CompoSmart

WHY

Offshore structures for renewable energy, such as wind farms, typically have a lifespan of no more than 25 years, as welded joints are prone to cracking due to constant exposure to wind and wave forces. Frequent inspections of these welds drive up maintenance costs. With the growing demand for renewable energy, substantial investments will be needed every 25 years to build offshore infrastructure, leading to environmental disruption, depletion of raw materials, and increased CO₂ emissions.

A promising solution is currently under development: a new connection technology using composite joints for foundations (WrapNode-I and WrapNode-II), which could replace traditional welded joints. This innovative approach offers a significantly extended lifespan, lasting up to 5,000 times longer (Pavlovic et al., 2024). The incorporation of fibre optics enables real-time structure health monitoring, facilitating predictive maintenance and reuse of foundations.

However, key questions remain unanswered, such as how accurately the data from fibre optics reflects the actual condition of the joints and whether other limitations might affect the lifespan extension of foundations. This project addresses these uncertainties, laying the groundwork for an offshore pilot as part of the forthcoming WrapUp project, in which the composite joints will be demonstrated offshore.

This project will help achieve two key goals:

1. Promoting circularity: By understanding the condition of the joints, the foundations can be used longer or reused for multiple generations of offshore wind farms.
2. Reducing maintenance costs: Fewer hours will be needed for inspections because real-time monitoring will be possible.

Additionally, this system could be used for foundations for other offshore renewable energy sources, such as floating wind and solar farms.

WHAT

This ambitious project is focused on developing next-generation composite joints for offshore wind foundations, designed to last over 100 years. We will validate the application of fibre optics lifetime monitoring in innovative composite joints to enable targeted maintenance, extend the lifespan and assess reuse potential of jacket foundations for offshore wind turbines. Working closely with operators, fabricators and material suppliers to meet specific design requirements, we will develop a robust design and manufacturing process for seamlessly integrating fibre optics into the joints.

As part of the validation process, we will design, build, and test two lab-scale prototypes. We will use the test results to enhance existing numerical models, evolving them into digital twins. Powered by real-time fibre optic data, this digital twin will continuously monitor the prototypes and predict their lifespan. An expert review will be conducted to evaluate the performance of both the monitoring system and the digital twin model.

Building on this progress, we will develop a predictive maintenance strategy informed by real-time data and assess the feasibility of reusing existing foundations. Finally, a long-term cost-benefit analysis will be performed to quantify maintenance savings from adopting monitored composite joints and to evaluate the financial viability and potential benefits of foundation reuse.

EXPECTED RESULTS

The project will obtain the following results:

1. Validation of the monitoring system for composite joints
   1. Technical feasibility: The project will validate the technical feasibility of composite joints with integrated fibre optics in the lab by testing two prototypes.
   2. Digital twin: A digital twin will be developed based on existing numerical models and fed by data from the fibre optics. This model will map the structural health of the joints through real-time monitoring.
   3. Predictive maintenance strategy: Using the digital twin, a predictive maintenance strategy will be developed to reduce maintenance costs.
   4. Reuse of foundations: The project will assess the potential for foundation reuse, which could result in significant cost savings and environmental benefits.
2. Evaluation of the business model
   1. Long-term cost-benefit analysis: An assessment of potential savings for an offshore wind farm through the use of the monitoring system.
   2. Benefits of reuse: An evaluation of the benefits of reusing wind farm foundations. This aspect will provide key insights into reuse’s economic feasibility and advantages.

Through this project, we will gain critical insights, including linking data from embedded fibre optic fibres to lifetime consumption estimation via the digital twin model, understanding the requirements from developers and industry experts for extending structural lifespans and identifying potential cost savings enabled by composite joints with integrated monitoring systems.

The knowledge generated will enable Tree Composites and its partners to capitalise on the unique benefits of composite joints, such as a lifespan up to 5,000 times longer than traditional welded joints and the capability for real-time monitoring in future commercial applications. By initiating development now the monitoring system can be deployed in both onshore and offshore pilot projects featuring composite joints, providing real-world validation and performance data.

These advancements are expected to reduce electricity costs by lowering CAPEX and OPEX for offshore wind developers, ultimately supporting an affordable, reliable, and sustainable energy supply for Dutch society.