Under water, sound travels great distances. How far exactly depends on the noise level and the frequency spectrum of the source, as well as the environmental conditions. But any underwater noise can have harmful impacts on the ecosystem, which is why it’s important to take steps to keep the impact zone around offshore construction sites as small as possible. And that means new opportunities for the drilling techniques of NPM portfolio company Dieseko.
The conventional, modern construction techniques used today for building or dismantling offshore wind farms generally revolve around piledriving. But this method has the disadvantage of producing noise disturbance with every slam of the hammer on the pile – noise that is clearly detrimental to sea life in a wide radius around the site.
But the technique Dieseko uses is different; it generates a constant noise level instead of powerful intermittent impact noise. Dieseko is convinced that the noise level this drilling technique produces is considerably lower than the noise produced by piledriving techniques, and recently had independent assessments conducted to prove it.
Strict German criteria
While dismantling the Lely offshore wind farm, Dieseko invited an independent expert to conduct underwater noise level measurements. The company was hoping to obtain evidence demonstrating whether the noise levels generated by Dieseko’s largest vibratory hammer, the PVE 500M, might keep noise levels below predefined threshold values within a radius of 750m from the source. These threshold values are based on the criteria used in Germany – a country which, thanks to its Energiewende policy (the rapid transition from fossil fuels to sustainable energy), has some of the most forward-looking regulations governing the construction of offshore wind farms.
The results showed that the noise level measured was lower, even much lower, than the permitted threshold values. Looking at the circumstances, similar results should be expected for foundations and the use of vibratory hammers in comparable offshore conditions.
Reduction of underwater noise
Dieseko is proud of the fact that its vibratory hammering technique will soon be able to make an important contribution towards reducing the underwater noise level caused by offshore projects. Beyond this, the company sees the results as proof that its continuing efforts to develop advanced foundation solutions with the minimum possible ecological impact will truly be paying off in the near future.
Dieseko has built up a broad portfolio of extraordinary completed projects, such as the successful dismantling of a number of turbines at Nuon’s Lely offshore wind farm in late 2016.
