Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Swedes challenge convention with floating wind farms

A Swedish energy firm is planning to create multi-turbine floating wind power platforms in UK waters.

Hexicon this month announced it had raised SEK11.4M (£1M) through a rights issue and planned to use the cash to demonstrate its innovative platforms.

Although the first floating turbine was put into operation near Norway five years ago, and other have followed around the world, Hexicon’s plan is to build the first multi-turbine platforms.

Scotland last year moved to attract floating wind turbine schemes to its water when it boosted subsidy levels. Ministers said in June 2013 that 3.5 Renewable Obligation Certificates per Mwh would be available to such pilot projects.

“Our plan is to build a demonstration project in Scottish waters,” Hexicon chief executive Henrik Baltscheffsky told NCE. “To secure a site we have a dialogue with relevant authorities in Scotland.

“We are working to accommodate their requirements. We would look to start construction in 2017 and generate power for the grid by 2018.”

The company says a remote-controlled winching system for turning the platforms into the wind allows its turbines to be placed closer together than they are on existing wind farms.

Cheaper and more productive

It believes its system will eventually be cheaper and more productive than current fixed wind farms at certain depths as well as opening up new locations for wind energy generation.

Baltscheffsky told NCE that the driving force behind the company’s work was an attempt to slash the cost of creating wind energy.

“By having several turbines on one foundation [platform] you can spread the costs of cables, anchors and other components across three or four turbines,” he said.

Another advantage is the ability to access the wind farms for maintenance.

“You can have a helipad on a platform, along with accommodation [for maintenance workers],” said Baltscheffsky. “If you have 20 foundations, you have 100 turbines, and you can have a mothership.”

Based on the engineering of oil and gas stations, the semi-submergeable, multi-turbine platforms would be water-ballasted and anchored to the sea bed.

After proving itself off the coast of Scotland and on another demonstrator scheme in the Baltic Sea, Hexicon hopes to set up floating wind farms near the Iberian Peninsula and off the French coast.

Locating turbines in deep sea allows them to access strong winds and limits their aesthetic impact. But Baltscheffsky said the floating foundations could eventually prove cost effective in as little as 40m of water.

“The platform has a depth of up to 20m, and you need another 20m [of water] for the anchoring system,” he said.

Deep water cost savings

He said that beyond 40m the cost savings could be even more beneficial.

“There is a very small increase in cost for using the platform at 500m compared to 40m,” he added.

Hexicon believes the demonstration projects will show its system competes with existing foundation methods on price.

“Our technology is yet to be demonstrated but we believe it will be shown to have a cost structure similar to the existing technology of using jacket foundations,” said Baltscheffsky.

“Once we build a park of 20 platforms, we think we can drive down costs by 30%,” he added.

Low carbon technology promoter the Carbon Trust has previously estimated that new foundation design could cut 10% from the cost of energy derived from the 2,500 offshore wind turbines expected to be deployed over the next decade.

The trust announced a trial of “suction bucket” foundations earlier this year.

Readers' comments (2)

  • Wow, having developed and tested my own floating platform I look at this and think 'no way'. The torsion from one corner being high on a wave and another in a trough would be so huge.
    And Scottish waters are not known for being kind.

    1m pounds; for a structure like this might just get a 1/4 scale working, but not much else unless they are doing numerical modelling only.
    Good luck!

    Unsuitable or offensive? Report this comment

  • Would the author say if he has considered whether tidal power and even wave power could be harnessed from the proposed platforms as well as wind power?

    Presumably the design would be a tension leg platform and so not greatly stressed by the highs and lows of waves

    Unsuitable or offensive? Report this comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.