Ocean Winds, a joint venture between EDP Renewables and ENGIE, has published a report on environmentally safe and predictable UXO disposal at its Moray West offshore wind farm.
The report demonstrates how the “low-order deflagration” method for disposal of unexploded ordnance (UXO) creates predictable low levels of underwater noise in the marine environment.
UXO seabed surveys and disposal are standard on offshore infrastructure projects, including offshore wind projects. The report has been compiled following the first large scale use of the method during UXO clearance prior to offshore construction of Moray West, an offshore wind farm in the outer Moray Firth, Scotland, developed by Ocean Winds.
All 82 UXOs identified for disposal were safely disposed of using this technique with the works undertaken by EODEX, a Scottish based innovator bringing this technique to the sector in partnership with Ocean Winds, according to the company.
As reported by lead author Nuria Abad Oliva, Offshore Consents Manager for the project, the technique had previously only been used for military purposes. This was the first successful use of the technique to support offshore renewable developments, with underwater noise measurements made by Seiche Ltd during disposal operations.
Mines, bombs, torpedoes and naval shells with explosive content varying in size from 6 to 700 kgs were successfully neutralized. Underwater noise was limited to the small disposal tool charge, avoiding large underwater explosions from traditional UXO disposal techniques.
The report identifies a key advantage of the technique as being the accuracy of underwater noise modelling and impact assessment compared to less certain and potentially large estimates of noise from traditional disposal techniques. Traditional techniques can cause significant environmental damage and harm marine mammals.
By publishing the outcomes of this study, Ocean Winds hopes that regulators and the offshore wind sector will benefit from these findings about the environmental benefits of low-order deflagration.
“The challenge of disposal of over 80 UXOs using traditional techniques was daunting. Working with EODEX to deploy low-order deflagration for the first time on an offshore wind farm has been fantastic achievement. The disposal resulted in negligible underwater noise and ensured the protection of the prized marine mammal populations in the waters around the project.
“We hope this report will lead to informed guidance from regulators and appropriate adoption of the technique by developers where environmental sensitivities indicate it would be a useful tool,” said Catarina Rei, Head of Permitting and Environment for Ocean Winds.