The world’s first floating windfarm is under construction near the coast of northeast Scotland, with the first two turbines already floating in place. Another five are awaiting transport in a fjord in western Norway. The groundbreaking Hywind project uses a 78-meter underwater ballast, as well as three mooring lines connected to the seabed, to keep the turbines upright.
Notably, the project is being developed by Statoil, a Norwegian oil firm trying to diversify to include cleaner energy.
According to the company’s low-carbon division head, Irene Rummelhoff, the floating technology opens up new opportunities for wind power.
“It’s almost unlimited. Currently we are saying [can operate in] water depths of between 100 and 700 meters, but I think we can go deeper than that. It opens up ocean that was unavailable.”
The North Sea has seen many windfarm projects in recent years, a result of its unusually shallow depth. In much of this area, turbines can be mounted onto steel poles fixed directly to the seafloor. However, these fixed-bottom turbines are limited to areas with a depth less than 40 meters, which means there is little hope of installing them on coasts with steep shelves, such as the Pacific coast of the US.
“If you look at coastlines around the world, there’s few that have sufficient area at depths down to 40 metres so if they want to deploy offshore wind, they need to introduce floating wind,” Rummelhoff explained.
Floating windfarms could open up new clean energy opportunities in the Atlantic and the Mediterranean. Importantly, putting the windfarms further out to sea could help to avoid popular objections to ruining ocean views along coasts, which stopped a project off the Dorset coast.
The Hywind project is small compared to other windfarm projects, intended to power just 20,000 homes. One project in construction off Yorkshire coast will power 800,000.
“Looking to the next decades, there might be a point where floating is bigger than fixed based,” according to Steven Barth from IEA Wind, an intergovernmental organization covering wind power in 21 countries.
For the moment, cost is the primary factor holding back floating windfarm technology. To move the massive turbines, Statoil has to hire the second largest lifting vessel in the world to move them into place and get them floating. As the first of its kind, the technology also necessitates a complex supply chain, currently including 15 separate contractors. For the moment, experts have said a conventional windfarm with the same capacity would cost half as much.
As subsidy from the Scottish government is making the current project possible.