A framework to predict, validate and review the acoustic footprints of operating tidal turbines [abstract

B.A. Marmo (7210757)

Ben Wilson (313094)

Denise Risch (188425)

Paul Lepper (1252317)

English

Loughborough University Institutional Repository

A	framework	to	predict,	validate	and	review	the	acoustic	footprints	of	operating	tidal	turbines.		Wilson,	B;	Marmo,	BA;	Lepper,	PA;	Risch	D.			The	rapid	growth	and	diversification	of	the	tidal-stream	energy	sector	has	led	to	many	sites	and	device	concepts	being	considered	for	imminent	development.		Though	the	UK	has	been	the	focus	for	many	companies,	other	countries	notably	France,	Canada,	China	and	the	US	have	begun	to	scope,	lease	and	develop	sites.	With	tidal-stream	energy	being	renewable,	installations	are	likely	to	represent	long-term	changes	to	what	are	usually	discrete	and	biologically	important	habitats.	This	brings	significant	environmental	responsibility	in	terms	of	determining	and	mitigating	short	and	long-term	effects	on	marine	life.		A	potentially	key	impact	that	will	feature	in	most	environmental	assessments	is	the	acoustic	emissions	of	operating	devices.	Initial	drivers	were	the	determination	of	whether	devices	might	produce	sounds	loud	enough	to	produce	auditory	damage	in	sensitive	species	but	the	potential	for	barrier	effects	in	narrow	channels	is	another	obvious	concern.	Less	obvious	but	perhaps	more	important	is	whether	the	sounds	emitted	by	turbines	will	be	loud	enough	to	be	heard	by	approaching	animals	like	marine	mammals	with	sufficient	distance/time	that	they	can	avoid	harmful	collisions	with	the	moving	blades.		Currently	the	information	to	make	these	assessments	is	lacking.	In	particular,	little	is	known	about	turbine	sound	emissions	because	of	the	small	number	of	devices	that	have	been	built	and	recorded	and	the	constantly	evolving	designs	that	are	being	proposed.	Likewise,	little	is	known	about	the	levels	of	ambient	noise	in	the	coastal	high-flow	speed	waters	where	such	installations	will	be	sited.		In	this	presentation	we	will	outline	a	method	that	uses	a	combination	of	predictive	modelling,	propagation	and	empirical	at-sea	measurement	to	better	inform	assessments	of	the	audibility	of	tidal	turbines	for	marine	mammals.	For	this,	precise	information	on	the	physical	configuration	of	the	turbines,	(blades,	gearboxes,	substructure	and	so	on)	are	used	to	determine	the	characteristics	of	sound	production	of	the	component	moving	parts	and	their	modes	of	sound	transmission	into	the	surrounding	water.	Site	specific	propagation	modelling	is	then	used	to	determine	how	the	sound	will	emanate	into	the	environment	and	this	is	compared	with	on-site	ambient	sound	measurements	taken	using	drifting	recorders	at	a	range	of	tidal	states	and	water	flow	speeds.	When	put	together	these	provide	a	predictive	footprint	for	single	devices	or	arrays	and	most	importantly	(when	decision	making)	for	devices	of	different	specifications	or	design	envelopes.		In	addition	to	EIA	stage	decisions,	the	proposed	methods	may	also	inform	other	predictive	studies	of	animal	behaviour.	Particularly	those	considering	what	information	and	options	acoustically	sensitive	animals	have	when	manoeuvring	within	turbine	arrays	and	therefore	collision	risk	and	the	need	or	otherwise	for	acoustic	mitigation.	

A framework to predict, validate and review the acoustic footprints of operating tidal turbines [abstract]

https://repository.lboro.ac.uk/articles/A_framework_to_predict_validate_and_review_the_acoustic_footprints_of_operating_tidal_turbines_abstract_/9559439/files/17191382.pdf

A framework to predict, validate and review the acoustic footprints of operating tidal turbines [abstract]

Abstract

Similar works

Full text

Available Versions

Loughborough University Institutional Repository