Still, political challenges remain. Kjaer points to a set of wind farms for Kriegers Flak, a shallow sandbar in the Baltic where the territorial waters of Denmark, Sweden, and Germany converge. Each country plans to build three of the world’s largest offshore wind farms–up to 640 megawatts each, about the size of a medium-size coal plant–within a few miles of each other, yet without coordinated transmission. “They are talking about taking one grid into Sweden, and one into Germany, and then you have the Danes,” says Kjaer. “It makes no sense.”
A coordinated link, Kjaer says, would cost less to build than three separate lines, and would provide considerable extra value by linking Northern Germany’s variable wind-power production with Sweden’s hydropower riches. Germany could export excess wind power to Sweden via a Kriegers Flak interconnection when it has more than it can absorb, then import hydropower from Sweden when the wind dies down. The EC has appointed a mediator–as it did for the French-Spanish interconnection–to work on the issue.
Such efforts could pave the way to an entirely fossil-free power supply in Europe, much as Al Gore has proposed for the United States. Modeling by Gregor Czisch, an energy consultant in Kassel, Germany, shows that in theory, Europe and North Africa can source all of their electricity from renewable sources using a supergrid with conventional HVDC lines that can shift power thousands of miles with minimal losses. In this vision, wind power provides 70 percent of Europe and North Africa’s energy needs, and Scandinavian hydropower serves as the backup battery, while African solar farms and distributed biomass-fueled power plants play supporting roles.
Notably missing from the supergrid vision? A role for the conventional power plants that provide most of today’s power. “The utilities are thinking about the supergrid,” says Czisch, “but not too fast.” Czisch says that the utilities prefer a short-term approach to transmission planning that is more protective of their existing investments, whereas the public needs a bold new approach to planning at a European or at least regional level: “We really need an independent organization which can do the calculations necessary.”