REW has an article on a new proposal for a north sea supergrid - Stakeholders Team Up To Expand Europe's Super-Grid.
Europe has plenty of grid initiatives to help meets its ambitious goals for reducing greenhouse gas emissions with the help of renewable energies, such as wind and solar. Now it just needs an action plan. All the talk over the years about building new long-distance high-voltage transmission infrastructure to span national territories has, for the most part, remained just that.

But experts say the talk has now advanced to a new level, especially in the area of offshore infrastructure in northern Europe where around 100 gigawatts (GW) of offshore wind power are planned.

Indicative of the growing momentum, yet another initiative recently entered the fray: the Friends of the Super-Grid. The group consists of established players in the energy logistics chain, including Areva of France, Prysmian of Italy, and Mainstream Renewable Power of Ireland as well as Germany’s Siemens and Hochtief. It has proposed a “phase one” project to connect England, Scotland, Germany and Norway at a cost estimated of around €34 billion.

That amount is close to the €30 billion projected by the North Sea Countries Offshore Grid Initiative. That group, which launched at the end of last year, consists of the European Union member states Germany, France, Belgium, Luxembourg, the Netherlands, Sweden, Denmark, Ireland and the United Kingdom as well as Norway, which is not part of the EU. Its goal is to spur construction of an offshore grid in the North Sea with connecting installations on the mainland. The countries hope to sign a memorandum of Understanding (MoU) later this year and lay the foundation for action. ...

Greenpeace has looked at the costs of building high-voltage, long-distance onshore and offshore grids across Europe. The organization estimates that 34 existing high-voltage alternating current (HVAC) interconnections will need to be upgraded between neighboring countries at a cost of about €3 billion. At least another 17 high-voltage direct current (HVDC) interconnections will need to be installed for about €16 billion. And up to 11 new long-distance HVDC super-grid connections will be required for around €100 billion. The International Energy Agency (IEA), looking at only an upgrade of existing transmission assets in Europe, estimates investment of about € 200 billion through 2030.