Meeting Europe's renewable energy targets in harmony with - RSPB

RENEWABLE ENERGY TECHNOLOGIES AND ECOLOGICAL SUSTAINABILITY 55
during migration, breeding and post-breeding
periods (Haas et al., 2005).
Retrofitting or replacing “killer poles”
“Killer poles” should be replaced or retrofitted for
bird safety. If all medium-voltage “killer poles”
were rendered safe, numerous endangered species
of large birds, like storks, eagles and eagle owls,
might be allowed to recover and start to repopulate
lost ranges (Haas et al., 2005). Attempts to reintroduce
these birds will only be successful if the
main mortality factors, such as electrocution and
collision, have been excluded as far as possible.
Fitting of rejectors and insulation
Suitably arranged rejectors can be used to deter
birds from perching on poles and towers, thereby
reducing the risk of electrocution. These can be
retro-fitted to dangerous arrangements or used on
new equipment to ensure that birds do not perch in
areas where they might be at risk. Insulation
sheathing, hoods or plastic caps may be retrofitted
or factored into the design of new infrastructure, to
increase the distance between exposed conducting
cables/wires and earth sources.
National standards and guidance
It is possible to reduce the risk of electrocution
significantly without raising the costs of installing
power lines to unacceptable levels (Haas et al.,
2005). This can be achieved by developing
construction criteria and principles for bird safety
which ensure a high standard of design with bird
safety in mind (international agreements on bird
safe power lines are discussed in Box 22). This
applies to new constructions and for retro-fitting
kits. National governments are recommended to
pass suitable legislation, which makes technical
standards for bird safety legally binding.
Better design of new power lines
In various parts of the world, different technical
solutions for bird safety are under test and
evaluation, so far with moderate results (Haas et al.,
2005). Unfortunately, many electricity transmission
companies do not seem to be aware of the progress
that has already been achieved for bird safety in
relation to power lines. Adopting safe power pole or
tower constructions can effectively reduce the risks
posed to birds.
Undergrounding sections in sensitive areas
Fortunately, with continuing technical progress
many types of high-risk transmission lines will
eventually be removed. In addition, favourable
trends can be reported from the low- and mediumvoltage
networks of some utility companies, which
have made the step to change from above-ground
power lines to underground power lines (Haas et
al., 2005).
Where sensitive locations cannot be avoided power
lines should be undergrounded where the terrain
is suitable and ecological impacts are acceptable.
However, this remains an expensive option for
high-voltage lines and will therefore continue to
be used sparingly. It is important that all of the
potential impacts of burying power lines are fully
considered when plans are drawn up, as impacts
on sensitive habitats might be significant.
Markers
The use of markers to increase the visibility of
power lines and earth wires has been shown to
be effective at reducing collisions of many species
(Jenkins et al., 2010). There are many designs and
some are more effective than others. There is also
variability in terms of the lifespan of different
markers. Consideration of the need to renew
markers on a regular basis should be made, or
a design selected which has a long shelf-life.
Removal of the earth wire
Many large power lines are designed to carry a
single earth/neutral wire above the current-carrying
ones. This earth wire tends to be thinner and less
visible. Often on encountering power lines birds
will flare upwards on recognising the obstacle, but
fail to clear the earth wire and collision ensues.
Removal of the earth wire can significantly reduce
the risk of collision (Jenkins et al., 2010).
Habitat management
There are considerable opportunities for ecological
enhancement through the management of habitats
beneath and around power lines to benefit wildlife.
There may be opportunities to mitigate (or
compensate) for losses elsewhere, through
managing habitats to benefit species which are not
considered at risk of collision. Habitat management
to deter large raptors might be partially successful if
it reduces attractiveness of the areas to these birds.
On the other hand, power poles and towers offer
perching, roosting and nesting sites for some large
birds. Bird-safe power lines enable birds, like raptors,
storks and ravens, to nest in otherwise treeless
landscapes, which may benefit these species.