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Floating offshore wind: what future?

26 September 2022
Article by Diogo Neves, responsible for business development in the area of Technologies for the Sea, José Carlos Matos, director of the Wind Energy area, and Miguel Marques, technical manager of the Aerodynamics and Calibration Laboratory at INEGI

Offshore wind energy is today a promising solution to decarbonize our energy system. It generates «clean» renewable energy from an inexhaustible resource1, and thanks to a significant level of technological maturity, it is not only a bet for the future but is already part of our present.

INEGI has been contributing to the acceleration of growth in the offshore wind sector since the first studies, carried out in the mid-2000s. The assessment of the energy potential of the offshore wind resource and the definition of temporal patterns for the placement of offshore wind power in the national electricity grid, were some of the contributions.

Two decades later, in the European geographic space, the maritime space is already seen as a complementary vector to the expansion of wind energy. The North Sea currently represents 70% of the world's offshore wind capacity3, and in Europe the trend is for full growth, with forecasts of reaching the target of 79 to 92 GW of installed capacity in 2030 18.

In fact, in 2020 and 2021, of the new wind power installed in Europe, about 20% was offshore 17, 18, taking advantage of the high availability of wind resources, the low visual and sound impact and the low transmission and distribution losses.

INEGI has therefore been seeking to meet the current challenges of the sector, in collaboration with operators, developers, investors and other entities, especially in the analysis of the structural behavior of the large structural components in operation under real offshore conditions.

Advances in technology open doors to new offshore installations

In the national context, the high depths along the Portuguese coast make it impossible to install wind farms using fixed wind towers on the seabed, as is the case in the North Sea.

However, the need to install offshore wind farms at great depths boosted projects that made it possible to install floating wind turbines (FOWTs)6 at great depths. It is therefore accepted that the massification of offshore wind in Portugal is a plausible scenario, with the launch of tenders for the installation of floating wind turbines on the Portuguese coast as early as 202319.

In fact, the largest share of the wind resource is located in deep-water areas, so the offshore wind industry has been making a strong commitment to the FOWTs field. The investment in the technological development of the floating structure represents a large part of the investment (about 36% of the total cost of a floating turbine), however, this value is expected to decrease dramatically in the coming years with the industrialization of the technology. Even more, considering that these imply lower costs in terms of installation and geophysical and geotechnical studies of the marine subsoil4.

There are 3 major groups of floating wind turbines (FOWT's or floating offshore wind turbines): (i) Semi-submersible; (ii) Spar Buoy; and (iii) TLP – Tension Leg Platform.

The costs associated with the installation and transport of the last two are in fact quite high when compared to floating structures of the semi-submersible type. These, on the contrary, allow the use of a generic wind turbine tug system, already assembled, to the desired installation location, installation at low depths, transport of the complete structure for decommissioning and maintenance of the system in shipyards located in the areas port.

Innovation drives industry growth and better solutions

Everything points to the fact that offshore wind energy is essential to reach the target of 32% of energy from renewable sources by 2030 throughout the European Union, and that it will play an important role in the energy mix of tomorrow. For this reason, we also work on research, innovation and technology transfer.

In this field, INEGI has been working to solve problems associated with corrosion and fatigue of structures, which in the ocean are subject to an extremely aggressive environment. Within the scope of European projects, the work in the area of ​​advanced materials stands out, with the study of the use of materials based on fiber-reinforced polymers (FRP)13, and inspection, with the development of systems to assess the structural integrity and predict the structural behavior of underwater foundations and wind turbines14.

There is clearly a challenging and promising future for the development of offshore renewable energy, namely for offshore wind. Going further, especially in Portugal, requires the concerted involvement of R&D institutions, industry, society and decision-making centres.

Related Pages

Consulting |  Wind Energy


[1] - Xiaoni Wu, Yu Hu, Ye Li, Jian Yang, Lei Duan, Tongguang Wang, Thomas Adcock, Zhiyu Jiang, Zhen Gao, Zhiliang Lin, Alistair Borthwick, Shijun Liao (2019). "Foundations of offshore wind turbines: A review” - Renewable and Sustainable Energy Reviews. Volume 104, 379-393. ISSN 1364-0321,
[2] - Zhengru Ren, Amrit Shankar Verma, Ye Li, Julie J.E. Teuwen, Zhiyu Jiang (2021). "Offshore wind turbine operations and maintenance: A state-of-the-art review” - Renewable and Sustainable Energy Reviews, Volume 144, 110886, ISSN 1364-0321,
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[8] - Skaare, B. (2017) "Development of the Hywind Concept." Proceedings of the ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. Volume 9: Offshore Geotechnics; Torgeir Moan Honoring Symposium. Trondheim, Norway. June 25–30, 2017. V009T12A050. ASME.
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