ScanTech Offshore creates bubbles to protect sea life 

To mark World Wildlife Day (3 March), we spoke with ScanTech Offshore’s Barry Craig, Business Development Sales Manager for renewables, to find out more about how its technologies protect surrounding marine life.

The theme for this year is ‘Recovering key species for ecosystem restoration’, and with over 8,400 species of wild
fauna and flora critically endangered, it’s important to know how our operations may affect surrounding wildlife, and
whether there’s anything further we can do as a business to minimise these impacts.

Aware of its own offshore operations and potential effects on surrounding sea life, ScanTech Offshore’s Barry Craig talks about all things bubble curtain.

In light of World Wildlife Day, what measures has ScanTech taken to help protect surrounding marine life during offshore projects?
Existing noise abatement methods, such as ScanTech’s bubble curtain technology, are an effective way of reducing the spread of noise from standard impact piling operations in marine environments. Countries such as Germany and the UK, who have had noise abatement protocols for over a decade, are well-versed in the use of bubble technologies for offshore wind development, oil and gas operations and unexploded ordnance alike.
Bubble curtains are used underwater to protect marine life from loud noises during subsea operations. Ordinary
construction noises travel much more easily underwater, and sound levels can be five times higher than in open air.
This can be enough to harm and even kill sea life. However, air bubbles resonate in response to sound, absorbing
sound energy, and when formed into a curtain, they reflect the sound, effectively keeping it within the curtained
area.
The innovative technology reduces up to 90 percent of the noise emitted during the installation, lessening the harm to marine life. Up to a 30 dB reduction in sound has been measured when bubble curtains are deployed with pile driving.
They provide a double layer of sound protection to marine life in the area, equipping a large ‘noise mitigation
vessel’ with sufficient air compressors to create a double bubble curtain around the monopile. In addition, electric air compressors will be located onboard the heavy lift/pile driving installation to provide air for a near pile bubble curtain to give additional noise reduction during the installation of the monopile foundations.
A ship is typically fitted with a set of ScanTech air compressors to deliver compressed air to a flexible tube with
special nozzle openings. The tube is installed on the seabed around the locations where the sound is generated,
and the compressed class zero air creates the bubble curtain through the nozzle.

How ScanTech's bubble curtain technology works 

 Why is controlling sound during ScanTech’s operations an important factor for preserving surrounding sea life?

Marine animals rely on sound to acoustically sense their surroundings, communicate, locate food, and protect themselves underwater. Marine mammals, such as whales, use sound to identify objects such as food, obstacles, and other whales. By emitting clicks or short pulses of sound, marine mammals can listen for echoes and detect prey items or navigate around objects. This animal sense functions just like the sonar systems on navy ships. Producing and hearing sound is vital to marine mammal survival, as sound travels far greater distances than light underwater.

Underwater sound allows marine animals to gather information and communicate at great distances and from all directions. The speed of sound determines the delay between when a sound is made and when it is heard. The speed of underwater sound is five times faster than sounds traveling in air, so marine animals can perceive sound coming from much further distances than terrestrial animals. Because the sound travels faster, they also receive the sounds after much shorter delays (for the same distance). It’s no surprise that marine mammals have evolved many different uses for sounds.

What challenges have you had to overcome when looking at preserving wildlife in consideration of the company’s offshore project works?
Due to COVID-19-related border restrictions, we experienced shipping and personnel challenges. ScanTech Offshore, alongside our industry partner, Hydrotechnik Lübeck, is trialing different adaptations to its bubble curtain and compressor rig solution to push the limits of what is possible.