Discover how floating wind is revolutionizing offshore renewable energy production with innovative technologies, advanced anchoring and deep-sea potential

by Orizio Luca

In recent years, the renewable energy sector has seen rapid growth in wind installations, both onshore and offshore . However, while traditional offshore wind farms have been installed mainly in shallow waters, often less than 60 metres deep, the demand for new sites and the scarcity of available land near the coast have pushed the industry to explore innovative solutions for deeper waters. This is where floating wind comes in , a rapidly evolving technology that can open up new horizons for energy production in the open sea, where the wind is stronger, more constant and the space virtually unlimited.

But what is floating wind energy really? How do floating platforms work and what are the technical challenges related to anchoring? What are the prospects for this technology in terms of energy potential and environmental impact? This article aims to provide an in-depth technical overview of the state of the art of floating wind energy, analyzing the main technologies available today, the anchoring systems and the enormous potential offered by deep offshore waters.

Floating Wind: Principles, Differences and Motivations

Floating wind represents an engineering solution designed to install wind turbines on floating platforms anchored to the seabed, as opposed to the more common “fixed-bottom” plants, where the towers are fixed to structures resting directly on the seabed. This design difference allows floating plants to be placed in much deeper waters, generally between 60 and 1000 meters, overcoming the technical and economic limits of traditional foundations.

The use of floating wind energy arises from the need to exploit marine areas further from the coast, where the power and consistency of the wind are greater, but the seabed quickly becomes too deep for conventional systems. For example, in the seas of Northern Europe, Japan, the west coast of the United States and, more recently, in the Mediterranean and in some areas of the Atlantic, the availability of deep seabeds and the need for decarbonization have accelerated interest in floating wind.

This technology promises to significantly reduce the levelized cost of energy (LCOE), increase the competitiveness of wind energy compared to fossil fuels and enable the industrial production of green hydrogen offshore, thanks to direct integration with electrolysis systems.

The main technologies of floating platforms

The heart of floating wind energy is represented by floating platforms that support turbines. In recent years, three main types of platforms have emerged, each with specific technical and application characteristics.

Spar-Buoy (or floating pole platforms)

Spar technology is based on a long hollow cylinder, ballasted at the bottom, which gives stability to the structure by exploiting the principle of the low center of gravity. The platform is partially immersed (even for tens of meters), allowing excellent resistance to wave motion and a limited vertical excursion of the turbine. However, the large draft makes these platforms suitable only for sites with very deep seabeds and with the possibility of assembly in suitable port basins. The best known example of this technology is Equinor's Hywind, installed in Scotland.

Semi-submersible (semi-submersible)

Semi-submersible platforms are made up of multiple floating elements, arranged in a triangular or square geometry, connected to each other by means of lattice structures and ballasted in a distributed manner. This solution offers good stability even in the presence of waves and allows assembly and deployment in ports with limited depths. They are currently the most widespread type in pilot and commercial projects, as demonstrated by the WindFloat project in Portugal.

Tension Leg Platform (TLP)

TLPs use vertically tensioned cables (tension legs) anchored to the seabed, which keep the platform in position and minimize vertical movements due to wave motion. Thanks to the permanent tension of the cables, these platforms are very stable and can accommodate large-scale turbines. However, the engineering complexity of the anchors currently limits their commercial deployment, although they are promising for very windy sites and at great depths.

In addition to these solutions, research is developing hybrid variants and experimental models, often adapting technologies already used in the offshore oil & gas industry, with the aim of reducing costs, simplifying assembly and improving resistance to the extreme conditions of the open sea.

Anchoring Systems and Cables: An Engineering Challenge

One of the most critical technical aspects of floating wind power is represented by the anchoring systems. Floating platforms must be firmly fixed to the seabed to resist winds, waves, currents and storm surges, but also “flexible” enough to absorb the movements induced by marine dynamics, avoiding excessive stress on the turbine and the structure itself.

The main anchoring systems used are:

- Chains and catenary cables: the simplest system, which uses the weight of the chain/cable and its curved shape (catenary) to absorb horizontal forces. It is suitable for soft and deep seabeds, but requires large buffer areas around the platform.

- Taut leg: the cables are stretched between the platform and the seabed with the help of anchors or driven poles. They allow for greater precision in positioning and reduce the footprint on the seabed, but require high-strength materials and complex tensioning systems.

- Suction or propeller anchors: used to fix cables or chains to the seabed, they are chosen based on the geotechnical nature of the site (sand, clay, rock, etc.) and the weather-marine characteristics.

