Air Bubbles to Protect North Sea Harbor Porpoises (Germany)
In spite of severe weather conditions in November and December last year, Trianel Borkum wind farm, located 60 kilometers off the East Frisian coast, continues on schedule and within budget. Five months after the start of construction, the jack-up barge Goliath has installed a total of 26 of the 40 foundations into the seabed.
Underwater sound insulation has been for the first time successfully used in Germany. The so-called “big bubble curtain” is used to protect the harbor porpoises that use sound pulses to communicate in the North Sea.
During a joint press conference in Essen, Trianel and Nature Conservation Association (NABU) presented the interim results of the accompanying research prior to noise control.
“For the NABU it is necessary to reduce the impact on threatened and legally protected species to a minimum,” said NABU expert Elmar Große Ruse.
Before the construction began, Trianel discussed the issue of protection of harbor porpoises in the North Sea.
The Managing Director of Trianel wind farm Borkum, Klaus Horstick, explains: “The offshore permits require compliance with a noise standard of 160 decibels at 750 meters distance from the sound source. The sensitivity of this value lies in the fact that there has been no technology available in the market, which ensures the value. The large bubble curtain, we seem to have found a common way to meet the noise control with our partners. “
On the 56 square kilometer area of the wind farm Borkum Trianel, biologists estimate the population at 50-100 porpoise individuals. Each individual animal is strictly protected.
Offshore WIND staff, February 13, 2012; Image: trianel-borkum