Building an offshore grid in the North Sea can boost Europe’s energy independence, while lowering costs and reducing the environmental impact. But it won’t be easy
The Russian invasion of Ukraine has fuelled the urgency of energy transition ambitions. For the UK and EU, offshore wind turbines could propel their advances – but only if grid innovation keeps pace.
The UK wants to generate 40GW of offshore wind by 2030. The recent ScotWind seabed leasing round awarded a record-breaking 25GW of potential projects, enough to power about 1.5 million homes, setting the country on a path to meeting this target. The EU is targeting at least 60GW by 2030 and 300GW by 2050.
But while offshore wind technology costs are falling rapidly, grid innovation must keep up, or we risk missing these targets. Studies show that when offshore wind power assets are built at the scale planned, single point-to-point connections from offshore wind farms to the onshore grid (as is currently standard) will be inefficient, more expensive, and less environmentally friendly.
What does integration mean? One idea is for a multi-country connected offshore meshed grid in the North Sea, built using novel technology. This would enable much higher levels of energy to be transported with lower losses. Crucially, supply would be more easily shifted to meet demand across the five major European offshore wind players – the UK, Belgium, the Netherlands, Germany and Denmark.
There are already a growing number of point-to-point interconnectors transporting energy from one European country to another – the UK currently has four. However, a meshed offshore grid would be like “the London to Brighton main line” says Fay Lelliott, a global practice leader for power transmission and distribution at Mott MacDonald, a consultancy firm.
“It’s not only point-to-point; it’s possible to travel from London to Brighton by lots of different routes,” she explains.
Dr Cornelis A. Plet is a principal consultant at DNV, who coordinated the PROMOTioN Horizon 2020 project to advance the development of high-voltage direct-current (HVDC) meshed offshore grids. He explains what integration means in practice. “It’s two lines coming together at the same location, rather than having two separate links with their own converter stations.” Combining them can save hundreds of millions of euros, he says, “and doing this consistently across the North Sea lowers costs significantly.”
UK electricity system operator National Grid ESO has determined that taking an “integrated approach” for wind farms delivered from 2025 could save consumers approximately £6bn in capital and operating expenditure between now and 2050, with cables and onshore landing points reduced by around 50%. It is developing a Holistic Network Design (HND) due in June that is expected to incorporate some of these learnings and recommend how to facilitate the 2030 target, including 11GW from ScotWind.