Special attention must also be paid to submarine electrical cables, which are called upon to transport the energy produced by the turbine to the mainland or to an offshore collection station. These must be flexible and resistant, capable of following the movements of the platform without being damaged, and are often equipped with special protection against abrasion, currents and corrosion.

Potential and advantages of floating wind in deep water

Floating wind power overcomes many of the limitations of traditional offshore installations, offering technical, economic and environmental benefits:

- Access to windier and less exploited sites: floating platforms can be placed in areas far from the coast, where winds are stronger and more constant, significantly increasing the average annual output of the turbines.

- Reduction of visual and landscape impact: the distance from the coast allows to minimize the effect on the landscape and interference with tourism, fishing and maritime activities.

- Expanding Installable Potential: Deep waters represent a potentially vast surface. According to some estimates, the Mediterranean alone could host floating plants capable of generating over 500 GW of power, a figure greater than the electricity needs of several European countries.

- Innovation and creation of industrial supply chains: the birth of a new industry around floating platforms can generate economic development, innovation and jobs, especially in the naval, engineering and manufacturing sectors.

The benefits are not limited to energy production. Floating wind can facilitate the decarbonization of offshore industrial sectors (oil, gas, mining), enable the production of green hydrogen directly at sea and, in the future, integrate with storage systems and smart grids.

Critical issues and technological challenges

Despite its great potential, floating wind still faces significant challenges before becoming a mainstream technology:

- Investment costs still high: although rapidly decreasing, the costs of platforms, anchors and cables remain higher than those of fixed installations.

- Reliability and durability of materials: the marine environment, especially in deep waters, is extremely corrosive and subject to extreme weather events. Constant innovation in materials and maintenance systems is required.

- Maintenance and accessibility management: Operating on floating platforms far from the coast brings new logistical challenges, from remote surveillance to repair techniques using drones and underwater robots.

- Environmental impact to be carefully assessed: interactions between anchoring systems and benthic ecosystems must be monitored, as well as the effects on marine mammals and bird migration routes.

Another crucial point concerns regulatory standardization and authorizations, which today vary greatly from country to country and are often poorly suited to this new technology.

State of the art and international case studies

Today, several pilot and pre-commercial floating wind farms are in operation, mainly in Europe and Asia. Some of the main case studies include:

Hywind Scotland (UK): the world's first commercial floating wind farm, with 30 MW of installed capacity, based on spar-buoy technology.

WindFloat Atlantic (Portugal): semi-submersible platforms with 8.4 MW turbines each, which have demonstrated the reliability of the technology even in adverse weather and sea conditions.

Kincardine (Scotland): one of the largest floating parks, with a capacity of 50 MW and semi-submersible platforms.

Projects in Japan, South Korea and the United States: where the high depth of the seabed near the coast often makes floating the only viable option.

The Mediterranean is also approaching this technology, with pilot projects in Italy, Spain and France. Italy, in particular, is promoting several initiatives between the Adriatic, Tyrrhenian and Sicilian Channel, involving major energy players and local industrial companies.

Future Prospects: Towards an Offshore Energy Revolution

The medium and long-term scenarios for floating wind are extremely promising. According to the IEA (International Energy Agency), the global technical potential of floating wind exceeds 10,000 GW, enough to cover several times the current global electricity demand. The exponential growth of installations, supported by cost reductions and continuous innovation, could lead this technology to represent a significant share of the energy mix of many coastal countries.

Competitiveness with fossil fuels and traditional wind will depend on the industry's ability to standardize platforms, automate assembly, and improve the efficiency of anchoring and transmission systems. Equally important will be the development of suitable industrial ports, local production chains, and partnerships between energy and naval companies and innovative startups.

Another frontier is represented by the synergy between floating wind and other marine technologies, such as floating solar, offshore hydrogen production and underwater energy storage systems, to create true self-sufficient and resilient “energy islands”.

Conclusion: the role of floating wind in the ecological transition

Floating wind represents one of the most fascinating technological challenges of the energy transition, capable of revolutionizing the production of renewable energy in deep waters around the world. Its potential is immense, as are the opportunities for industrial development, innovation and creation of new jobs.

For this technology to become a protagonist in the global energy landscape, it will be essential to invest in research, experimentation and training of skills, in addition to promoting a stable and transparent regulatory framework. Italy, with its strategic geographical position and a long maritime industrial tradition, can play a leading role in the development of floating wind energy in the Mediterranean.

There is still a long way to go, but the winds of innovation are blowing ever stronger towards the future of clean energy in the open sea.

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