The simple basis for the floating approach, as opposed to conventional bottom-fixed offshore wind utilities, is that it allows turbines to be installed in deeper waters. Hywind is situated in water depths of close to 130m, whereas farms directly fixed to the seabed are found in depths of up to 50m. As a rule of thumb, winds are stronger the further out to sea. In Hywind’s case, average wind speeds in this area of the North Sea are around 10m/s. 

“One of the key advantages of floating is that turbines can be located in areas with much higher average wind speeds, giving turbines the ability to harness the best possible wind resources without depth constraints,” says Andrew Canning, a spokesperson for Brussels-based trade body WindEurope. “The significant increase in turbine sizes is another factor. Larger turbines are a good fit for floating, as they can withstand high wind speeds and generate higher output per turbine.”

Ever since Statoil began towing the turbines over from Norway, discourse has centred around whether floating wind farms could be installed off other coastlines with especially deep waters. Candidates include Japan, the west coast of the US, France and Portugal, says Canning, while Statoil foresees future turbines operating in depths of up to 800m. 

Are we in danger of getting carried away? Perhaps. Hywind has not only enjoyed the advantage of being developed by a large, successful company;  it was also granted support by the UK Renewable Obligation Centre (ROC) subsidy scheme, which pledged £140/MWh to help Statoil recover its costs. The ROC scheme has since been shut down, which will make it doubly difficult for smaller pilot projects to get off the ground – in the UK, at least. 

A lack of funding has already been the downfall of less-established developers, such as Dounreay Tri, which was planning to launch a floating farm off the Scottish coast later this year. The group went into administration in July 2017, making it unlikely we’ll see anything emerge anytime soon.

“It is difficult for floating wind farm developers to find subsidies,” says Tom Harries, an analyst at Bloomberg New Energy Finance. “And without dedicated subsidies, the sector will stall. At the moment, only France, Japan, Portugal, the US

and Norway have either pledged support or are planning support for floating wind. Even so,

most of the support is for small

demonstration projects.”

While the costs of conventional offshore wind may have fallen steeply in recent years – to the point where some companies, such as Denmark’s Dong Energy, are pursuing schemes without any subsidies – Harries doesn’t expect floating wind farm projects to follow suit. For floating wind to stand any chance of being competitive with other forms of low-carbon generation, we first need to bigger farms come into play. But without the funding to do so, the sector finds itself in a chicken and egg scenario.

“In order to bring down costs and become a feasible large-scale generation technology, the sector needs scale and multi-hundred megawatt projects,” says Harries. “It is only then that floating wind can prove its cost reduction potential, which is serial foundation manufacturing, easier and quicker installation – without the need for heavy lift vessels – and greater yield from stronger winds further from shore.”

But there is some evidence to suggest that project overheads could see a steeper drop. Statoil claims to have brought down its costs by 80% since it first trialled the Hywind Demo off Karmøy, south Norway, in 2009. The group is also on the record as claiming costs for its future projects could realistically be reduced by a further 40%-50%.

The UK’s Energy Technologies Institute also believes floating wind could be competitive within the next decade, predicting costs of less than £85/MWh. According to Canning, the costs of floating offshore wind “have fallen and will continue to fall with upcoming volumes”. He credits this to economy of scale. 

“With higher capacity factors, as a result of being located in areas with higher wind speeds, the levelised cost of energy will therefore be reduced. Floating offshore wind is now a viable technology and ready to be rolled out on an industrial scale.”

By Canning’s reckoning, the potential for floating wind is “4,000GW in Europe alone”. But there are caveats. Success hinges on investor commitment in projects, potentially aided by financial instruments, “such as guarantees and other hedging instruments”. 

Governments could also play a role in bridging public and private financing to offer assistance. Floating will also require sizeable, sustained investments in R&D, he says, “ to accelerate cost reduction, particularly in technologies very close

to commercialisation”.

Harries, however, can’t see governments dipping into the coffers just yet to support new floating wind farms, especially with conventional offshore prices as low as they stand.

“Developers of bottom fixed offshore wind are already weaning themselves off subsidies by offering to build wind farms using market prices alone,” he explains. “Floating wind is years away from achieving this. As the price of bottom fixed offshore wind plummets, why would a government pay more for floating wind?”