The world’s first floating offshore wind farm began delivering electricity to the Scottish grid today...
The 30MW installation, situated 25km (15.5mi) from Peterhead in Aberdeenshire, Scotland, will demonstrate that floating offshore wind farm energy can be harvested in deep waters, miles away from land, where installing giant turbines was once impractical or impossible. At peak capacity, the wind farm will produce enough electricity to power 20,000 Scottish homes.
The installation of the floating offshore wind farm, called Hywind Scotland, is also interesting because it was built by Statoil, a Norwegian mega-corporation known for offshore oil drilling. Statoil has pursued offshore wind projects in recent years, using the company’s experience building and managing infrastructure in difficult open sea conditions to its advantage.
Hywind Scotland began producing power in September, and today it starts delivering electricity to the Scottish grid. Now, all that's left is for Statoil and its partner company Masdar to install a 1MWh lithium-ion battery, charmingly called “Batwind,” on shore. Batwind will help the offshore system regulate power delivery and optimize output.
After a number of small demonstration projects, the five 6MW turbines are the first commercial turbines to lack a firm attachment to the seafloor. They're held in place using three giant suction anchors, which are commonly used in offshore oil drilling. Essentially, an enormous, empty, upside-down “bucket” is placed on the seafloor, and air is sucked out of the bucket, which forces the bucket downward, further into the seafloor sediment. The 2013 video below helpfully shows exactly how that works.
The towers, which extend 176m (577ft) above the water and 78m (256ft) below it, are then moored to the three anchors. The towers have a rotor diameter of 154m (505ft). A cable running from each delivers electricity to a power station onshore.
The turbines are quite high-tech as well. According to Statoil, each tower is capable of pitching its blades to reduce unwanted motion and optimize power output depending on the wind direction and strength.
The project cost about 200 million pounds ($263 million) to construct , according to Bloomberg. But the UK government will help Statoil recover that cost. It has pledged to deliver 3.5 Renewable Obligation Certificates (ROCs) to Statoil for the power produced by Hywind Scotland, which translates to about 140 pounds ($185) per megawatt-hour on top of the current wholesale power price in the UK, which is about 49 pounds ($65) per megawatt-hour.
That's not cheap, but Statoil is confident that it can now build these floating wind farms faster and cheaper. Irene Rummelhoff, the executive vice president of Statoil's New Energy Solutions business, said in a press release,
“Statoil has an ambition to reduce the costs of energy from the Hywind floating wind farm to € 40-60 €/MWh by 2030."
But why build floating offshore wind farms in the first place? The farther out you can place offshore turbines, the steadier and faster the wind is. It also comes with the added benefit of avoiding any community arguments over clean ocean views, not to mention the fact that unimaginably large rotor components can be delivered by sea rather than by land, where roads have weight limits and turns can get tricky. In addition, Statoil claims that 80 percent of offshore wind resources are in deep water, where fixed installation would be prohibitively expensive.
So floating offshore wind offers a way to bring more wind power online in a theoretically cheaper fashion. Wind is already seeing the benefits of a significant learning curve. In January, The Crown Estate, which manages the UK seabed (and has leased the necessary acreage to Statoil for Hywind Scotland) released a report saying that the cost of offshore wind had come down 34 percent in the last four years. Another report published in
Floating Offshore Wind Farm - Nature Energy
In November 2016 estimated that advances in turbine technology would reduce the cost of wind by 24 to 30 percent by 2030. Hywind Scotland is a step in that direction.