Ailes Marine, the developer of the Saint-Brieuc offshore windfarm in France, says a loose hydraulic connection on a drilling template caused the leak which led to 170 litres of hydrualic fluid entering the environment
The incident took place while Van Oord’s jack-up vessel Aeolus was conducting drilling operations for the pin piles for the foundations for the windfarm.
Ailes Marine confirmed the vessel has now departed the Saint-Brieuc project for Vlissingen in the Netherlands. The developer said other work, including preparation for the inter-array cables to be installed by Prysmian continues, using the vessel Aethra.
Ailes Marine said the incident took place during the second phase of drilling since the start of the work on 3 May 2021. It said a safety system on the template detected a sudden leak of hydraulic fluid. Drilling activity was immediately halted, and a remotely operated vehicle used to identify the source.
“Once the location of the leak was identified, inspection confirmed it was not possible to repair it without reassembling the drilling template on Aeolus,” said Ailes Marine. “It was therefore necessary to initiate its recovery.
“This extremely sensitive template recovery phase, which took 24 hours, was carried out with assistance from two support vessels, Kermor and REM Trader. Their role was to identify any potential contamination during the lifting phase and avoid a larger incident.”
The developer said investigation by the judicial police and the maritime gendarmerie into the incident is ongoing. Ailes Marines confirmed the source of the leak is not structural damage to the template, but a hydraulic connection that loosened during the work.
The company confirmed the incident resulted in the release of Panolin HLP Synth hydraulic fluid into the marine environment. The hydraulic fluid is classified as ‘readily biodegradable.’
Overflights by aircraft of the site subsequently confirmed that fluid on the surface that was clearly visible beforehand had totally disappeared.
On 15 June 2021, a representative of Ailes Marines met with France’s Minister of Ecological Transition, Barbara Pompili, to explain what had happened.