An industrial consortium launched preparations on Monday for a possible future power grid under the Mediterranean that would carry solar energy from Africa to Europe.

The Transgreen group hopes that solar power farms planned in the Sahara desert will generate 20 gigawatts of electricity by 2020, and that a quarter of this could be fed into the European market.

For this to happen, undersea cables will have to be laid, a project that experts estimate could cost up to eight billion euros (10 billion dollars).

As of Monday's launch, the group has assigned only two million to three million euros to promote the technology and to study the feasibility of the plan.

"These energy highways are absolutely essential," said France's environment minister Jean-Louis Borloo at the launch, underlining that European consumers could help offset the cost of North Africa's energy development.

French-based energy giant EDF will lead the consortium, supported by a dozen more major firms including France's Areva and Alstom, Spain's Abengoa and RED Electrica and Germany's Siemens.

The group's office will be operational by the end of the year.

Transgreen's energy transport grid is to be developed in parallel with the Desertec project, a German-led plan to build a vast network of wind and sun farms across North Africa and the Middle East.

Promoters hope this will provide the region with cheap, clean power and leave enough spare to be exported to Europe and cover 15 percent of its needs.