Page 10 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
Receptor Potential Mitigation
Fish and shellfish ƒ Undertake iterative reviews of the Draft Plan taking account of information available from
other trial deployments elsewhere and monitoring data collected during implementation of
early developments under the Plan. Co-operation with regulators in France and the Channel
Islands should be pursued to ensure that as much as possible can be learnt from early
deployments of tidal energy devices;
ƒ Avoid construction during sensitive seasons, e.g. breeding/peak egg laying/spawning
seasons, in feeding grounds and during migration times of migratory fish;
ƒ Good construction practice to minimising noise and vibration;
ƒ Minimise use of high noise emission activities such as piling; and
ƒ Produce a cable laying plan to minimise EMF at or above the seabed. This will include
consideration of cable design and installation (e.g. bury cables where practicable).
Ornithology ƒ Undertake iterative reviews of the Draft Plan taking account of information available from
other trial deployments elsewhere and monitoring data collected during implementation of
early developments under the Plan. Co-operation with regulators in France and the Channel
Islands should be pursued to ensure that as much as possible can be learnt from early
deployments of tidal energy devices;
ƒ Mitigation that is likely to be required to protect marine mammals from collision risk will also
protect diving birds. These include:
o Automatic shutdown of rotary mechanism by proximity sensor to avoid death or injury by
collision with tidal infrastructure; and
o Establishment of an active sonar system which detects marine mammals at sufficient
range from the turbine to allow a precautionary shutdown to occur automatically.
ƒ Restrict piling (if required) to periods of low species activity periods within annual and diurnal
cycles as appropriate to avoid excessive displacement of species by underwater noise
caused by infrastructure installation (piling); and
ƒ Where appropriate to the local species ensuring that piling (if required) commences using an
agreed soft start procedure; the gradual increase of piling power, incrementally over a set
time period, until full operational power is achieved. The soft-start duration should be a
period of not less than 20 minutes. The soft-start procedure will vary according to hammer
and pile design and other factors.
Marine mammals and
turtles
ƒ Automatic shutdown of rotary mechanism by proximity sensor to avoid death or injury by
collision with tidal infrastructure;
ƒ Marine mammal monitoring undertaken for a defined period of time during initial operation
with potential turbine shutdown when a mammal is within 50m of turbine rotors;
ƒ Regular surveillance for carcasses and post mortem evaluation of carcass stranding and
assessment of cause of death;
ƒ Establishment of an active sonar system which detects marine mammals at sufficient range
from the turbine to allow a precautionary shutdown to occur automatically; and
ƒ Iterative reviews of the Draft Plan taking account of information available from other trial
deployments elsewhere and monitoring data collected during implementation of early
developments under the Plan. Co-operation with regulators in France and the Channel
Islands should be pursued to ensure that as much as possible can be learnt from early
deployments of tidal energy devices;
ƒ Restrict any piling to periods of low species activity within annual and diurnal cycles as
appropriate to avoid displacement of species by underwater noise caused by infrastructure
installation (piling);
ƒ Where appropriate to the local species, ensure that piling commences using an agreed soft
start procedure; the gradual increase of piling power, incrementally over a set time period,
until full operational power is achieved. The soft-start duration should be a period of not less
than 20 minutes. The soft-start procedure will vary according to hammer and pile design and
other factors;
ƒ Ensuring that piling activities do not commence until half an hour has elapsed during which
marine mammals have not been detected in or around the site. The detection should be
undertaken both visually (by Marine Mammal Observer) and acoustically using appropriate
Passive Acoustic Monitoring equipment. Both the observers and equipment must be
R/4001/7 (vii) R.2129