In contrast country to officials in many other European Union countries, Bulgarian authorities want to strengthen the country's economic and political ties with Russia. And the view toward Russia of many Bulgarians is strongly positive.

A number of EU member countries have started to diversify their energy supplies, particularly gas deliveries. In this regard, Bulgaria too will be a part of the western-bound Trans Adriatic Pipeline project, which would carry Azeri natural gas to Europe. The pipeline's construction is expected to begin in 2016. 

However, experts do not regard this as an effort by Bulgaria to limit its relations with Russia and turn its back to the South Stream project, which is currently frozen by the EU.

Energy experts think Bulgaria might be divided over South Stream and the Trans Adriatic Pipeline.

South Stream is a planned gas pipeline to transport Russian natural gas through the Black Sea to Bulgaria and through Serbia, Hungary, Slovenia and on to Austria.

The Trans Adriatic Pipeline, viewed as a way for Europe to rely less on natural gas from Russia, will run from the border between Turkey and Greece, near Kipoi. From there it will cross Greece, Albania and the Adriatic Sea before terminating in Italy. 

Amanda Paul, a policy analyst and senior program executive with the Brussels-based think tank European Policy Centre, said that economic and political relations between Sofia, the Bulgarian capital, and Moscow are excellent, even though Bulgaria regards Germany "as its main strategic partner."

"While Bulgaria is also looking at ways to diversify its energy routes, Russia/Gazprom will continue to be considered a key partner," Paul said. "In fact there is an old saying in Bulgaria, which is, 'Always with Germany, never against Russia.'" 

"Compared to some other member states, Bulgaria is not overly concerned over its reliance on Russian gas, and it is happy to do more business with Moscow, which will bring significant investment and employment opportunities to the country," she said.

Paul said the Trans Adriatic Pipeline is unlikely to bring the same opportunities as South Stream and it will take years for it to be an alternative for gas diversification as it will not be operational until 2018.

She also argued that the low amount of gas that will come from Azerbaijan through the pipeline will prevent it from becoming a viable option for Bulgaria. 

"Bulgaria’s main energy partner will remain Russia, which will continue to have a largest market share," said Paul. "Despite the close ties of some export companies to Gazprom it does not mean that Russia has a veto on Bulgaria looking at other routes, and options for its energy needs. After all Russia needs all the friends it can get in Europe, particularly nowadays." 

But she said that, despite warm relations with Russia, Bulgaria should not put all its eggs in one basket.

Kostadin Sirleshtov, head of Sofia branch of the U.K.-based private international law consulting firm CMS, said that Bulgaria will also be different politically from its fellow EU countries. 

"The dependence on Russian imports makes Bulgarian political circles reluctant to join the countries from the EU with a much a firmer approach," he said. "I am not expecting for this situation to change." 

He said the Trans Adriatic Pipeline was a good opportunity for Bulgaria in terms of providing a different gas supply and better prices. However, he added, "The public perception in Bulgaria is somewhat mixed and definitely we enjoy a bigger support towards Russia than the average EU member state."

The former director of the Vienna-based international energy policy organization Energy Community, Slavtcho Neykov, said Russia should be regarded as a great partner in energy sector. 

"The economic developments in general are intensively dependent particularly on relations with Russia. It is not an enemy," said Neykov. "The Bulgarian authorities do not oppose South Stream. Bulgaria is one part of it."

"Decreasing the dependence is desirable," Neykov said. "But the reality should recall that such a decrease might take years before it is a fact. At this stage, the relevance of Trans Adriatic Pipeline project to Bulgaria is more theoretical than practical."

Neykov said it is hard to see the pipeline project as an alternative for gas deliveries to Bulgaria. 

"Nevertheless, theoretically, it will be great if Bulgaria can rely on some quantities, but for this, interconnections are needed in the first place -- and their construction should be based on economic justification."

The South Stream pipeline project is aimed at transporting 63 billion cubic metres of gas per year under the Black Sea through Bulgaria to central and southern Europe via Ukraine by 2018. The project is currently blocked by EU due to the ongoing crisis in Ukraine.