Mooring systems for Marine Renewables, and more specifically floating wind turbines, significantly differs from existing oil and gas systems (due to water depth, highly dynamic floater motion, requirements to reduce the footprint). Hence, standard rules and design tools need to be modified and validated. In addition, the envisaged technical solutions (configurations, material, mutualisation of anchors) increase uncertainty with regards to the life span prediction.
The consequences associated with a mooring line failure can represent a significant risk for marine stakeholders, as wind farms will be deployed in high activity density areas. The feedback on system health monitoring for mooring system is scarce, leaving remaining challenges, including the reliability of line load measurement in extreme conditions for instance. Following the recorded incident in the oil and gas industry, the use of surveys significantly increased, even though it only provide an observation for a given period without any mean of extrapolation for predictive maintenance.
Scientific advances and innovation
Therefore, Advanced Mooring Monitoring appears as a strategic challenge for floating marine renewables. The main objective for this project are:
- Develop a monitoring methodology to assess the life span of mooring line components based on in-situ measurements (tension, angles, floater motion, environmental data) together with existing numerical tools. This methodology will enable a periodical assessment of the remaining life span for each component and therefore enable predictive maintenance planning.
- Develop specific warning tools in order to prevent drifting risks and avoid the associated consequences for marine renewable industry.
- Improve or strengthen the existing methods for extreme response prediction used in the conception and design phases. This could lead to safety coefficient reduction proposals.
Expected technical and economic impact
AMM-EMR project will identify the main barriers regarding mooring monitoring for floating marine renewables, and more specifically in the field of floating offshore wind.
Indeed, French floating wind pilot farm are under development. In order to ensure reliable and sustainable farm operations, it will be necessary to verify each component of the mooring system with regard to the initial desin life calculated.
AMM-EMR objectives is to go further than decreasing the technical risks and to secure the production of floating MRE, with a decrease the OPEX with optimized anticipated maintenance.
Key project milestones
- January 2018 - Project start
- Decembre 2018 - Identification of key parameters for monitoring
- Decembre 2019 - First validation of the overall methods with numerical data inputs.
- Decembre 2020 - Validation of the methodology based on open sea testing data.
Tools and indicators for in situ life span assessment
PhD work will break down the barriers, although additional validation stage might be required. These research will most likely have to be extended.