The Nabucco gas pipeline venture delayed the start of construction even as the World Bank, the European Bank for Reconstruction and Development and the European Investment Bank said they may lend the project as much as 4 billion euros ($5.2 billion).

“Construction will start 2012,” Nabucco Gas Pipeline International GmbH Managing Director Reinhard Mitschek said at a briefing today in Brussels. “The operation of the pipeline will start 2015.” The Vienna-based venture had previously said that construction was set to begin in late 2011, with shipments starting at the end of 2014 or early 2015.

The 7.9 billion-euro pipeline is designed to carry gas more than 3,300 kilometers (2,050 miles) from Turkey to Austria to reduce European dependence on Russia. The venture is counting on gas from the Caspian region and Iraq to fill the link.

“We have to synchronize Nabucco first to the gas supply sources,” Mitschek said. Once the gas supply has been secured, the “open season” tender process for transporting gas will begin by the end of the year or in the first quarter of next year, he said.

Financing will be completed in the second half of 2011, Bloomberg Businessweek reported.