This flexible DC network would be made possible by digitally controlled, high-voltage DC power converters, a technology that has been entering the market over the past five years. The key, says ABB project manager Lars Stendius, is the newer technology's ability to reverse a line's current without changing the "polarity" of its voltage.

Veal says the ambitious project would take five years to build and construction could start as soon as 2010. At the moment, Airtricity is looking for partners to help finance it, including transmission players who could profit from the proposed energy trading.

Hydropower could play a key role, too. Gregor Czisch, an energy systems modeling expert at the University of Kassel in Germany, says the benefits of a European supergrid linking Mediterranean and North Sea wind farms with Norway's immense hydropower reservoirs would be "considerable." Those reservoirs could be tapped during periods of low wind, providing a renewable backup to the wind power.

But, to Czisch, solidifying the European grid is just a first step. His optimization studies show that the benefits of the supergrid multiply if one extends high-voltage DC lines beyond Europe to North Africa and the Middle East. By doing so, he says, one could ensure that there was always enough output from renewable sources, such as wind plants and solar panels, to power an area spanning 50 countries and 1.1 billion people.

In Czisch's visionary scenarios, wind power alone provides 70 percent of the region's total power, thanks largely to excellent wind resources in Egypt and Morocco that flow more powerfully and more consistently than Europe's. And it's affordable: including the power lines, Czisch estimates that under his scheme electricity consumed in Europe (including the African wind power) would cost about 4.6 eurocents per kilowatt-hour -- about the same as the European average. "It's no more expensive than our existing power supply, with no fossil fuels and no nuclear," he says.

The challenge is to get the supergrid onto the policy agenda. Because it's a big-energy concept, Czisch says, it runs counter to the thinking of many renewable energy advocates, who he believes prefer to see renewable energy as local energy sources, such as solar panels on rooftops. "You would have to build huge high-voltage DC lines, huge wind-power plants in Morocco, and so on. This is something that could easily be done by the big utilities -- but the utilities are the enemy of the renewables people," he says.

Airtricity's Veal is hoping to get some help from the European Commission, which just released a proposal for an integrated European energy policy. "We're not going to solve all of the EC's problems," Veal says, "but we can be a major contributor."

Peter Fairley is a TR contributing writer based in Paris.