Floating wind technology designers need to devise a way of manufacturing their platforms “at the same speed that [OEMs] make turbines” if the fast-emerging sector is to industrialise at a pace that will see tens of gigawatts installed in the coming decades, MHI Vestas’ UK country manager has said.

“You have to get up to multiple units per week – I’m not going to tell you exactly how many, but that’s the challenge,” said Julian Brown, speaking at an Energy Industries Council forum.

“The ‘Takt [manufacturing through-put] rate’ is the thing. If the manufacturing lead time from cutting first-metal [for a floating wind foundation] to when it falls onto the production line is two weeks, that’s great,” he stated.

“But if it's 12 weeks or 36 weeks as some substructures might be, you have an unbelievable number of foundations that are works in progress, and then you’ll need a [quayside] manufacturing site with many hundreds of acres [to accommodate a floating wind project’s foundations before they are towed out to site] to facilitate your manufacturing through-put.

"From [foundations to] cables to mooring to anchors – we [as a turbine OEM] are very chill about floating ... but the Takt rate has to be stepped up.”

For this reason, Brown added, he favours steel over concrete as a material for floating wind platforms: “I worry about the cure-time needed [for concrete] – if you have a Takt rate of three weeks’ cure-time, how on earth are you going to make multiple units per week?”

“And then storage: when you do build the 50-100 units you’ll need [for a utility-scale floating wind farm] where are you going to put them? Not on land, so then, in the water – and this needs thinking-through – water depth of at least 12-15 metres for draught and a huge area – in the UK the only place I can see handling this is [Global Energy Group’s] Nigg [yard] on Cromarty Firth [in Scotland].”

Brown, who took on the top UK job at the Japanese-Danish offshore turbine maker last August, following roles including that of chairman of industry advocacy body RenewableUK and head of (now-defunct) OEM Areva Wind, also spotlighted that platform designers needed to get ready for turbines ‘way bigger’ than the 10MW models his company and rival Siemens Gamesa are now selling into the offshore wind market.

“It’s a no-brainer. Yes, [this size of turbine] can’t be installed at the moment with the existing cranes we have. But if look at the turbines that have been announced in the last year, they are within spitting distance of 15MW [nameplates].

“For us to assume that we will be using 10MW machines in ten years is naïve.”

The floating wind sector has long made the argument that the first-generation of concepts now in the water – Equinor’s Hywind, Principle Power’s WindFloat and Ideol’s ‘damping pool’ design – would see a per-unit cost benefit from being fitted with super-size machines as the enlarging of the platform would not have to match the upscaling of the turbine nameplates.

“It is well-known that the economics of floating [foundations] benefit from larger capacity turbines,” Brown acknowledged. “But we should be planning for turbine sizes that are massively bigger than they are now.”

In April, MHI Vestas was tapped to supply five of its 9.5MW V164 turbines for Scotland’s 50MW Kincardine floating wind array, setting the seal on the rebirth of a project that came close to being iced last year – and marking the first order for 9MW-plus machines for a floating wind project.

From a single industrial-scale prototype in 2009, floating wind is now progressing at a clip toward commercialisation, with arrays online or in development off Scotland, Portugal and France, Korea and in the US Pacific, as well as off Japan.

With a next generation of floating wind concepts now heading for prototype testing, many analyst forecasts point to a fleet of 15GW or larger by 2030, with sector standard-bearer Equinor – which brought the first multi-unit array, the 30MW Hywind Scotland, online in 2017 – seeing floating wind “out-competing” bottom-fixed on price by then.

A study last year from the Scottish arm of UK seabed landlord the Crown Estate calculated development of a fully-fledged floating wind power sector in Britain could expand into a market worth almost £34bn ($43.5bn) by 2050 while creating as many as 17,000 new jobs.

Wind

Floating wind must speed up ‘Takt time’: MHI Vestas UK chief