Since the first fixed wind farm was built off the coast of Northumberland in 2000, some 2,652 offshore turbines have peppered the UK coast, contributing almost 17% of the country’s electricity needs.  

They are, according to the UK government, “the backbone of the clean power system”. The Clean Power 2030 Action Plan lays out a roadmap to make clean energy account for 95% of the UK’s electricity supply by 2030. If all goes to plan, offshore wind will be the main source, growing from 14GW in 2024, to 43-50GW by the end of the decade. This is an ambitious goal given that the total global offshore wind capacity in 2021 was 57GW.  

This will involve different kinds of wind farms to those most Brits are used to seeing. Most today are built directly into the seabed. While that’s the cheapest way to build them, they are limited to shallow waters, which only cover 20% of ocean floors. 

Floating wind farms provide an alternative. For starters, they can be built in deeper waters, allowing countries that do not have shallow continental shelves to use them. And unlike fixed-foundation systems, floating platforms are less dependent on seabed conditions, opening areas that would otherwise be inaccessible. In places like California, where the continental shelf drops off steeply from the shore, floating wind farms could provide a renewable source of energy where it wasn’t formally possible. 

The also provide a more reliable source of energy, because winds blow stronger out at sea than on shore. The Hywind floating wind farm off the coast of Scotland reached 65% capacity in its first three months of operation, compared to 45% on average for a fixed wind turbine in the North Sea. Floating wind technology could also provide a huge benefit for local economies. Compared to fixed foundations, floating substructures are larger and heavier, and more difficult to transport over long distances. This means they would need to be built in ports close to the future wind farm.  

The Crown Estate estimates the construction of three floating wind farms in the Celtic Sea could contribute up to £1.4bn to the UK economy and generate 5,300 new jobs in south Wales and southwest England.  

“Floating offshore wind offers a generational opportunity for the UK to be at the forefront of an exciting new global industry. Developing this new technology in the Celtic Sea will open up transformational opportunities for new jobs, investment and growth across Wales, South West England and beyond,” says Gus Jaspert, managing director, marine, at The Crown Estate. 

But while plans move ahead in Wales, another in North Yorkshire has come to an abrupt halt. Earlier this month Ørsted, the world’s largest offshore wind company, announced it would cancel contracts for its Hornsea 4 project in the North Sea. Citing, “continued increase of supply chain costs, higher interest rates, and an increase in the risk to construct and operate,” the company said it expects to pay break-away costs of around £500mn to cancel the contracts. 

The cancellation of the Hornsea 4 project underscores the financial and logistical challenges of building more floating farms. Offshore floating wind costs more per MWh to construct compared to fixed farms, which makes it more reliant on government support schemes.  

There are also few ports in the UK with the right combination of quayside length and water depth to support the manufacturing of large-scale floating infrastructure. And implementation presents another problem. Floating structures must be towed to sea with large tugboats during very calm weather. The largest operating floating wind farm off the coast of northern Scotland took more than a year to install 11 turbines because of choppy seas. Unpredictable British weather makes installing projects with more turbines in a single season difficult and presents challenges of storing the large structures at port until the weather clears.  

Despite the cancellation of the Hornsea 4 project, other offshore floating projects are underway, making the 95% target of renewable energy by 2030 a realistic goal. Scotland has 11 floating projects in the planning phase and two already operating. Looking further ahead to 2050, government projections estimate that floating turbines could provide a third of all offshore wind capacity and employ 97,000 people. What started as a small windmill off the coast of Northumberland in 2000 could result in a £47bn boost to the economy by mid-century.