the rotor spins. The shaft transfers the mechanical energy of the rotor to the generator.

Generator – The generator converts the energy from the spinning rotor into electricity.

Nacelle – The nacelle (housing) protects the gearbox, generator and other components of the wind turbine.

Tower – The tower places the rotor in the path of the wind. The tower at the Yukon College Renewable Energy demonstration site is a guyed tilt-up tower. It has guy wires securing the tower to the ground, and can be tilted down to ground level to repair the turbine. (See the Renewable Energy Live Feed button at the top of this page for more information on the Yukon College Renewable Energy demonstration site.)

Anemometer – the anemometer tells the turbine's computer how fast the wind is blowing. This turbine is designed with a shape that allows it to automatically face into the wind.

Inverter – The wind turbine at the Yukon College Renewable Energy demonstration site generates a DC current and uses an inverter in the nacelle to create an alternating current. Direct current (DC) is a flow of electricity in one direction, then in the other. Households use AC due to its ability to be transmitted over long distances with minimum energy loss.

What factors affect wind energy?
Wind power (Pw) is governed by the equation where ρ is the density of air, A is the area covered by the wind turbine blades and U is the wind speed:

Air density – As air gets colder, density increases and more air is available. For example, -20°C could produce 16% more energy than +20°C.

Blade area – The greater the blade area, the more wind that is captured. For example, increases to blade length by 40% can double the amount of energy produced.

Wind speed – As wind speed increases, the power of the wind increases by the power of three. For example, every time the wind speed doubles, the power of the wind is eight times greater. The turbine at the Yukon College Renewable Energy demonstration site needs winds of approximately 15km/h to begin producing wind energy. Winds greater than 70km/h cause the turbine to stall to protect itself.

Higher is better  – Locating a wind turbine on a hill or tower increases the amount of wind energy available. For example, increasing a tower's height from ten to 50 meters can double the available wind energy.

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Balance of System
Depending on the specifics of the renewable energy system, a number of other pieces of equipment may be needed to complete it; these are called the Balance of System (BOS) Requirements.

Renewable energy sources can either be autonomous or grid-connected. Autonomous systems generate power for the user only, while grid-connected systems generate power for the user, but are connected to the electrical grid.

When a system is grid-connected it does not require batteries because the local power company will provide power if the wind isn't blowing or the sun isn't shining. If a grid-connected system produces more power than the user needs, that power can be used by others who are connected to the electrical grid.

When a system is net-metered is means that the power company pays the owner of the system for the extra power generated by their renewable energy system. The system at Yukon College is grid-connected and net-metered. In this case Yukon College recieves credits on its bill when it produces extra power.

Batteries – Batteries may be used on some systems to store extra energy during high production. This energy can then be used at a later date or when the weather is not conducive for energy production.

Inverter – The inverter converts DC to AC power. Direct current (DC) is a flow of energy in one direction. Alternating current (AC) flows first in one direction, then in the other. AC is used in household electricity because of its ability to be transmitted over long distances with minimum loss.

Cables – Cables are used to connect all the various components of the system.

Disconnect switches and circuit breakers – switches and breakers are built into the system to protect the various components from overloads or electrical problems.

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Wind Energy in Yukon

wind turbines

 

Conditions for a successful utility scale wind generation
In order for a utility scale wind energy project to be successful the following conditions must exist:

  • Consistent wind speeds of about 22 Km/h;
  • Access to an electric power grid;
  • Large capital investment;
  • Power markets that can adjust to wind supply variations; and
  • Ability to produce power at costs equivalent to competing technology (diesel).

Yukon wind research findings
Monitoring the wind resource in the Yukon has led to the following three conclusions:

  1. Wind speeds are greater at higher elevations.
  2. Wind energy is usually greater in the winter months when electrical demand is highest and hydro potential is lowest.
  3. All sites tested in the Whitehorse area — Haeckel Hill, Mount Sumanik and Flat Mountain — have wind speeds greater than 25/km/h considered adequate for wind farming.
  4. In some parts of the world concerns have been raised regarding the possibility of birds striking wind turbines. Five years of bird studies at the Haeckel Hill site gave the wind turbines a clean bill of health. It has been determined that migration routes for waterfowl are in the valley below the turbine site.

Rime Ice
Both of Yukon's turbines suffer operational problems during the winter due to icing, specifically rime icing. Rime icing is a white frost-like build-up that can often be seen on branches and trees around open water and often occurs on Yukon Mountains when a cloud contacts the mountain or ridge. Under these conditions solid objects accumulate ice that ‘grows’ into the wind. This kind of icing condition makes it very difficult for wind turbines to operate.

In order to help minimize the effect of icing on the turbines YEC has made a number of modifications to the system:

  • Installing wide heating strips to create an ice free blade area and increase efficiency;
  • Replacing the pole-supported power line with buried cable to eliminate power line outages;
  • Installating a fully heated anemometer and wind vane to eliminate rime icing problems with these two instruments; and
  • Painting a black-coloured coating on the blades to encourage ice shedding.

Future of Wind Energy in the Yukon
YEC, private individuals and private industry continue to evaluate Yukon sites for their wind generation potential. As the cost of petroleum based fuels continues to rise wind energy becomes an increasingly attractive option for power generation in remote communities and for remote industrial and residential operations.

Yukon Wind Research Papers and Presentations

yukon wind resource map viewerYukon Wind Resource Map Viewer
This map shows the average wind speed at locations around the Yukon. Note that the wind speeds were measured at varying elevations above sea level and above ground level and that the wind data collection methods also varied based on the data source.

Go to the Yukon Wind Resource Map Viewer.

 

Wind Prospecting Service
The Energy Solutions Centre's Wind Prospecting Service can determine your wind resource potential so that you can make a decision about investing in wind generation equipment.

 

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