The so-called Energy Community Treaty extends European Union guidelines for electricity and natural gas to Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Macedonia, Romania and Serbia and Montenegro, aiming to create a common market operating in line with the bloc's energy regulations.
"The (non-member) countries going early for energy reforms will benefit more," said EU energy commissioner Andris Piebalgs. "With this treaty all the countries are making the same effort at the same time... and by opening up markets it (the treaty) will attract investments."
Turkey, a major energy hub in the area through which several oil and natural gas pipelines feed the European markets, has yet to sign the treaty pending outstanding talks with the EU, Piebalgs said.
"We are in the process of clarifying some issues. I expect after we have solved them, Turkey will join this treaty," he said.
The treaty, which still needs to be ratified separately on national levels, binds countries to adopt EU energy rules, open up energy markets and set EU environmental standards. It is expected to generate over 21 billion euros ($25.10 billion) in investments in the coming 15 years, officials said.