Draft National Wind Farm Development Guidelines - July 2010

likely to be obstructed. Radiocommunications services are designed to cater for any
existing obstructions in the service area. However, the construction of a new wind farm can
create new obstructions that may affect existing radiocommunications services.
Where a wind farm is proposed for development in the vicinity of telecommunications
infrastructure or in the line-of-sight of a radiocommunications service, radiocommunications
service providers and the users of their services may have concerns
about electromagnetic interference and degradation of signals as a result of a proposed
wind farm development.
A diverse range of radiocommunications service providers could be involved in any
particular development. These may include radio and television companies, mobile phone
companies, local and national utilities, the defence services, civil aviation service providers
and emergency services using microwave communications systems (such as ambulance
and coastguard). In some cases wind farm proponents may need to comply with statutory
separations from certain telecommunications equipment. For example, those associated
with aerodromes.
The scope for wind turbines to impact such systems is summarised as follows:
• The turbine tower may obstruct, reflect or refract the electromagnetic waves used in
a range of radiocommunications systems for transmission.
• The rotating blades may have similar effects, on a time-variable basis. In some cases
ghosting of TV receivers may occur where turbine blades act as an aerial to ontransmit,
or scatter, the radiocommunications signal. This can also cause impacts to
radar and other services due to scattering. This effect can be reduced by minimising
the use of turbines with metal blades or those with metallic cores or metal
components such as the lightning protection system.
• The turbine’s electrical generator itself can produce electromagnetic interference,
which may need to be suppressed by shielding design and maintenance of turbines
(although in practice, a generator is little different from a typical electrical motor and
it is quite rare for a wind turbine generator to present such a problem).
It is usually possible for the potential for the electromagnetic interference effects
mentioned above to be minimised, if not eliminated altogether through special technical
solutions and appropriate turbine siting.
F.2.2
Services potentially affected
A description of each type of radiocommunications service that may be affected by a
wind farm, together with the potential effects, is given below.
Point-to-point and broadcast (point-to-multipoint) radiocommunications
services
In general, the most susceptible of the radiocommunications services to the location of
wind turbines are analogue television services and point-to-point radio links which rely on
line-of-sight between transmitter and receiver. Any obstruction in the vicinity of a straight
line between these two points may cause interference and signal degradation. Near-end
reflections are also an issue for broadcast services such as analogue television services.
Digital television is much less susceptible to EMI from a wind farm, but can be affected in
low signal areas.
Wind farms operating within close proximity of a navigation aid or trig stations can also
impact on the operation of equipment at these facilities.
Aviation radar
Wind farms operating near airports, or in prominent positions with a line-of-sight to radar
installations, can affect radar in a number of ways. Radar line-of-sight can be hundreds of
kilometres.
Page 166 Draft National Wind Farm Development Guidelines – 2 July 2010