The European Union is to provide €578 million to build a power link between Spain and France to carry excess Spanish renewable energy and release one of Europe's worst network bottlenecks.

The EU aims for each member state to reach at least a 10 percent interconnection level. Spain is currently at six, according to Commission figures.

Why is this news?

Because the grant is such a big one. It will be the EU's largest-ever grant for energy infrastructure.

Construction of the 370-kilometre Franco-Spanish subsea power cable across the Bay of Biscay will nearly double current power exchange capacity to 5,000 megawatt.

Why is the European Commission doing this?

The Commission wants to ease the uptake of renewable energy in both countries, reduce the continent's dependence on Russian gas and help meet its climate goals.

Officials say the project will help to "end the isolation of the Iberian Peninsula" — long a bugbear of Spanish energy executives who complain of France's reluctance to boost cross-border links.

The EU's long view — the free flow of cheap energy

The investment is part of a pot of €873 million that EU nations agreed to invest in 17 energy infrastructure projects towards the goal of a single energy union in which power and gas would flow freely and be cheaper.

It comes out of an EU fund known as the Connecting Europe Facility, or CEF.

Other projects include:

€70 million for construction of the SuedOstLink to transport northern wind power to the south of Germany

€101 million to introduce natural gas to Cyprus

€3.7 million to study a potential gas link between Malta and Italy

Brussels is drafting new renewable energy targets to help meet its climate pledge to cut emissions 40 percent by 2030.

A Commission report is said to suggest the share of renewable in energy consumption reached 17 percent in the bloc in 2016.

The EU has set itself a goal of 20 percent by 2020 — although each member state has its own national target based on its own economy's potential.

Have any states reached their targets yet?

Yes. Eleven are already at their 2020 target. The Netherlands, France, Ireland, Britain and Luxembourg are furthest away from their goals, according to the Commission report.

What they are saying

"Only a fully-interconnected market will improve Europe's security of supply, ending the dependence of single suppliers and give consumers more choice," said Europe's Climate Commissioner Miguel Arias Canete.