HTen miles off the coast of Aberdeen, Scotland, a group of five giant wind turbines rotates 190 metres above the North Sea, quietly generating enough clean electricity to power around 35,000 Scottish homes.
This offshore wind farm looks tiny next to the numerous turbines that rise out of the sea on the British east coast. But the Kincardine project represents a different future of clean energy: it is the largest floating wind farm in the world.
Each of Kincardine’s giant turbines is mounted on a floating foundation in waters 80 metres deep. While traditional foundations for offshore wind farms are anchored to the seabed, floating foundations are anchored to the seabed by cables, meaning they can be installed in far larger waters.
The work represents an engineering feat of epic proportions. Each of Kincardine’s turbines is mounted on a floating triangular base that stands nearly 100 feet above the sea surface and is supported by three floating columns, each about 150 feet apart. The framework contains water-filled cans at two of its points to counterbalance the weight of the turbine, which rests on the third.
There are other designs for floating foundations, including a vertical floating cylinder that is stabilized with water, rocks or other heavy materials. These foundations are then anchored to the seabed.
While traditional construction methods may have paved the way for the maritime wind revolution of recent years, it is estimated that up to 80% of the world’s offshore wind resources lie in waters more than 60 metres deep, where fixed wind turbines cannot be built on the seabed. So while huge wind farms have sprung up in UK coastal waters, making the UK a global leader in offshore wind, engineers are working to prove that floating foundations could help the technology reach new frontiers on the open sea.
The technology’s foundations come from the fossil fuel industry, which began building floating oil platforms in the 1960s. It’s no surprise, then, that the leaders in Europe’s emerging floating wind sector are also the largest oil producers: Norway, the UK and Italy.
By building floating foundations for giant offshore turbines, developers hope to expand the world’s wind power capacity beyond the limits of relatively shallow coastal waters and into greater ocean depths, where wind speeds are also higher.
Kincardine’s 50 megawatt capacity is dwarfed by the 1.32 gigawatt Hornsea 2, the world’s largest stationary offshore wind farm, located off the Humber Estuary and capable of powering more than 1.4 million homes. In total, the UK’s floating wind capacity is 80 MW, the second highest in the world after Norway, but is still only a fraction (0.6%) of the 14 GW contributed by the UK’s stationary offshore wind farms.
This is likely to change in the coming decades, although given the UK government’s net zero targets for 2030, floating wind farms are likely to remain in the shadow of their predecessors with a capacity of five GW, while fixed wind farms grow to 60 GW.
Developing offshore wind is a key part of ministers’ plans to cut energy costs by increasing renewable energy production. Electricity bills remain well above levels seen before Russia’s invasion of Ukraine and last Friday UK regulator Ofgem announced that the average annual bill for dual-fuel operation would rise again by 10% to £1,717 from October.
Earlier this month, the Crown Estate, which owns seabed rights off the UK coast, invited pre-qualified developers to submit their plans to build three floating offshore wind farms in the Celtic Sea. By approving the plans through the application process, it is hoped that the construction of floating wind turbines can be accelerated.
Industry association Renewable UK expects floating offshore wind farms to account for well over half of UK offshore wind energy generation by the 2040s.
“The future of offshore wind lies in floating offshore wind farms,” says Jane Cooper, director of offshore wind at Renewable UK. “It’s the natural progression. It allows the UK to take a huge step forward by building the next generation of projects further out to sea, in deeper waters where wind speeds are even higher.”
This heralded shift for the offshore wind industry will not be without challenges. Recently, there has been a wave of financial turmoil for developers after soaring cost inflation and higher interest rates combined with supply chain disruptions to disrupt construction schedules across the industry.
Danish developer Ørsted announced on August 15 that it had been forced to postpone a major project off the northeast coast of the United States, months after canceling two nearby projects and cutting hundreds of jobs.
For floating offshore wind, the biggest challenge is cost. This is made clear in the guidelines for the government’s upcoming auction of clean energy subsidies, which set the maximum price for fixed offshore wind developers at £73 per megawatt hour, and for floating offshore wind developers at £176 per MWh.
Norwegian energy company Equinor, a leading developer of floating wind farms, believes that with the right policy support, the costs of floating wind farms could approach those of their fixed counterparts by the early 2030s – just in time for the expected boom in floating projects in Europe and around the world.
For the UK, the second challenge lies closer to home. Britain’s ports are too small and under-resourced to accommodate the huge turbines and floating foundations required to meet the government’s ambitions. Billions of dollars in investment will be needed to make the ports bigger and deeper, while upgrading their facilities to manufacture and assemble the gigantic infrastructure required.
Britain’s first floating wind farm, Hywind Scotland, is docked in the Norwegian port of Wergeland over the summer to carry out maintenance work that could not be carried out in the UK. Scottish Enterprise described the decision to tow the turbine foundations across the North Sea as a “missed opportunity”.
“We need to attract £4 billion of public and private investment in new port infrastructure to accommodate floating wind turbines by the end of this decade,” said Cooper.
“This would increase economic activity across the UK by £18 billion and the floating wind industry could support 45,000 jobs by 2040.”
The UK wind industry is keen to seize the industrial opportunities presented by the new technology and help countries such as Portugal, Japan and the USA, whose coastlines are less favourable to fixed wind turbines, to expand their wind energy production.
One early UK success story is Bristol-based Rovco. Specialising in underwater surveying and robotics, the company has become one of the UK’s fastest-growing start-ups in recent years thanks to its digital approach to providing data solutions to offshore wind developers such as SSE and Iberdrola. The company is expected to reach “unicorn” status – a valuation of more than $1 billion – later this year as it seeks further funding to finance its global expansion.
Brian Allen, CEO of Rovco, says wind energy offers “a huge, bright future for our business.” He adds: “If you look at where we were in 2014, there weren’t very many offshore wind farms. But the huge leap in technology and economies of scale that have been achieved over the last decade are proof of what we can achieve with floating offshore wind in the decades to come.”
The pace of the coming changes will likely surprise many, says Allen.
“Most people I talk to who should know this just don’t understand how big this (floating wind) industry is going to get. Most of the areas where the industry wants to develop offshore wind are in very deep water, and these wind farms have to float.
“Even though the UK is literally leading the world in developing offshore wind, people really have no idea. It’s coming like a freight train, but people are blind to it.”
