Background
Terma are perhaps best known for providing in-fill radar for mitigating the effects of wind turbines on radar systems. The increase in the height of onshore turbines in excess of 150 metres means that the lighting of turbines becomes mandatory in the United Kingdom and other countries. This can present a significant visual impact at night which requires mitigating.
Mitigating Visual Impact
There are a number of ways of mitigating the impact of aviation lighting on wind turbines. These may only be acceptable in some jurisdictions and some situations. The methods include:
- Reducing light intensity in good visibility
- Designing lights to minimize downward spill
- Limiting the number of lights
- Only switching lights on when aircraft are in the vicinity – radar controlled lighting allows this
UK Lighting Requirement
The requirement for lighting of wind turbines in the United Kingdom is set out in Civil Aviation Authority Policy Statement “Lighting of Onshore Wind Turbine Generators in the United Kingdom with a maximum blade tip height at or in excess of 150m Above Ground Level”. The requirement is for 2000 Candela red lights mounted on the wind turbine nacelle and intermediate 32 Candela lights mounted on the wind turbine tower.
Radar Controlled Lighting
An X Band Terma SCANTER radar is installed in or near the wind farm so that it can detect aircraft approaching the wind farm. When aircraft are detected at night the wind turbine lights are illuminated. When the aircraft disappears the lights are extinguished.
Frequently Asked Questions
Q. Is this system approved by the UK CAA?
A. Not yet – but the system is likely to get the go-ahead in remote settings.
Q. Can one radar be used for multiple wind farms?
A. Yes it can. It needs to be sited and specified so it can see aircraft approaching all wind farms from sufficient range.
Q. Can radar controlled lighting mitigation be combined with other forms of mitigation?
A. Technically yes – subject to approval by the regulator. Combining intensity control with radar control can be particularly effective.
Q. Does using the Terma system tie developers?
A. No. The system works with any remotely controlled light and can work on any turbine type.
Q. Are there other suppliers of radar controlled lighting?
A. Yes there are. Other systems include OCAS, PARASOL and Vestas Intelilight.
How Can Pager Power help?
Pager Power can advise wind developers on finding effective lighting solutions that minimise visual impact at night. For more information please call Mike Watson on 01787 319001.
References
https://publicapps.caa.co.uk/docs/33/DAP01062017_LightingWindTurbinesOnshoreAbove150mAGL.pdf
https://www.terma.com/surveillance-mission-systems/wind-farm-solutions/obstruction-light-control/
https://pxhere.com/en/photo/1458265
