The European Union's executive has unveiled a vast plan to merge the EU's 28 national energy markets with the aim of providing cheaper energy for consumers and weaning Europe off Russian gas supplies.

European Commission vice president Maros Sefcovic today called it "undoubtedly the most ambitious energy project" since the inception of the EU over half a century ago.

He believes that a well-connected European energy grid could save businesses and consumers up to €40 billion euro a year.

Europe imports 40 per cent of its natural gas from Russia, half of that via pipelines through Ukraine, and it could to take years of investment to reduce that dependency.

The proposals will be debated by EU environment ministers on March 6.