Hellenic gas transmission system operator DESFA said Thursday it will sign May 15 a basic cooperation agreement with Russia's OAO Gazprom (GAZP.RS) on the construction of the South Stream natural gas pipeline.

Hellenic gas transmission system operator DESFA said Thursday it will sign May 15 a basic cooperation agreement with Russia's OAO Gazprom (GAZP.RS) on the construction of the South Stream natural gas pipeline.

For this purpose DESFA and Gazprom have formed a 50-50 joint venture with a rolling annual presidency, DESFA said in a statement.

DESFA said the Greek section of the pipeline will be completed by September 2009 at the latest, while the total pipeline will be completed by mid 2010.

It also said the final investment proposal for the project will be ready by mid 2011, adding that financing agreements for the project will be completed after that date. The pipeline will begin operation by the end of 2015, according to DESFA.

The point of entry to the Greek section of the pipeline - with a capacity of 10 billion cubic meters a year - will be the Greek-Bulgarian border while the exit point will be determined by a feasibility study and the joint working group, DESFA said, without disclosing further details.

The South Stream pipeline will transport 31 bcm of Russian natural gas a year under the Black Sea.