And Why Textiles Can Surprisingly Be Part of the Solution
The energy transition is happening largely at sea. Anyone sailing along the Belgian coast will notice it immediately: offshore wind farms have become a permanent feature of the North Sea landscape. They provide green electricity and are essential to meet climate goals.
But beneath the water’s surface — where we hardly look — a very different story unfolds. For many marine animals, a wind farm is not a visual landmark, but a source of noise. And especially during construction, this can be a major problem.
The Loudest Phase: Pile Driving at Sea
An offshore wind turbine is usually installed on a monopile: a gigantic steel pole driven tens of meters into the seabed. Pile driving is done with a hydraulic hammer that repeatedly strikes the pole.
To humans, it may sound like a dull knock in the distance.
For fish, marine mammals, and plankton larvae, it is something completely different.
Underwater, sound travels extremely far — much farther than in air — and much more efficiently. For marine animals, sound is not a minor sense but their primary way of perceiving the environment. They use it for:
- Communication
- Orientation
- Hunting
- Avoiding predators
Research in Belgian waters (by Jan Haelters, Elisabeth Debusschere, and Dick Botteldooren) shows that especially pile driving during the construction phase produces intense, impulsive sound waves that can be harmful to fish and marine mammals. (ILVO)
What Happens to Animals?
1. Behavioral Changes
Marine mammals like harbor porpoises avoid the area around construction sites. Studies show their presence decreases hours before pile driving begins due to increasing ship and construction noise.
This might seem positive – “they swim away”, but in reality, it means a loss of habitat and feeding areas.
2. Stress and Physical Damage in Fish
Experimental research on young sea bass showed that impulsive noise from pile driving:
- Causes acute stress reactions
- Disrupts physiological processes
- And in some cases can result in internal and external injuries
These effects are strongest near the source (<50 m), but early life stages of fish — larvae and juveniles — are particularly sensitive.
This is crucial: these are the populations that later form fish stocks.
3. Not Only During Construction
Even when wind turbines are operational, they produce continuous underwater noise comparable to constant ship noise.
So:
Construction phase = extremely loud
Operation = long-term background noise
Both have ecological consequences.
Why This Is Such a Difficult Problem
We are in a paradox:
Offshore wind energy is needed to combat climate change.
But climate measures must not create new environmental problems in marine ecosystems.
Current offshore wind innovation is therefore not only about energy yield — but also about acoustic impact.
Enter Textiles
This is where it gets surprisingly interesting for the textile sector.
Blocking underwater noise is not a classic civil engineering challenge, but essentially a materials problem.
Water and steel conduct vibrations extremely well.
Air and porous structures do not.
In other words: the best sound barrier is not concrete… but a controlled combination of air, structures, and membranes.
Greenov’s SubSeaQuieter: A Textile-like System Underwater
A good example is Greenov’s SubSeaQuieter.
This system uses a flexible, multilayer membrane structure — essentially a technical textile — placed around the monopile during pile driving. At least two Belgian companies were involved in its development: 3D Weaving en Sioen.
How does it work?
The membranes are filled with air, creating a barrier between water and the noise source. This “impedance break” strongly dampens sound waves. (Greenov)
In this context, impedance basically means how easily a material transmits sound. Water and steel have high acoustic impedance, air and soft materials low.
An impedance break occurs when a sound wave passes from a high-impedance material to a low-impedance one, e.g., from steel (pile) to an air-filled textile membrane.
A large part of the sound energy is reflected or absorbed, and less penetrates into the water. In plain language: the sound “breaks” and weakens because of the material change.
In this project, SIOEN develops and fabricates coated textiles into a reinforced panel that is placed underwater. High-precision welding and fabrication create an airtight, inflatable structure capable of withstanding the surrounding pressure.
Results:
- 10 to 35 dB noise reduction (Greenov)
- And less sediment turbidity at the same time
This is significant: such a reduction drastically decreases the acoustic energy reaching animals.
Importantly, the system is reusable, modular, and lightweight — properties typical of technical textiles.
Why Textiles Are Ideal Here
Textile technology offers unique advantages that traditional offshore constructions do not:
- Flexibility
Can be applied around complex structures. - Air Chambers and Porosity
Perfect for creating acoustic damping. - Lightweight
No heavy cranes or foundations required. - Modular and Repairable
Reusable and easy to transport.
In effect, such a system acts underwater like a sound-absorbing wall panel in a concert hall — but at sea.
Other Solutions (and Their Limitations)
1. Bubble Curtains
The classic: a ring of rising air bubbles around the pile.
They work, but:
They work, but:
- Energy-intensive
- Sensitive to currents
- Expensive compressors
They can provide up to about 11 dB additional noise reduction depending on configuration.. (arXiv)
2. Turbine Adjustments
Researchers are also exploring reducing noise during operation, e.g., by adjusting blade pitch control. This can reduce a few decibels without significant energy loss.
3. Temporary Construction Measures
- Soft-start pile driving (gradually increasing strike power)
- Deterrent sounds to make animals leave beforehand
- Scheduling outside migration and spawning seasons
Reduces risk but does not eliminate noise.
4. Acoustic Metamaterials
New developments place special structures on the mast that block vibrations before they reach the water. (Greenov)
Again, these are essentially material and structural innovations — closely linked to technical textiles.
The Unexpected Role of the Textile Industry
What is remarkable is that offshore wind energy is no longer just a domain of steel, shipbuilding, and concrete — it is also textile engineering.
Technical textiles can:
- Absorb sound
- Reduce sediment disturbance
- Protect habitats
- Make installations more sustainable
In the future, we can even imagine wind farms being equipped with permanent “underwater acoustic cladding.”
Conclusion
Offshore wind farms are essential for a climate-neutral future.
But their construction generates intense underwater noise that can disturb or harm fish, larvae, and marine mammals.
Research by Haelters, Debusschere, and Botteldooren clearly shows that pile driving has a critical impact on marine fauna.
The interesting twist?
The solution lies not only in marine biology or offshore engineering — but also in material technology and textile innovation.
With membranes, air chambers, and acoustic structures, textiles can literally form a protective layer between industry and ecosystems.
The energy transition at sea will therefore run not only on wind…
but also on fibers.
