Developers, utilities and asset owners are failing to take account of the risks posed by munitions moving from their recorded positions during the operations and maintenance phases of their projects. That is according to specialist offshore risk consultancy, 6 Alpha Associates.
Prior to installation work, where there is a high risk of encountering unexploded ordnance (UXO), it is common to undertake a specialist geophysical survey to detect it. Unfortunately, the seabed is often littered with debris, much of which can be confused with UXO. The costs of investigating each and every geophysical survey anomaly that resembles UXO (some of which might be, but the vast majority of which will not), is prohibitively expensive. Therefore, only those anomalies that resemble UXO and that are in the way of installation operations are usually investigated (typically by diver or ROV) and if they are proven to be UXO they are subsequently rendered safe.
Whilst such practices enable the installation of infrastructure in safety and at best value for money, inevitably a significant number of anomalies with known UXO signatures (but which have not been verified as such through investigation) remain on site, often within engineering working space and sometimes in quite close proximity of installed infrastructure. Not only should such known anomalies be avoided throughout the O&M period, but over time, as a direct result of wave and tidal processes, and in some cases human activities (eg fishing), such items may continue to shift on the seabed, causing them to move to within dangerous proximity of offshore wind turbine or platform foundations and cables, that may themselves be the subject of on-going Operations and Maintenance (O&M) activities.
In the short term this presents a demonstrable risk to the safety of personnel, vessels and the installed infrastructure that is in close proximity of such prospective hazards, while in the medium to long term, verification of such anomalies as UXO can lead at best to expensive operational downtime and the possibility of long delays, and at worst to an accident.
“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,”
“This is certainly the case in our specialist area of expertise, offshore UXO risk management, where 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. 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.”
Through the use of specialist geophysical survey techniques, enhanced UXO munitions mapping and appropriately applied UXO risk management procedures, it is increasingly possible to accurately plot the approximate UXO drift direction and distance likely to be travelled with time, typically on a per annum basis. This specialist work, which has been successfully undertaken by 6 Alpha Associates for a number of developer clients, 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.
To date, development cycles have enabled offshore wind farm construction teams to better understand the first three years of a typical 25-year project. As the focus for offshore wind moves towards cutting the cost of electricity generation, enhancing the understanding of Munitions Migration is imperative for future project success.