Four countries are considering a plan to lay the world’s longest undersea power line between wind farms in the Caspian Sea and southeast Europe.

Azerbaijan, Georgia, Bulgaria and Romania discussed the idea for a “Green Energy Corridor” at a meeting in Budapest.

The idea is to turn the Caspian into southern Europe’s equivalent of the North Sea, and give central and southeastern regions of Europe cheaper energy.

Hungary’s foreign minister Peter Szijjarto said on his Facebook page that the aim was to meet the region’s growing demand for electricity in a way that was “environmentally friendly and as cheap as possible”.

The 1,100km-long line would come ashore in Azerbaijan, go through Georgia, and then go under the Black Sea to Bulgaria and Romania.

It could cost around €10bn.

The partner countries have set up a joint venture, based in Bucharest, to act as the owner of the project. It will now commission a feasibility study, which may be completed by the end of June.

As well as the high-voltage direct current line, a fibre-optic cable may also be laid.

Azerbaijan’s energy minister Parviz Shahbazov Ogtay said around 4GW of energy could be transmitted in the first phase.

“We also intend to implement similar projects with our partners in Central Asia, such as Kazakhstan and Uzbekistan, which are also keen to join, so we can bring in additional energy sources,” he said.

Bulgaria is contributing to the project with energy storage facilities.

Zhecho Stankov, the country’s energy minister, said it was developing three pumped-storage plants to help balance the intermittent wind generation on the Caspian. It is also developing a 9GWh battery storage system with financial support from the European Commission.