Bulgaria's parliament adopted on Friday changes to the country's energy strategy, mandating gas transmission system operator Bulgartransgaz to start work, by the end of the year, on expanding the gas infrastructure system from the border with Turkey to the border with Serbia. After a final decision on the investment project has been made, Bulgartransgaz will launch a public procurement procedure with an estimated value of 2.29 billion levs ($1.3 billion/1.2 billion euro), VAT excluded, for making the necessary expansions of Bulgaria's gas infrastructure system, according to the updated energy strategy published on the website of the parliament. Works under the contract must be completed by the end of 2019. The final investment decision depends on successful signing of binding capacity allocation agreements under an Open Season procedure. Bulgaria's government has received an official notification from Russia's Gazprom for participation in the market test, which practically means that the section of the TurkStream pipeline for transit of Russian natural gas to Europe will cross Bulgaria, Sofia-based media quoted Bulgarian energy minister Temenuzhka Petkova as saying in parliament on Friday.