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Floating offshore wind comes of age as Hywind Scotland takes shape

Mon 07 Aug 2017

Floating offshore wind comes of age as Hywind Scotland takes shape
Hywind Scotland is taking shape off the Scottish coast

Floating offshore wind is no longer consigned to the laboratory – it’s ready to be rolled out on an industrial scale

 

According to the latest report from WindEurope, not only has the technology for floating offshore wind reached maturity, costs are also predicted to plummet in the coming years. One of the key advantages of floating offshore wind is that turbines are located further away from shores in areas with higher average wind speeds without depth constraints.

Turbines can be significantly larger on floating installations, and construction, installation, operation and maintenance costs could be lower than on fixed sites. Capacity can thus be improved leading to an increased generation of electricity, allowing for cost reductions of 10 per cent by 2020 and 25 per cent by 2030.

Ivan Pineda, WindEurope’s director for public affairs, said “Floating offshore wind is no longer an R&D exercise. The technology has developed rapidly in recent years, and it is now ready to be fully commercialised at utility scale projects. Adding this option to the market means more offshore wind in total, and it’s this extra capacity that we will need to meet the 2030 goals.”

Floating offshore wind offers a vast potential for growth – 80 per cent of all the offshore wind resource is in waters 60 m and deeper in European seas, where traditional bottom-fixed offshore is less attractive. At 4,000 gigawatts, it is significantly more than the resource potential of the US and Japan combined.

WindEurope says tapping into this inexhaustible resource will be key to expanding the overall capacity of offshore wind and supporting the EU in reaching the target of 27 per cent of energy by renewables by 2030. As highlighted in WindEurope’s latest report, Unleashing Europe’s offshore wind potential, offshore as a whole could in theory generate between 2,600 TWh and 6,000 TWh per year at a competitive cost – €65/MWh or below, representing 80–180 per cent of the EU’s total electricity demand.

Among the floating offshore wind projects in Europe are: Hywind Scotland, a 30 megawatt (MW) project in Scotland expected to be commissioned in 2017; Kincardine, 48MW, Scotland, from 2018; Dounreay Tri, 2 x 5MW, Scotland, 2018; WindFloat Atlantic, 30MW, Portugal 2018/9; French pre-commercial windfarms 4 x 25MW, 2020; Atlantis/Ideol, 100MW, UK, 2021; Gaelectic, 30MW, Ireland, 2021.

Late July 2017 saw the first Hywind Scotland floating wind turbine arrive in Scottish waters, the turbine having been installed on the floating foundation in Norway and then towed to the UK. By the end of July, all of the Siemens Gamesa 6MW turbines that will make up the Hywind project had been installed on their foundations. The floaters, which use a spar-type substructure, are being towed from Stord on the west coast of Norway to Scottish waters where they will be installed 25 km off the coast of Peterhead in Aberdeenshire in water depths ranging from 90m to 120m.

“Siemens Gamesa views the floating windfarm market area the same way as we did with offshore windfarms in the early beginning: it is a very interesting area that is initially a niche market. This niche may, however, develop over time into a large market. It is a niche in which we would like to build a strong position,” said Michael Hannibal, chief executive, offshore at Siemens Gamesa Renewable Energy.

The Hywind concept has already proven its effectiveness back in 2009, when Statoil and Siemens Wind Power installed a 2.3MW turbine for the first full-scale floating wind turbine project, the Hywind Demo.

Apart from the above-mentioned, there are a growing number of research, development and demonstration projects underway in Europe.

LOC Group has been selected to head a consortium of companies in a Carbon Trust-led floating offshore wind joint industry project (JIP) to investigate the infrastructure and logistics challenges faced in utility-scale projects.

The investigation report and recommendations, which has been commissioned by the Carbon Trust and JIP partners Dong Energy, Engie, Eolfi, E.ON, Innogy, Kyuden Mirai Energy, Statoil and Vattenfall, will help drive the commercialisation of floating wind technology. The consortium includes Portuguese offshore renewables consultancy WavEC and offshore geoscience and geotechnical engineering consultancy, Cathie Associates.

Building on its members’ extensive experience in the offshore wind industry, and drawing on new technical information and knowledge, the consortium will outline key solutions for the realisation of floating offshore windfarms with a capacity of 500MW.

The report will first categorise all floating wind platform solutions currently being trialled by industry to provide recommendations for overcoming foreseeable challenges in the construction of 500MW windfarms, regardless of the type of floating technology being used.

LOC’s report will outline the essential logistics needed for the assembly, storage and construction of floating offshore wind platforms, and, in particular, cover the details of dockside construction, marine transportation and installation operations.

Bureau Veritas has issued a preliminary design approval for a floating offshore wind turbine foundation designed by DCNS Energies. The floating foundation is based on a semi-submersible and was designed to be competitive, adapted to mass production, easily towable, connectable and disconnectable, and adaptable to site conditions and local industrial environments.

Approval was provided as part of the General Electric and DCNS Energies Sea Reed project, a floating offshore wind turbine development initiative supported by ADEME, the French Environment and Energy Management Agency.

Matthieu de Tugny, chief operating officer, senior vice president and head of offshore at Bureau Veritas, said “We are seeing increasing interest in floating offshore wind technology as demand for wind power increases. Foundations fabricated onshore can be installed in deep water. Because of their low environmental impact during installation and application in deeper waters, we can see that demand for floating offshore wind will grow.”

Preliminary design approval implies that the basis of design has been approved. The design is feasible and achievable and contains no technological issues that may prevent the design from being matured.

Co-operation between Bureau Veritas and DCNS Energies will continue to grow with a floating wind project planned to be deployed between the Groix and Belle-Île Islands. The array will consist of four 6 MW GE Haliade turbines installed on a hybrid (steel and concrete) version of DCNS Energies’ floating foundation.

DNV GL updating design standard for floating wind turbine structures

DNV GL says it expects to publish a revised and updated version of its standard for floating wind turbine structures last this year. It first issued DNV-OS-J103 Design of Floating Wind Turbine Structures in June 2013. The standard was based on a joint industry effort with representatives from manufacturers, developers, utility companies and certifying bodies.

It now plans to publish a revised version of DNV-OS-J103 in 201, as part of the harmonisation of the DNV GL codes for the wind turbine industry following the merger between DNV and Germanischer Lloyd in 2013.

The updated standard will reflect experience gained after the first issue was published in 2013 as well as the current trends in the industry. 

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