IDEA: Integrated Design of Floating Wind Arrays

Objectives

Large arrays of floating wind turbines face challenges related to the sizing and reliability of components, layout of the array, supply chain and logistical demands, environmental and ocean co-user impacts, system-level risk mitigation, and more. The interconnected nature of these challenges makes an integrative floating array design approach essential.

The IEA Wind TCP Task 49, Integrated Design of Floating Wind Arrays, develops information and best practices to facilitate more holistic design approaches for floating wind farms. It has four work packages (Figure 1) with the following objectives:

• WP1: Curate a set of site conditions representative of the global floating wind pipeline. These open-source site condition datasets will fill a frequent data gap and accelerate floating wind research projects by reducing the often-repeated effort of gathering and processing site condition data at the start of each project.
• WP2: Develop reference array designs for typical technology types and select reference site conditions (from WP1). These reference designs build on existing turbine and floating platform reference designs to provide the site-specific mooring system, power cable, and array layout designs needed for array-level research and development uses.
• WP3: Catalogue array-level failure risks, consequences, and mitigation strategies for floating wind arrays, considering and informing the reference design development in WP2. Shedding light on the unique failure modes that arise with floating wind arrays will help de-risk the technology and point to key next steps for risk analysis and mitigation.
• WP4: Survey international trends and identify research needs and innovation opportunities. Consultations with experts and representatives across participating countries will illuminate key innovation opportunities, research needs, and industry challenges to contextualise WP1–3 efforts and inform future research and development prioritisation.

Participation

Task 49 membership includes 12 countries and 78 organisations, including a share of industry participants, some of whom have had strong involvement in meetings and discussions. Table 1 lists the countries and organisations participating.

Progress, Results, and Impact in 2025

In 2025, Task 49 progress centred on completion of reference array designs, the floating array failure risk evaluation report, and consultation reports on the supply chain and overall industry status in participating countries. Two in-person meetings were held, and several brainstorming sessions solidified ideas for a second phase of the task.

Work Package 2 performed final steps to produce four floating wind array designs, each using the IEA Wind 15-MW Reference Turbine developed in IEA Wind Task 37 and most using the accompanying VolturnUS-S semisubmersible floating platform. Cost models were also set up so that each design will include the corresponding cost information.

• The shallow-water case, led by Chern Fong Lee and Muk Chen Ong from the University of Stavanger, has a 60-m water depth and features semi-taut mooring lines and lazy-wave dynamic cables specially designed for the challenge of shallow-water conditions.
• The intermediate-depth case, led by Chris Wright from Venterra Group, has a 300-m water depth and features catenary mooring systems and lazy-wave dynamic cables.
• The deep-water case (Figure 2), led by Ericka Lozon from the National Laboratory of the Rockies, has an 800-m water depth and features taut mooring systems and fully suspended dynamic power cables between turbines.
• A variation of the deep-water case, led by Michel Castagne from IFP Energies Nouvelles, uses a new tension-leg platform design, providing a point of comparison and demonstrating how the reference designs can serve as starting points for new array designs.

Work Package 3, led by Mitra Kamidelivand of UCC and Busra Yildirim of DTU, completed work characterising array-level failure risks.

• The team completed and published the report Failure Risk Evaluation of Floating Offshore Wind Turbines with Farm-Level Implications [1]. This comprehensive report includes a general failure modes and effects analysis (FMEA) for floating wind arrays, a systematic identification and prioritisation of array-level risks, a survey of relevant failure rates, and recommendations for a probabilistic risk analysis framework to assess risks for specific scenarios.
• The report and FMEA tables enable the important next step of exploring failure mitigation strategies for the highest-priority failure pathways. It also contributes to building confidence among stakeholders, investors, and insurers by increasing understanding of potential risks so that they can be better accounted for in design decisions, operational strategies, and maintenance planning.

Work Package 4, led by Ota Dvorak of Venterra Group, completed work surveying offshore wind experts across participating countries and synthesising findings on national supply chains, the state of the offshore wind industry, and future research priorities. These findings were published through two reports:

• The Supply Chain Capability Consultation Report [2] builds on consultations with representatives from each participating country to provide insights into actions to develop domestic offshore wind industries, how supply chain capacities align with national targets, plans for sourcing raw materials, and workforce readiness.
• The Update on the Development of the Industry in Participating Countries report [3] surveys the overall floating wind industry status in different countries and reflects on stakeholder interaction throughout the task to recommend future research on the links between policy and technology and the role of regulatory frameworks to develop new and existing markets.

Next Steps

In the first half of 2026, Task 49 is focused on publishing the final deliverables — the four reference array designs and the failure risk mitigation report — and preparing a task extension proposal to launch a second phase of the task. The original December 2025 end date was postponed so that a solution could be found to new U.S. restrictions on leading an extension proposal. This additional time also allows for developing a more refined plan and more robust contributor list when proposing the next phase.

The second phase of Task 49 is planned to build on the current phase's accomplishments with increased emphasis on array-level loads analysis, design standardisation across varying site conditions, and coupling operations and maintenance analysis with up-front design decision-making to enable more holistic design approaches for floating wind arrays.

References

1. Yildirim, B., Kamidelivand, M., Nasr, C., Persent, E., Slack, E., Schlanbusch, R., Jiang, Z., Kolios, A. (2025). Failure Risk Evaluation of Floating Offshore Wind Turbines with Farm-Level Implications. IEA Wind Task 49. https://iea-wind.org/wp-content/uploads/2025/10/IEA_Wind_Task49_WP3_Failure_Risk_Evaluation.pdf
2. Dvorak, O., Bohan, G., Blomgren, A., O'Connell, R., and Jiang, Z. (2025). Supply Chain Capability Consultation Report. IEA Wind Task 49. DOI: 10.5281/zenodo.19707443.
3. Dvorak, O. and Bohan, G. (2025). Update on the development of the industry in participating countries. IEA Wind Task 49. DOI: 10.5281/zenodo.19707539.