European governments are keen to bring Azeri gas to their markets, and ease current domination by Russia.
Kjetil Tungland, TAP's Managing Director, argued the venture would also spur other badly-needed growth-boosting projects in Greece.
"Projects like TAP signal confidence for other investors," he said.
The TAP route would connect with a pipeline in Turkey and cover 478 kilometers (297.03 miles) in Greece, 209 kilometers (129.87 miles) in Albania, and include a 105-kilometer (65-miles) undersea section before reaching southern Italy. It would run as deep as 810 meters (2,650 feet) below the surface of the Adriatic Sea.The Nabucco pipeline, which would only run across land, would extend for 1,300 kilometers (808 miles).