The prospect of an energy island in the North Sea surrounded by windfarms with the ability to power British homes has taken a step closer after National Grid, the UK energy company, revealed that it is in talks about helping to build the project – and claimed it could be done before 2030.

“We are in tripartite discussions over an energy island that the UK would likely connect to,” Nicola Medalova, the company’s managing director of interconnectors, told New Scientist. She declined to name the two other parties in the talks.

The scheme would involve significantly larger offshore windfarms than existing ones, which would be connected to underwater cables that would direct the energy to participating countries.

As a key developer of long-distance cables – including the recent completion of the world’s longest undersea power cable, between the UK and Norway – National Grid’s potential involvement could signal a positive step towards the project becoming a reality. It could also offer a boost to Boris Johnson’s plans, announced this week, to eliminate fossil fuels from UK electricity generation by 2035.

Medalova envisages the energy island being able to combine several technologies. “You could have wind, hydrogen, battery storage, all the rest of it, and that can be connected to one country, two countries,” she said, adding that the project in discussion could have “three connection points”. It could be built as soon as by 2030, she said.

A National Grid spokesperson confirmed there were discussions but said they were not tripartite.

Medalova said she expected that all new interconnectors would be hybrid, with the ability to connect to offshore windfarms, and there was an expectation for windfarm developers and interconnector companies to take a “collaborative, sharing approach” to take pressure off coastal communities.

Other energy network operators in the region that have shown an interest in creating energy islands include TenneT in the Netherlands and Elia in Belgium.

An Elia spokesperson confirmed to the Guardian that it was developing an additional interconnector with the UK, called Nautilus project, and that Belgium planned to build an energy island, but added: “Whether Nautilus will be connected to the Belgian energy island is currently uncertain. That is part of the studies that are currently under way.”

A spokesperson for TenneT said it was “open to talks like this” but it could not confirm that any had taken place.

Meanwhile, the Danish Energy Agency is planning to build energy islands in the North and Baltic seas. The Danish government committed in February to taking a majority stake in a GBP25bn artificial energy island 50 miles offshore in the North Sea.

Prof Neil Strachan, the director of UCL Energy Institute, said the UK’s potential involvement in an energy island was “super exciting” and much needed to meet low carbon energy goals. But he said such a project was likely to cost “tens of billions” and suggested it would need public underwriting.

“You have a much bigger opportunity for such a large facility, but that comes at an extremely high capital cost. I would think that this would need public underwriting, it’s that big, it’s really, really huge.”

He said National Grid seemed like an “obvious partner” for coordinating energy coming from the offshore platform, but it would also require an engineering partnership.

“It will be interesting how much money they [National Grid] are going to put into it. It will also be interesting how they would be able to help coordinate this very large facility with the existing grid, which I think is a big challenge,” he said.

Careful implementation, such as no-fishing zones, would be required to ensure minimal damage to the marine ecosystem, he added.

The UK has so far installed nearly 10 gigawatts of wind power capacity – sufficient to power about 7m homes – and it has the world’s largest offshore wind energy market. China is on track to overtake it by the end of the decade.

Windfarm installations are projected to double to record-breaking levels this year after a slowdown caused by the pandemic, according to the Global Wind Energy Council, largely due to an offshore wind boom in China. Global capacity is expected to rise to 12GW this year, almost doubling the previous record of 6.24GW set in 2019.

The Department for Business, Energy and Industrial Strategy did not immediately respond to a request for comment.