TRANBY, Norway—Offshore wind energy is not a new concept. It has been growing since the facility of Denmark's east coast began supplying power in 1991. Although that 4.95-MW facility has now been decommissioned, the offshore wind market has grown to an impressive 23 GW according to the latest figures from the Global Wind Energy Council (GWEC).

However, the growth of offshore wind has come under pressure because many of the high-wind, shallow-water sites required for the current breed of offshore wind turbines are in sight of land, causing resistance from local communities. However, the demand for renewable energy and wind power, in particular, is growing, seeking developers to look further offshore into deeper waters where the wind is often stronger. The challenge here is that traditional structures fixed to the seabed are impractical, hence the advent of floating wind turbines.

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It was two years ago that the world's first floating offshore wind farm, Equinor's 30-MW Hywind project, started production off the coast of Peterhead in late 2017. Since then, the first turbine has been installed at the Kincardine floating wind farm off the coast of Aberdeenshire, which will have a capacity of 50MW when fully constructed. According to Bloomberg New Energy Finance (BNEF), deals already will provide approximately 237 MW of capacity from floating offshore wind worldwide by 2020.

Given the slowdown of new oil and gas products, it is no surprise to see some of the traditional oil and gas supply chains companies taking more than a passing interest in offshore wind. One such company is Aker Solutions, which is looking at transferable technology into the floating wind sector through a partnership with Principal Power and their WindFloat technology.

WindFloat is a floating foundation for offshore wind turbines that can be applied to various turbine sizes and water depths. The technology allows for wind turbine installation, intervention and maintenance services at the quayside, eliminating the need for specialized and expensive offshore vessels.

In an intriguing strategy, the company is also looking at how wind power can help meet the demand to reduce the carbon footprint of oil and gas productions. On the Norwegian Continental Shelf, in particular, there is a drive to power offshore facilities with land-based power generation.

Equinor is already exploring the possibility of powering oil production utilizing floating offshore wind with its Hywind Tampen project for the Gullfaks and Snorre fields. This would be the first time an offshore wind farm is directly connected to oil and gas platforms.

"We are working with three clients with a similar concept that we call wind for oil," Geir Olav Berg, head of engineering, floating wind, Aker Solutions, said. "We are tendering for work for three separate clients on brownfield and greenfield projects on the UKCS and NCS. This is an alternative to electrification from shore.

"The background for our interest is that in our organization we want to be leading in forging a sustainable future for our company and the planet,” he said. “We have many capabilities in the area of floating wind that can be transferred from our oil and gas expertise."

Aside from the turbines themselves, a floating wind farm consists of the floating structures, dynamic array cables, floating and subsea substation and export cables.

In each of these components, Aker has extensive knowledge and experience.

"We have a long history of delivering floaters from our oil and gas work,” Berg said. "We understand how these structures behave in the water. When it comes to the dynamic array cables, that again is a business we are already in from two of our facilities—here in Oslo and Alabama in the United States. For the substation, the preferred option would be to put it on the seabed for cost savings. Again, we can take some of our technologies from oil and gas, such as the Asgard subsea compression plant, which has some of these elements in it. Finally, we work on oil and gas cables; the only difference here is that it would be offshore to shore, rather than the other way around for oil and gas installations."

It is not only the components themselves that the oil and gas expertise comes into play, but on the complex project and system management that bears many similarities to building and developing an oil and gas field. It is clear that wind alone cannot be the entire solution; it would need back up from gas turbines or battery storage for when the wind is not blowing.

"You need to have some intermittent power sources to take you through the periods where power from the wind is not fully available," Berg said. "Potentially you could use battery systems. These have evolved very significantly over the last five years. These are now industrialized, and several robotic factories are being set up to produce them."

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This battery storage could be located on the windmill itself or the substation if that was floating or even on the rig itself.  

"There are many considerations which need to be made when you're looking at this, but the overall objective is to save cost and also save CO2 emission and wind for oil can do both of these," Berg said.

Offshore