Floating wind is making great strides

Nearly all of Europe’s existing ofshore wind is bottom-fxed right now. But that only makes sense commercially up to 60m sea depth. Beyond that it is more cost-competitive to install foating ofshore wind turbines.

According to WindEurope, foating wind is now rapidly coming of age. And this is going to allow for ofshore wind development in the Mediterranean, the Atlantic, and other sea basins with large water depths. Although Europe has four small foating wind farms today, totalling only 176MW of capacity, the amount of power generated by foating wind will soon expand. France is now tendering a 250MW foating wind farm of Brittany and they’re about to tender two more

250MW foating projects in the Mediterranean. Large-scale foating wind auctions are expected to take place this year in Spain, Portugal, and Norway, too, whereas UK has already tendered sea space development rights for over 15GW of foating wind.

Big challenge

Europe can be confdent it will have 3-4GW of foating wind in operation by 2030. And it is not unreasonable to think it will have 10GW by then if governments back up their expansion targets with the right policies. The next big challenge for foating wind is to consolidate the diferent foundation models into a few and develop large scale manufacturing, assembly and transport of those models. Ports need to invest signifcantly in space, quaysides and berths to support the transport of the rapidly growing volume of bottomfxed wind turbines. Unlike bottom-fxed ofshore wind farms where the assembly and installation of turbines happen at sea, for foating wind turbines most of these activities take place around ports when it concerns the foaters although the turbines themselves are the same that are used in bottom-fxed ofshore wind. The development of manufacturing facilities for big foating structures, such as a concrete or steel substructure of 3,000t and with 80m sides, will need considerable investments. France and the UK are already planning public fnancial support for this.

Costs come down

Floating wind costs more than bottomfxed ofshore wind today. But the costs are coming down and will continue to do so with the use of scale-efects and the introduction of competitive auctions. The EU has contributed signifcantly to this cost reduction with its COREWIND project. The project optimised the design of two foating structures for a 15MW turbine, tested new solutions for cables and mooring systems and identifed improved ways of transporting, installing and operating foating wind farms. It helped reduce the cost of foating wind by up to 18%, which is equivalent to USD63/MWh in the best scenario.

Giles Dickson, CEO of WindEurope states, “Floating wind is advancing at a rapid pace. The demo projects have worked. Now is the time to scale-up to large projects. Watch out for France’s 250MW tender which will conclude this year. Floating wind opens the Mediterranean and other deeper seas to ofshore wind. Norway, Spain, and Portugal all plan tenders this year. Italy, Greece and Ireland are preparing to join in soon and the UK has big ambitions as well. We can expect Europe to have 3 - 4GW of foating wind by 2030.” i. windeurope.org

Corewind

Compared with fxed ofshore wind, cost-efciency is still a key issue for foating wind to deploy in Europe. The COREWIND project therefore aimed at achieving signifcant cost reductions and enhancing performance of foating wind technology through innovation and optimisation at all phases of a project’s lifecycle (design, choice of components, operations & maintenance). On 25 April, during the project’s fnal event at WindEurope’s Annual Event in Copenhagen, COREWIND partners announced they achieved a cost reduction between 11% and 18% for foating ofshore wind technologies, depending on the scenario and site conditions analysed.

During the event the attendees could learn about the innovative solutions that helped achieve this fnal cost reduction. These solutions include, for example:

• optimised designs of two foating sub-structures (concrete spar and semi-sub) for 15MW foating wind turbines in farms;

• solutions to optimise the mooring design including an optimisation tool and the analysis of several innovations such as shared anchors or shared mooring lines;

• analysis and comparison between diferent cable system confguration options;

• solutions to optimise O & M strategies such as major component exchange strategies, impact of using crane vessels, self-hoisting crane;

• more than 135 experimental tests carried out to validate the solutions including wind tunnel and basin tests; i. corewind.eu

• the ‘FowApp’ application which allows to calculate the full Levelised Cost of Energy and the Life Cycle Assessment of an asset from cradle-to-grave.

In total, more than 25 exploitable results have been identifed within the project, including product services but also transferable knowledge.