Two 'hybrid assets' could kickstart Europe's offshore supergrid

Two offshore hybrid energy grid projects – involving connections between the UK and the Netherlands and Belgium respectively – have won final regulatory approvals that will trigger long-lead procurement and, backers believe, kick-start development of an integrated North Sea offshore grid.

The offshore hybrid asset (OHA) concept aims for a more efficient distribution of renewable energy across borders by combining electricity interconnection with offshore wind into a single asset. It can optimise grid infrastructure by reducing the need for multiple onshore connections while providing additional channels for energy trades between countries, maximising asset use and boosting competition.

LionLink will connect an offshore facility that Dutch transmission system operator TenneT is developing in order to connect the Nederwiek 3 wind farm to the Dutch and UK grids, the latter via a subsea cable landfall in Suffolk.

The project, which will connect consumers in both countries to 1.8GW of offshore wind resource, was described by Dutch transmission system operator TenneT as the first project of its kind in Europe.

A second OHA called Nautilus will connect Belgian offshore wind farms to the UK grid, with landfall on the Isle of Grain in Kent. It will provide both countries with access to 1.4GW of capacity.

Now for FID

UK regulator Ofgem has published the full details of its “cap and floor” regime for the Offshore Hybrid Asset (OHA) pilot scheme, fleshing out the regulatory framework for the projects. The scheme has been used to provide a regulated route for interconnector development in the UK since 2014.

“This is a tribute to collaboration,” said Ben Wilson, head of National Grid Ventures, who praised “incredible and very successful support” from the UK and Dutch governments in getting cost and revenue sharing arrangements agreed and landfall sites confirmed.

“We are not done yet,” he added. "It will probably take us two years to get to a final investment decision, but we will shortly go to our board to ask for approval for long lead capacity reservations for cables and converter stations.”

Planners hope that a series of hybrid interconnectors will open the way for a much grander vision, whereby wind farms across the North Sea will link into a meshed European transmission grid of the future stimulating, also, the development of so-called energy islands.

This is one of the key themes that is expected to be on the agenda when Germany hosts the third North Sea Summit later this year.

“It’s going to happen,” Manon van Beek, CEO of Dutch transmission system operator TenneT said of LionLink.

“And that’s good news for the companies and our countries, but also in view of turning the North Sea into the green power plant that we want to see. This is hopefully just the beginning for a series of hybrid interconnectors. It’s all about leadership and collaboration, and this starts with a vision.”

North Sea network

This vision was also in the frame when chief executives from several European TSOs presented results of their own pilot study on offshore collaboration last week, aiming to facilitate development of a joint European offshore grid in the North Sea.

This collaboration initiative, known as OTC, found that establishing the North Sea as Europe’s ‘green power plant’ will play a crucial role in helping the continent obtain a secure, affordable and decarbonised energy supply.

In their statement, the OTC group noted that transmission system operators covering the North Sea, Irish Sea and Celtic Sea have increasingly collaborated to advance infrastructure development in line with the objectives of the Esbjerg and Ostend North Sea Energy Cooperation declarations, both of which aim to increase combined offshore wind capacity.

The new analysis includes a grid map that outlines promising cross-border projects as part of a broader offshore regional grid in the Northern Seas.

The OTC intends to submit a set of these conceptual projects for a planned Ten-Year Network Development Plan (TYNDP) next year.

The OTC group called for a robust framework of the kind that attracts greater investment and reinforces the continent’s position as a technological front-runner in offshore wind.

The CEOs said collaboration between TSOs is “already enabling the operation of the world’s largest interconnected electricity system but stressed the need for more political and regulatory alignment.

UK back at the table

Addressing a discussion panel at the WindEurope 2025 event last week, UK climate minister Kerry McCarthy said the two hybrid interconnector projects would bring significant savings to consumers but also showed that “through cooperation we can maximise the potential of wind power across the North Sea.

“We are very aware that we need to reset our relations with the EU," she said.

According to McCarthy a trade summit that will take place in London on 19 May will also serve as a forum to discuss the regulatory framework for offshore assets.

“Let’s keep those conversations going. I think we should have more successes,” she stated.

The LionLink project was following the path of an earlier interconnector between the UK and the Netherlands called BritNed.

“We now have our regulatory arrangements in place, and we've agreed the landfall, which brings certainty to communities that are impacted,” said Wilson.

“It’s very exciting, but there are a few things that we still need to do to really unlock the benefits of these cross-border interconnections,” he added. “We need to make progress on relinking electricity trading arrangements between the UK and the EU.”

“And there's an even more important short-term issue, which is the carbon border adjustment mechanism. Unless we do something about it, it will apply a tax on European consumers to UK electricity imports into the EU”.

Wilson cited research by consultancy firm Afry suggesting that a failure to relink emissions trading could risk an 85% reduction in UK electricity exports to the EU. “That's about eight gigawatts of wind curtailment,” he warned.

“That's a carbon tax applied to clean energy... if the UK is outside the mechanism, and European consumers will also pay that cost,” Wilson said.

An agreement to make the UK part of the mechanism would be a “win-win” situation on both sides, he added.

“We need each other (on energy and defence). We're stronger together. We're in favour of working closely with the European Union,” Wilson stated.