Last month, the European Commission (EC) called for construction of regional electric transmission connections across the North Sea, around the Baltic region, and around the Mediterranean Sea, to distribute solar and wind power to and across Europe. It's all part of a plan to boost renewable energy from 8.5 percent of European energy consumption to 20 percent by 2020--and even more thereafter.

But the EC, the European Union's executive body, acknowledges that getting these so-called supergrids built will mean forging new agreements between European countries for transmission planning and investment--much as the United States needs more cooperation between states to, for example, move wind power from the Midwest to major cities. "The wind power which consumers demand cannot be delivered without new networks," the EC report says, and "there is little strategic planning" between nations to build the required connections.

However, several recent developments suggest that progress on transmission between European nations is possible. This summer, for example, a negotiator appointed by the EC convinced France to accept a new transmission connection with Spain, breaking a 15-year impasse over expanding power exchanges between the countries. Use of high-voltage DC (HVDC) technology will enable planners to bury the new line and thereby overcome local opposition to conventional overhead AC transmission lines.

The French-Spanish connection will help both countries balance power supply and consumption--especially Spain, which struggles at times to accommodate its installations of highly variable wind power, the largest in Europe. EC negotiator Mario Monti estimated that the link, called an interconnection, would reduce reliance on the countries' least efficient power plants, thus avoiding 1.5 million tons per year of carbon-dioxide emissions (roughly the annual emissions of 600,000 cars).

Christian Kjaer, CEO of the European Wind Energy Association, a Brussels-based trade group, calls it a "major breakthrough" that shows how Europe can overcome entrenched opposition to such interconnections. "It's a good example of why we need more than a national approach," says Kjaer.

Meanwhile, proposals for HVDC grids to deliver clean power from offshore wind farms to European consumers are getting more detailed. In September, for example, Brussels-based environmental consulting firm 3E mapped out a blueprint for what a North Sea offshore wind-power grid might look like. In 3E's design, 3,500 miles of underwater HVDC cables crisscross the North Sea, forming a network capable of hooking up 68,000 megawatts' worth of new offshore wind farms--enough generating capacity to meet 13 percent of the region's power consumption.