Wind turbine impact assessment for industry

In certain circumstances, wind turbines, either as single units or grouped together in a wind farm, can negatively affect navigational systems if installed within a certain distance of an aerodrome. Although wind turbines do not transmit or radiate RF signals other than the generation of background noise, they can still affect radar signals in a number of ways including shadowing, mirror-type reflections, clutter or signal scattering. The impact of a radar receiving such a signal could cause critical information about a target (i.e. aircraft) to be lost or cause the target to disappear suddenly and reappear in a different location on the screen. This impact on performance causes great concerns to flying operations in terms of safety to military and civilian personnel and aircraft. In addition, the large blades of wind turbine towers located near an airport are a hazard to low approach and low altitude flights, as well as gliders and skydiving training activities.

The joint publication produced by the Radio Advisory Board of Canada (RABC) and the Canadian Wind Energy Association (CanWEA) (reference) describes how wind turbines can interfere with the operations of air defence and air traffic management radar systems or become physical obstructions to flying operations.

As a matter of public policy, the Department of National Defence / Canadian Armed Forces (DND / CAF) does not generally oppose the development of wind farms and other sources of renewable energy unless they adversely impact military operations, safety, readiness or training of CAF.

The determination of whether or not a proposed turbine or wind farm may create an unacceptable level of interference with existing radar is very complex and it is not possible to categorically determine if unacceptable interference will occur unless a site-specific analysis is undertaken.

To avoid any potential difficulties, the following process is recommended at an early stage in the wind farm development process:

1. The wind turbine project Proponent creates documentation showing:
   • Maps of the location of the proposed wind farm and all the wind turbines
   • Latitude and Longitude (NAD83 or WGS84) of each wind turbine using the Wind Turbine Submission Form (XLS, 50 kB). The following information is required in order to complete the Wind Turbine Submission Form:
     • Turbine Number
     • LAT (dd mm ss.ss)
     • LONG (ddd mm ss.ss)
     • Ground Elevation (meters)
     • Nacelle Height (meters)
     • Rotor Diameter (meters)
     • Total Height (meters)
   • Ground or base elevation above Mean Sea Level for each turbine
   • Height of each nacelle above ground level
   • Diameter of the rotating blades
   • Blade material
2. The Proponent contacts +WindTurbines@forces.gc.ca with this information to determine if there is any possibility that the proposed wind farm may impact any radar in the area.
3. If it is determined that a given installation may have an impact, the Proponent and the Department of National Defence authority then undertake the necessary studies and non-regulatory mitigation measures to resolve the issue to the mutual satisfaction of both parties involved.

Note: The process outlined above applies specifically to Department of National Defence assets. However, civil air navigational systems are similarly affected by wind turbines and as such, proponents should contact NAV CANADA’s Land Use Department for an assessment of their systems.

As a starting point to any project analysis, reference serves as a useful industry guide of generally acceptable separation distances (referred to as consultation zones) between wind farms and various military systems.

The table below provides general area sizes around specific equipment that would require consultation between a potential developer and the Department of National Defense.

Wind Turbines
D Aero Rdns
1 Canadian Air Division
PO Box 17000 Station Forces
Winnipeg MB R3J 3Y5

E-mail: +WindTurbines@forces.gc.ca

This contact is for technical assessment and impact on National Defence Radars only. All general public inquiries should be directed to Public Affairs.

Email: +WindTurbines@forces.gc.ca, attention DND FSM