Dutch grid operator TenneT is proposing the development of an artificial offshore island in the North Sea, which it says would deliver wind energy in a more economical way than is presently being done, and at a larger scale.

The operator is looking at a number of areas including the Dogger Bank in a radical bid to deliver large scale wind energy while circumventing regulation and opposition to offshore wind by siting the development further out at sea.

TenneT recently shared early findings of a study that said its plan could be billions of euros cheaper than conventional windfarms and international power cables. The power hub would send electricity over a long-distance cable to the UK and Netherlands, and possibly later to Belgium, Germany, and Denmark.
Rob van der Hage, who manages TenneT’s offshore wind grid development programme, told the Guardian, “It’s crucial for industry to continue with the cost reduction path. The big challenge we are facing towards 2030 and 2050 is onshore wind is hampered by local opposition and nearshore is nearly full. It’s logical we are looking at areas further offshore.”

As each further mile out to sea means another mile of expensive cabling to get the power back to land, the firm argues a more innovative approach is needed.

The island idea would theoretically solve that by allowing economies of scale, higher wind speeds and mean relatively short, affordable cables taking power from offshore turbines to the island.

There, converters will change it from alternating current – as used in mains electricity but which incurs losses of power over long distances – to direct current for transmitting back to the UK or Netherlands.

That long distance cable, an interconnector, would give the windfarms flexibility to supply whichever country’s market was paying the most for power at any given time, and mean the power almost always had a use.

The island is envisaged to be around 5-6 square kilometres and Tennet would cover the estimated €1.5bn (£1.31bn) cost of building the hub at the project’s heart.

Next steps, once development of the island is achieved would involve securing European power generator investment and a roadmap to completion by 2027.

TenneT thinks the project could handle windfarms with a capacity of 30 GW, more than twice today’s total installed offshore wind power across the whole of Europe.

National Grid described it as offering an “innovative design that could play an important role in the long term”.