285: Offshore floating wind farm


Towards the end of 2019 there were 5,000 offshore wind turbines in 110 parks with a total power output of 22.1 Gigawatts. Fixed to the seabed, these turbines are limited to shallow waters. Yet close to 80% of the world’s offshore wind resource potential is in waters deeper than 60 metres, too deep for the foundations, but where winds are stronger and more consistent.


Floating offshore wind turbines.

In June 2009, Norway’s Statoil (now Equinor) launched Hywind, the world’s first operational deep-water floating large-capacity wind turbine. The 120 metres (390 ft) tall tower with a 2.3 MWh turbine was towed 10 kilometres (6.2 mi) offshore into the Amoy Fjord in 220 metres (720 ft) deep water off Stavanger, Norway for a two-year test run.

In October 2020, Norway-based OIM Wind, together with its financial partners, has signed an EPC contract with the CIMC Yantai Raffles Offshore shipyard in China and its Swedish subsidiary Basstech for the construction of an installation vessel capable of installing giant next-generation XXL offshore wind turbines, including full height towers that reach more than 130 metres.

The vessel, currently referred to as BT-220IU Wind Installation Unit, will enter into service by the end of 2022 and will be operated by Norwegian company OSM Maritime. It is LNG-powered, battery-backed up, and made for 15+ MW wind turbines. It will feature a Huisman heavy lift crane with a lifting capacity of 2,600 tonnes. The crane will have a main hook height of 165 metres above deck and 195 metres above sea level, even at the vessel’s maximum operational water depth of 67 metres.

Following proof that the suction anchor system worked, Equinor and Masdar launched the world’s first floating wind turbine farm, at a depth of 100 metres and situated 29 kilometres (18 mi) off Peterhead, Scotland. The farm has five 6 MW Hywind floating turbines with a total capacity of 30 MW.

Work is now underway for the 88MW Hywind Tampen floating wind farm will comprise 11 Siemens Gamesa 8MW wind turbines supported by the Hywind technology developed by Equinor and expected to come online in late 2022.Once commissioned, the wind farm is projected to cover a third of the total energy needs of two oil and gas platforms, Gullfaks and Snorre, with wind power instead of gas.

Floatgen is the only floating wind turbine in France today. It is situated off the Mediterranean coast of Le Croisic, one of the largest wind resources in Europe, The venture is a joint venture of Ideol, Bouygues Travaux Publics, Centrale Nantes engineering school, RSK Group, Zabala, the University of Stuttgart, and Fraunhofer IWES. The anchorage system, developed by Ideol is a ring-shaped floating foundation based on a central opening system and called a Damping PooAbove this a Vestas V80 turbine is mounted. After two years of trial,  in February 2020, Floatgen produced 9 GWh of electricity

Milan-based Ichnusa Wind Power has applied with the Port Authority of Cagliari for a 30-year concession to build and operate an export cable connection for Sardegna Sud Occidentale a floating wind farm off the west coast of Sardinia. Some 35 kilometres off the coast of the San Pietro island, it will comprise 42 wind turbines measuring 265 meters each, on a sea surface of 49 thousand square meters.

Instead of the conventional three-bladed turbines, the Ichnusa solution uses a single-bladed angled, scalable rotor, able to adjust its angle to the wind currents of up to 70 m/s. The planned capacity is 12 MW each for a total of 504 MW.

In October 2011, Principle Power installed their 2 MW WindFloat turbine 5 kilometers off the Portuguese Atlantic coast where, during the next five years, it encountered 17-metre wave heights and 111km/h winds, but generated 17GWh of electricity.

Based on this, in January 2020, Principle Power is preparing a the world’s first semi-submersible floating wind farm for operation 20km off the coast of Viana do Castelo, Portugal. The wind farm is being developed by the Windplus consortium that includes EDP Renewables (54.4%), Repsol (19.4%), Engie (25%) and Principle Power (1.2%).

The Fukushima floating offshore wind farm demonstration project (Fukushima FORWARD) serves as a symbol of Fukushima’s recovery from the nuclear disaster caused by the earthquake and tsunami in 2011.

The phased development of the project includes the installation of three floating wind turbines and a substation at approximately 23km off the Fukushima coast.

The project is sponsored by Japan’s Ministry of Economy, Trade and Industry (METI).The Fukushima Offshore Wind Consortium comprises ten companies, namely Marubeni, the project integrator, University of Tokyo, Mitsubishi Corporation, Mitsubishi Heavy Industries, Japan Marine United, Mitsui Engineering & Shipbuilding, Nippon Steel & Sumitomo Metal Corporation, Hitachi, Furukawa Electric, Shimizu, and Mizuho Information & Research.

The first phase of the project consisted of a 2MW compact semi-sub floating wind turbine, the world’s first 66kV floating power sub-station and undersea cables. The turbine has a rotor diameter of 80m and a hub height of 65m above sea level (asl) and is placed on a floater called Fukushima MIRAI. A downwind-type blade, located leeward, was used for the project in order to make the most of the upward wind blowing from the surface of the sea.

Discover Solution 286: Pavements for carbon capture

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