Vertical axis wind turbine (VAWT) designs have long been seen to hold untapped promise, with experimental models having undergone development and trials in onshore settings, and several high profile pilot units, including French contractor Technip’s Vertiwind, WPL’s Aerogenerator, and a concept collaboration between EDF and Nenuphar, but none reaching commercialisation.

The US government, through its Atlantis technology development programme is underwriting an up-to-15MW concept hatched at the University of Texas at Dallas, but Sweden’s SeaTwirl stands alone currently among commercial-scale VAWT designs heading for the water.

A study published by Oxford Brookes University in the UK last year concluded VAWTs would “outcompete” the mainstream models now being built in their thousands for projects around the world.

The research, based on more than 11,500 hours of computer simulation, found that VAWTs – which fly angled, upright blades around a rotor shaft turning a direct-drive transmission – would be “far more efficient” than traditional turbines for industrial-scale wind farms, and when installed “in pairs” would up each other’s performance “by up to 15%” more.

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