Wind turbines are becoming increasingly popular as sources of renewable energy. And just as with airports, the preferred locations are far enough away from populated areas to minimise nuisance. If placed too close to airports, however, they create hazards to aviation, only some of which can be mitigated. Here we examine four issues, other than the widely discussed issue of interference with airport radar and radio, that are central to the topic.
The problems are greatest for general aviation and at heliports.
Growing trend
Around the globe, governments are placing more and more wind farms to help meet renewable energy targets. Not only is their number multiplying; as the technology develops, wind turbines are also growing taller.
Only some of the hazards of wind turbines placed too close to airports can be mitigated. If their location means air traffic operating to and from the airport cannot be handled safely, the only option is placing the wind turbines elsewhere.
What exactly are the issues?
For large airports, where proper spatial planning provides for a correct application of obstacle limitation surface regulations, hazards from wind turbines nearby are relatively minor. The problems are greatest for general aviation and at heliports.
Wind turbines are obstacles
The low-level airspace around an airport’s runway or at a heliport that is needed for aircraft to climb or descend must be protected from obstacles, especially in case of engine loss. Like buildings, wind turbines are obstacles and should, as a rule, not be permitted to penetrate the obstacle surface.
Wind turbines create turbulence
As the blades turn to generate power, they create turbulence downwind. For large, heavy transport aeroplanes, this turbulence is not a great threat. For smaller general aviation aeroplanes and helicopters, passing behind a wind turbine introduces turbulence that can, in extreme cases, cause an unsafe flight.
With turbulent air being produced only when the wind turbine is operating, this hazard is easier to mitigate at a low-intensity heliport, for example, than a busy airport. The jury is still out as to what is a safe distance for aircraft to avoid turbulence from wind turbines in operation. Conservative estimates currently prescribe up to six times the turbine’s diameter.
Wind turbines can just be in the way
A wind turbine that does not penetrate an obstacle surface or introduce turbulence may still present a special hazard for helicopters and general aviation due to its position. For example, wind turbines placed close to the point of a turn in an approach flight path might block critical visibility for the pilot during a manoeuvre close to the ground.
Whilst this specific hazard is admittedly subjective, case-by-case safety solutions could be defined with good communication between aviation and wind energy stakeholders.
Wind turbines are bright lights at night
This issue is complicated by the interests of a third party: the local community. Aviation stakeholders expect wind turbines to be marked with lights as per international requirements, but the wind energy sector is very conscious that local communities find the lights a nuisance.
Automatic detection systems that activate obstacle lights only when aircraft are in the vicinity are probably the best technological solution available today. However, balancing aviation safety and the wishes of local communities is something all parties, including regulatory authorities, must work on further.
Working out obstacles
When planning wind farms and turbines near airports, it is critical that planners and energy companies work together with the airport and air traffic management to analyse each individual issue for aviation operations and to find ways to avoid or mitigate them.
Using a tool such as OLET, for example, can help determine workable obstacle limitation levels around the airport, and airspace analysis and planning can help pinpoint critical points under flight paths to avoid or change.
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Dont the cause reflexion on rhe groundradar and radiofrequency? The so called whab- whab- whab sound?
Airborne radar and radio interference are both known issues with regard to wind farms. This article focuses on a number of other, less well known issues.
The excellent post. i can collect the more relative matters from it. The aviation and good relationship is needed for all. The cause reflection and sound is getting more reliable in this post. The excellent writing and covered with quality assurance also. The post is very clear and getting more knowledge tips. Thanks for given this post for the audience to read and know about relationship value. Lot of magazines are tells about that
Hi, I own a Private airport and it is certified by the state and FAA. Turbines 650ft above ground level at a mountain height of 1750ft puts them at 2300ft. That is my pattern altitude. My pattern is only 1500ft away from some of the turbines. Can you provide any info on this. I think it might be deadly. I’m in a Piper Cub.
The article completely ignores the issue mentioned by Ton Maas – radar interference. NOT ground radar, but primary ATC radar. This is a complex issue that puts serious limitations on the placement of wind turbines. Very few countries have clear guidelines and methods. The issue applies to both civil and military aviation.
We chose to focus on issues other than radar for this blog as much as been written on the topic. I would agree with you that few States have clear regulations.
The key word here is PROPER SPATIAL PLANNING.
There are a lot of airports around the world with buildings and radio towers all around them. This is very important to mention.
If an airport needs the space and turbines cannot be placed on a persons property. The property owner should be compensated for the use of his airspace and his loss of income from not being able to have turbines placed on his land.
The subject of property rights is rarely mentioned in any of these discussions.
A wind park of 8 giant tourbines are being built at Haramsøya, Norway. This is close to Vigra AirPort Ålesund which lies on the already wind stricken west coast.
Any concerns regarding turbulence or other thoughts?
The growing focus on environmental sustainability across the globe is the major driver of the global wind turbine market.
Responding to RCR – property owners do not own unlimited airspace above their property. According to the Supreme Court, landowners own or have dominion over “at least as much of the space above the ground as he can occupy or use in connection with the land..” Airplanes are not trespassing because they are flying in what Congress has declared as the public highway. There is no set foot height, but generally the government considers the public highway to start around 500 feet in uncongested areas.
Thanks for the comment. This may vary from country to country, but in general, a landowner has no ownership of the airspace above their land. The doctrine of cuius est solum, eius est usque ad coelum et ad inferos often does not apply, Unfortunately only in Dutch, but Prof. Koops at Universiteit Leiden has put a good ovrview of this matter together: https://www.vervoerrecht.nl/sites/default/files/Egbert%20Koops.pdf