EcoGBF – Rethinking bottom-fixed foundations for offshore wind

Moving beyond the monopile

Today, most bottom-fixed offshore wind turbines rely on monopiles driven deep into the seabed using heavy hammering. This is a challenging task in hard soils and for seabeds with boulders. Furthermore, the installation often involves high costs, the need for large, specialized vessels, significant underwater noise, and disruption to marine ecosystems. The fabrication and transportation of these long and heavy monopiles also requires specialised tooling and careful planning.

The EcoGBF project investigates a different approach. Instead of penetrating the seabed, the foundation rests directly on the ocean floor, achieving stability through gravity rather than embedment. While conventional gravity‑based foundations have been deployed, typically with massive concrete bases, EcoGBF builds on this principle with a lighter, modular steel design that uses the strength of steel only where needed and relies on readily available ballast materials for stability, offering practical, ecological, and logistical advantages. The concept is analogous to an umbrella stand: a wide-base structure is placed on the seabed and stabilized by adding ballast, such as sand or gravel, in a cylindrical ballast confiner.

This gravity-based concept eliminates the need for pile driving, enabling a quieter, simpler, and potentially more sustainable installation process which is fully recyclable/reusable by the end of the service life.

A multidisciplinary consortium

Running over three years from its start in June 2025, EcoGBF aims to deliver a clear, data-driven answer to a critical question: can EcoGBF as a steel gravity-based foundation offer a viable, scalable alternative to monopile bottom-fixed, jackets and conventional concrete gravity-based foundations for offshore wind?

The results of this project are expected to provide valuable insights into feasibility, cost competitiveness, installation speed, and environmental impact.

The EcoGBF project brings together a specialized group of partners, each contributing critical expertise:

• Subsea Structural Technologies is the inventor of the EcoGBF concept and the consortium lead.
• MULTi.engineering Building & Infrastructure leads the investigation of structural concepts, evaluating different configurations to identify the most suitable design.
• MULTI.engineering Maritime and Offshore focuses on transportation and installation strategies, and the impact of environmental forces on the EcoGBF structure during installation.
• Jan De Nul contributes installation expertise and offshore construction know-how, with specialised knowledge of vessel capabilities and the offshore execution strategy.
• HAEDES evaluates environmental performance, including seabed erosion around the structure and the potential for marine organism growth, ensuring ecological considerations are embedded in the design.
• Iemants, a foundation manufacturer, assesses manufacturability, with particular attention to the challenges of producing and handling a large-diameter, thin-walled steel ballast confiner without deformation.

The project has received funding from VLAIO, the Flemish government agency supporting entrepreneurship and innovation, and is supported by the Blue Cluster, the Flemish innovation cluster for the sustainable blue economy, underlining the strategic importance of developing next-generation offshore wind solutions.

💡Reading tip
Interested in other approaches to offshore wind foundations? MULTI.engineering is also involved in R&D on floating foundation systems, exploring an alternative solution for deeper-water sites where bottom-fixed structures are no longer feasible.

Read more: https://www.bluecluster.be/projects/ecogbf

Image courtesy of Subsea Structural Technologies.