Floating turbines may usher in a new wave of offshore wind

Floating turbines at the Hywind Scotland project in the North Sea
Floating turbines at the Hywind Scotland project in the North Sea 

Brits are used to seeing offshore wind turbines by now, the UK has more installed capacity than anywhere else, generating about 10% of total electricity

Offshore wind farms have substantially increased clean-energy production all over Europe and driven down the price to a level competitive with fossil fuels. As the number of wind turbines increases all over the world however, relatively shallow, offshore locations for wind energy are filling up.

Floating turbines offer a solution, they can be sited in waters up to half a mile deep, where the world’s strongest and most consistent winds blow. It also removes aesthetic objections by being out of view from the coast.

Illustration of floating wind turbines using chains to anchor to the sea floor
Floating wind turbines use chains to anchor to the sea floor up to a half a mile deep

In windswept northern Scotland, where abundant wind arrays both on land and coast vie for limited space, five 574-foot-tall turbines have been constructed 15 miles offshore. Hywind Scotland generates enough electricity for more than 20,000 homes and is the first wind energy array that floats on the sea’s surface rather than being dug into the ocean bed. Proponents say the technology heralds a new generation of green energy.

HyWind Scotland floating wind farm
Siem Moxie on charter to Statoil’s HyWind Scotland floating wind farm
Image: Siem

Giant masts and turbines sit in buoyant concrete-and-steel keels that enable them to stand upright on the water, much like a fishing bobber.

Although onshore wind parks are the most cost-effective solution, they have been met with stiff opposition from activists, who object to their marring the landscape, the proximity to their homes, and the impact on nature, particularly birds. In some countries, such as Germany and Norway, citizen opposition has nearly ground onshore wind to a halt.

Some renewable energy experts remain sceptical that the high costs of floating offshore wind turbines, Currently the electricity they generate is often almost twice as expensive as near-shore wind turbines and three times that of land-based wind turbines. Will come down far enough to rival other clean-energy technologies?

A floating turbine being pulled out to sea off the coast of Portugal
A floating turbine being pulled out to sea off the coast of Portugal for the WindFloat Atlantic project, now under construction. Image: DOCKGO/WINDFLOAT ATLANTIC

Floating wind power has enormous potential to be a core technology for reaching climate goals

Advocates of floating wind arrays note that the costs of onshore and near-shore wind energy have been steadily falling as the efficiency of these technologies has been rising; the same trends, they contend, are likely to lower the costs of floating offshore wind.

Ocean Desk Top Ten (title graphic)

10 facts about offshore wind…

  1. Offshore Wind Resources Are Abundant: Offshore wind has the potential to deliver large amounts of clean, renewable energy to fulfil the electrical needs of cities along coastlines

2. Offshore Wind Turbines Can Be Extremely Tall: In order to capture the abundant wind resources available offshore, offshore turbines can be over 500 ft tall with blades the length of a football field

3. Offshore Wind Components Are Getting Larger: Offshore wind turbine components are transported by ships and barges, reducing some of the logistical challenges that land-based wind components encounter, such as narrow roadways or tunnels.

4. Offshore Wind Farms Use Undersea Cables to Transmit Electricity to the Grid: Electricity produced by offshore wind turbines travels back to land through a series of cable systems that are buried in the sea floor.

5. The Majority of Offshore Wind Resources Are in Deep Waters: It is unclear whether any significant harm is done to birds by onshore wind. It is crucial to get a handle at an early stage on whether there is any serious harm to marine biodiversity as we embark on building multi-gigawatt offshore wind farms and other energy infrastructure in the sea.

An offshore wind farm
Wind power broke records during the ‘beast from the east’ | Image: Peter Byrne/PA

6. Offshore Wind Turbines Can Float: Several companies are developing innovative floating offshore wind platforms for use in deep waters. Three kinds of floating platforms are spar-buoy, tension leg platform, and semi-submersible.

7. Offshore Wind is Right on Time: Offshore winds are typically stronger during the day. Most land-based wind resources are stronger at night, when electricity demands are lower.

Offshore windfarm
World’s largest offshore wind farm, the Juncker Plan has allowed the UK to invest in offshore wind power | Image: NHD-INFO

8. Offshore Wind Resources are near people: Millions of people live within reach of power from offshore wind

9. Offshore Wind is Here To Stay: Offshore wind projects are in progress all over the world.

10. The UK is the world-leader in offshore wind: With huge potential to continue expanding and contributing towards electricity sourced from renewables. It’s a comparatively new industry in the maritime sector and the scale at which it’s growing is unprecedented.

Related Article: Floating offshore wind turbines are coming


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