Blowing Bubbles

MARINE LIFE PROTECTED FROM NOISY WIND FARM CONSTRUCTION

As European countries aim to make the North Sea into the world's 'largest green energy power plant' and more and more offshore wind farms are being erected around the world, the lives within our oceans are being affected.

The deafening thud of 'pile-driving' - where the steel foundation that supports a wind turbine is hammered into the seabed - can normally be heard for miles, exaggerated by the acoustics of the ocean, which can be catastrophic for marine life. Shipping all the parts around also creates noise, and before they start construction, often the sea has to be cleared with controlled explosions of munitions dumped after World War Two. Sea mammals can suffer from displacement and permanent hearing loss, which since they rely on echolocation to communicate and navigate, can lead to their death.

However, 'big bubble curtain' technology (deployed initially as compressed air barriers to limit oil spills) has come to the rescue over the past decade, in the form of large perforated hoses, laid on the seabed, through which air is pumped to help break up the sound waves. The technology, pioneered by a German engineering company, Hydrotechnik Lubek, with funding from Germany's environment ministry muffles the noise to a threshold deemed safe by scientists with harbour porpoises in mind.

In the North Sea, the number of wind turbines has risen from only 80 in 2002, to more than 4,000 today - and many more are planned as part of the green energy revolution. There are efforts to make construction less noisy in the first place, by using floating turbines for example, or securing the foundations through suction but this only works if the type of sea floor, and water depth, permit.

In Europe, data from about a decade of use, suggests that the bubble curtains are remarkably effective. "Almost all major wind farm operators utilise this (bubble) technology," said Hydrotecknik's, Jorn-Philip Pfeiffer "particularly in Europe where there is a race to construct additional offshore wind farms as part of their collective endeavours to reduce CO2 emissions and combat global warming." Hydrotechnik Lubek has also recently partnered with a company to deploy the bubbles in the first large-scale offshore wind farm in the US, off the coast of Massachusetts.

Instead of it being 'curtains' for wildlife, hopefully these bubbles will always be celebratory ...

(Air Bubble Technology Diagram credit: Hydrotechnik Lubek)