Wind on the water: The Culzean floating turbine project

As part of TotalEnergies’ efforts to decarbonise operations, a UK project team is piloting the use of floating offshore wind to provide power to offshore oil and gas platforms. Project Manager Charles Howorth tells us about the unique turbine design being trialled at our Culzean platform and how the technology could help transform the industry.

As we navigate the energy transition, energy from fossil fuels will remain a key part of the mix. While TotalEnergies will continue to produce gas and oil to meet the needs of society and support security of supply, we’re also working tirelessly to reduce the emissions associated with it. 

The Culzean floating wind turbine project is one of many projects we are working on to help reach our 2030 target of reducing direct emissions by 40% at company level.

“The intention of this particular project is to build a floating wind turbine alongside Culzean, to provide power to the gas-producing asset, but not all the power,” says Project Manager Charles Howorth. 

“It’s what we call a hybridisation project,” he continues. This means the asset will be powered by a hybrid of energy types: renewable power from the wind turbine and gas power from two of the existing gas turbines on the asset. It is estimated that the floating wind turbine will replace around 20% of Culzean’s current power requirement, reducing emissions at the same time.

An innovative design

“One of the two objectives of the project is to trial hybridising power to a producing asset, and the other objective is to qualify the new technology,” explains Charles. 

This technology is a semi-submersible light floater hull designed by Ocergy, a green energy company headquartered in the US, with operations in France.

The turbine itself is a Vestas V112, which refers to the diameter of the turbine, about the size of the London Eye. “It’s fairly large physically, but at 3MW, it’s not generating as much power as many modern turbines, which can go up to 15MW,” says Charles. 

“The reason we opted for this turbine is that we wanted a tried-and-tested model, which we could be sure of, while experimenting with the attached floater, which is significantly smaller and lighter than other designs.”

Ocergy’s innovative design comprises a Compressed Air Trim (CAT) system with three outer columns. “The downwind column is filled with water, so it remains stable when the wind’s blowing towards it,” explains Charles. 

“When the wind direction changes, and the nacelle rotates, air is pumped into the other two columns so the column which is now in downwind position fills with water, keeping the turbine stable, and helping to optimise production.”

The obvious advantage to this design being lesser in weight and size is that it helps bring down the cost in materials, manufacture and transportation. But arguably the most exciting thing about this design is that it is modular, making the assembly process easier and repeatable.

An industrial solution

“As the steel floater is fabricated in components, the different elements can be made at separate sites around the world simultaneously,” says Charles. 

“All the pieces can then be sent to one assembly location, where it’s bolted together using compact flanges – a faster connection method to designs which rely on extensive welding. Every aspect of the design gears towards quick assembly.”

If successful, the immediate rewards of this project for TotalEnergies would be in reducing emissions at Culzean, but the wider implications for the industry going forward are huge. 

By fabricating the components globally and assembling them close to the project site, a broader supply chain can be utilised, and the fully commissioned turbines can be installed offshore at the rate of at least one unit per week. This efficiency is a key requirement for the economic viability of commercial-scale floating offshore wind projects.

Powering up

So when can we expect to see the project hit the water? “Archer Wind have been awarded a contract for the engineering, procurement, construction, installation and commissioning, with work on the detailed design already under way,” says Charles. 

“We received the final investment decision in May, and rolling of steel began in November. All going to plan, we’ll go into full fabrication in January and have the turbine in the water and supplying power to Culzean by Q4 2025.” 

“This is a very exciting project which has the potential to offer the industry a viable approach to renewable power generation for offshore oil and gas installations, and the reduced emissions that come with that,” said Nicolas Payer, Managing Director of TotalEnergies Exploration & Production in the UK.

“Our focus is on testing the technology, but in doing so we’re also reducing Culzean’s reliance on power generation from non-renewable sources and cutting emissions from our operations. 

“The potential for other assets – both in the North Sea and worldwide – to reduce their emissions following this trial is hugely significant for our industry.”