MADRID (AP) — The leaders of France, Portugal and Spain said on Oct. 20 that they have agreed to substitute a proposed gas pipeline connection between Iberia and France with an undersea “green energy corridor” that would eventually transport hydrogen.

Spanish Prime Minister Pedro Sánchez said the plan was to connect Iberia to France and the European energy market by means of a pipeline from Barcelona in Spain across the Mediterranean Sea to Marseille in France. He said it could be used to transport natural gas temporarily, before it starts carrying hydrogen.

Sánchez made the announcement after the leaders of the three countries met in Brussels where they are attending an European Union summit.

No timeline or cost estimate were announced.

Speaking upon his arrival at the European Council headquarters, French President Emmanuel Macron said the scheme was aimed at opening up the Iberian Peninsula by developing a “green energy corridor between Portugal-Spain and France, and through France the rest of Europe.”

He said the three countries will work on intensifying their electrical interconnections. Macron said the project could also add electricity interconnections.

Spain and Portugal had been pushing for the Midcat natural gas pipeline connection across the Pyrenees mountains with promises that it would be used for green hydrogen in the future. But France opposed that plan saying it was too costly, would take too long to build and was not the solution to Europe’s energy problems.

Check out a recent episode of the Factor This! podcast that examined the future of green hydrogen, featuring experts from Generate Capital, EDP Renewables, and the National Renewable Energy Laboratory. Subscribe today wherever you get your podcasts.