Plans to build “energy islands” in the North Sea to act as hubs for offshore wind farm converters, interconnectors and green-hydrogen production have moved a step closer to reality after the North Sea Wind Power Hub (NSWPH) announced that initial assessments shows the project is technically and economically feasible.
The NSWPH consortium — consisting of Danish and Dutch/German transmission system operators Eneginet and TenneT, Dutch gas network operator Gasunie and the Port of Rotterdam — says it now plans to push forward with its “hub-and-spoke” concept, in which several “islands” would be built. The consortium has not yet specified an exact number, but it suggests a gradual roll-out of 10-15GW hubs with power-to-gas facilities that would become operational in the 2030s.
These could be artificial sand-based islands, or monopile- or suction-bucket-based platforms (like existing converter stations) or built on caissons — the kind of watertight retaining structures used to repair bridge foundations. It would depend on the location — the water depth and the seabed — as to which would be most appropriate, NWSPH tells Recharge.
A single offshore island was never considered, because “one island would mean too many wind farms 'surrounding' the island 'catching' wind from each other [and] lowering the efficiency”, said NWSPH. “Also, the distances from those wind farms to the island hub would be so large that additional 'halfway' substations would be needed, causing unwelcome cost-increasing effects.”
The hub-and-spoke approach could see 180GW of offshore wind installed in the North Sea by 2045, but would require international and national cooperation.
“While it is likely possible to build a first hub-and-spoke project within the current regulatory framework and market design, that is, current EU and national legislation, significant changes are required in national practices, approaches, planning and policies in order to allow for integrated infrastructure projects such as the modular hub concept being part of the long term energy transition,” said NWSPH.
The consortium is asking the Danish, Dutch and German governments and the European Commission to consider setting up a consultation process.
“The North Sea Wind Power Hub consortium is in contact with the UK as well as Norwegian organisations. No UK or Norwegian organisations are part of the consortium right now, but we would certainly want to cooperate with them. A first hub project does not need necessarily five countries. It could also be initiated by, for example, three countries,” NWSPH tells Recharge.
The European Commission is also drawing up its own plans for a “meshed super-grid” in the North Sea, known as PROMOTioN (Progress on Meshed HVDC Offshore Transmission Networks), which has brought together 33 companies and organisations from 11 countries.
Updates include new quotes from NSWPH and clarifications on the number of hubs, the type of island to be selected and the role of the UK and Norway in the project.