Reducing cost and risk in floating offshore wind asset integrity monitoring

Offshore windfarm projects currently in development present unique business challenges, even for experienced developers and operators. Newer sites are increasingly

1. far from shore, in harsher metocean conditions,
2. spread over large areas, and
3. utilising floating structures.

Floating turbines, which use mooring line systems to connect to anchors, exhibit the greatest challenges. The lines are vulnerable to corrosion and/or fatigue, leading to failures. Given the increasing complexity and scale, and slim operating margins, floating offshore windfarms will benefit most from cost-effective mooring monitoring systems that minimise inspection burdens and operational costs. While direct mooring load measurements are typically preferred, such systems frequently fail, are non-serviceable and cannot be guaranteed for the life of the windfarm.

In addition, the higher capital expenditure involved in floating projects makes life extension business cases more finely balanced, making the structural health data collection all the more important.

BMT are experts in understanding the marine environment, the excitation forces on offshore structures, and their structural response. Our specialists have developed a broad toolset for asset operators to automate real-time data acquisition, quality control and decision support for O&M strategic planning, failure prediction and maintenance planning for extreme offshore environments.

We have used our decades of offshore energy experience to conceive a robust and cost-effective Mooring Condition Monitoring System (MCMS) for floating wind. The MCMS is designed to monitor mooring line loads in near real-time and inform risk-based inspections that minimise time offshore, driving down risks and costs.

The system consists of reliable primary sensors – including redundant Differential Global Positioning System (DGPS) units, tri-axial accelerometers, and angular rate sensors. These sensors have the advantage of being proven, relatively low-cost and easily accessible for servicing. Plus, they don’t interfere with the mooring system’s operation.

The measurements from the MCMS sensors are accessed and post-processed through an analytics platform, BMT DEEP, harnessing the benefits of Digital Twin technology, and bringing in data from all sources into a common time reference. The resultant data is quality controlled by BMT’s experienced analysts and algorithms developed in-house and fed to a mooring solver engine. The engine generates a time history of each components’ tension loads from motions at termination points. The result is a view of cyclic-load severity, for evaluating fatigue damage accumulation, remaining life and comparing as-measured with predicted fatigue damage rates.

The resultant business insights can be securely accessed from insights dashboards via the BMT DEEP cloud platform. This is designed in-house, with the client always maintaining ownership of the data.

BMT’s innovation is illustrated further in a paper co-authored by BMT’s expert Dr Suvabrata Das. The paper was awarded the jury’s first prize among the 53 offshore technology papers presented at the OMAE® 2024 conference of ASME (American Society of Mechanical Engineers). Access the full paper to further understand how this innovation can help to overcome the business challenges facing floating offshore windfarm projects.

Note: The opinions, beliefs, and viewpoints expressed in this article do not necessarily reflect the opinions of offshoreWIND.biz