A team of renewables heavyweights led by industry veteran Eddie O’Connor is pushing for a new grid infrastructure to link Europe’s wind and solar resource centers.
The group, working for an Irish company called SuperNode, is looking to develop superconducting cable systems that will be able to collect offshore wind efficiently and export it to load centers across Europe.
The offshore cable platforms, referred to as SuperNodes, will act as power collection stations for multiple wind farms. They will increase the voltage of power and convert it to direct current so it can be transmitted efficiently over long distances, acting like routers on a large meshed grid.
Existing voltage source converter technology can handle up to 900 megawatts of offshore wind power on a single 800-million-euro ($949 million) platform.
High-voltage direct-current (HVDC) converters can be configured to handle more power but are constrained by the capacity of today’s export cables.
SuperNode aims to overcome this with cryogenically cooled superconducting cables that can handle vastly increased currents compared to conventional HVDC technology.
A key benefit of the concept is that it would cut the cost of offshore wind by reducing the number of transmission links to land, said O’Connor, the co-founder and chairman of Irish renewables developer Mainstream Renewable Power, in an interview.
Cooled cables could halve offshore wind transmission costs
The way European offshore transmission owner projects are developed at present leads to links springing out from land “like the spines of a porcupine,” O’Connor said. “All your reinforcement has to be on land.”
This arrangement is too inefficient and costly for Europe to achieve its decarbonization targets, he argues. Using cryogenics to cool SuperNode cabling would help cut the cost of links in half, he said.
According to a SuperNode presentation shared with GTM, using current technology, a 24-gigawatt offshore wind cluster would need more than 32,000 kilometers of cabling, resulting in a total project cost of some €44.4 billion ($52.7 billion), or €14 ($17) per megawatt-hour.
SuperNode expects to cut this to around 3,520 kilometers of cabling, equal to €20.5 billion, or €6.50 per megawatt-hour.
O’Connor and the rest of the SuperNode team, which includes former President of the European Parliament Pat Cox and ex-EirGrid Director of Grid Development John Fitzgerald, hope to have eight SuperNodes installed off the U.K. coast by 2040.
This would grow to 17 by 2050 and would potentially link to other areas of high offshore wind resources across Europe, as well as connecting with solar production in the south of the continent.
“What we would do is exploit the North Sea, the Atlantic of Ireland, the Baltic, the Bay of Biscay and areas of strong wind south of Marseille,” O’Connor said.
This grand vision builds on a previous idea of O’Connor’s: to build a supergrid across Europe. The concept was taken up by an industrial interconnection alliance called Friends of the Supergrid, which rebranded as Friends of Sustainable Grids last year.
Legacy cables tie policymakers hands
Despite years of lobbying, a European supergrid remains a far-off prospect. And Daniel Atzori, a research partner at the energy consultancy Cornwall Insight, said the SuperNode idea might also be hard to get off the ground.
"The advantages of the SuperNode are that it adopts a holistic, pan-European and collective approach to the electrification of the continent,” he said in a statement.
The benefits of a SuperNode network would be akin to those claimed for energy islands, which are already being planned by European grid operators such as TenneT and Energinet, but could extend across all of Europe, Atzori said.
However, “the sheer cost, difficulty, policy challenges and time scale of deploying a mass network of new transmission lines across Europe makes it unlikely," he added.
"It is hard to see how the existing network issues wouldn't be better tackled by targeted reinforcement of existing transmission networks — possibly with HVDC links between trouble spots, as Germany is doing — and adding interconnectors."
Another challenge for the concept, he said, is that many of the issues with higher electricity consumption would likely occur at a lower level in distribution networks, which a SuperNode program might draw money away from.
“While it would doubtless be better to plan the European transmission system using this technology and rebuild from scratch, it doesn't seem entirely realistic given the billions of euros' [worth] of existing infrastructure that has already been built," Atzori said.
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