A specialist offshore risk consultancy is warning the wind industry that unexploded ordnance (UXO) can present a hazard throughout the life of an offshore wind farm.
6 Alpha Associates says that surveys for UXO are typically carried out prior to the construction of offshore wind farms but data from surveys is not always handed over to operators and maintenance contractors undertaking the operational phase of a project.
This means that UXO remains a danger to infrastructure and personnel, especially as wave and tidal processes, and sometimes human activities such as fishing, can move UXO devices around on the sea bed.
"Unfortunately, while the UXO risk threat is commonly well managed and monitored throughout the development phase, it is our experience that some project construction teams are failing to handover and share key UXO information to inbound operations and maintenance teams," said Simon Cooke, Managing Director, 6 Alpha Associates.
"Despite an excellent approach to continuous learning, health and safety and cost reduction in the construction phase, as projects become operational and the personnel teams change, there is a risk of failure to pass on some of the most important risk management data."
According to 6 Alpha, specialist surveys carried out to detect UXO in a project's development phase will not investigate every anomaly due to the cost. Therefore only anomalies that resemble UXO and which are in the way of installation operations are investigated.
This method enables developers to install offshore wind structures safely and at best value for money, but can leave UXO signatures on site. "Once development teams have often reduced the UXO risk to as low as reasonably practicable (ALARP), the issue is widely regarded as having been dealt with for the remainder of the project lifecycle," said Cooke. "Of course, with the tendency of some types of UXO to move around the seabed, this certainly isn't the case, and project managers should ensure that UXO risks are not only registered and mitigated through out the O&M phases of work but also that their assets remain clear of UXO in order to reduce the risks to personnel on site and to avoid expensive delays and down-time."
Techniques for identifying and mapping UXO munitions is becoming increasingly sophisticated and it is now possible to plot the approximate UXO drift direction and distance likely to be travelled over time, says 6 Alpha. Such techniques not only enhances the longevity of UXO safety sign-off certificates, but also enables operations and management teams to better understand and quantify the true scale and costs associated with managing long-term offshore UXO risks.
Sian Crampsie
Linkedin
