One option is to start off with the low-cost ITGI pipeline plan, estimated to cost €2.5 billion compared to Nabucco's €7.9 billion price tag, and then expand at a later date, one industry source told the Reuters news agency on condition of anonymity.
That implies downscaling the project - with only a low level of gas imports at the beginning - but the parties are also mulling ways to increase the size of a planned pipeline across Turkey and then share it, to keep costs down.
The project might be launched in two phases: 'Southern Corridor Phase I' would carry gas to Greece and onwards to Italy; then later, 'Southern Corridor Phase II' would create a spur from the main pipeline and follow Nabucco's original planned route northwards to Austria, an industry source said.
A senior executive at ITGI shareholder Edison suggested on Tuesday that his project might be able to work together with Nabucco, but did not give precise details.
The Trans-Adriatic Pipeline (TAP), the lowest cost option at 1.5 billion euros, is not currently involved in any possible Nabucco merger scenarios, industry sources quoted by Reuters said.
On the record
Asked by EurActiv to comment, a European Commission spokesperson admitted that the EU executive had advised the different players competing under the brand name 'Southern Gas Corridor' to "explore options for beneficial cooperation".
"The Commission would welcome any cooperation which contributes to the achievement of the objectives of the Southern Gas Corridor […] Energy Commissioner [Günther] Oettinger has been encouraging existing Southern Gas Corridor projects for stronger cooperation," the spokesperson said.
But Nabucco spokesperson Chistian Dolezal denied that any discussions between Nabucco and ITGI about any potential cooperation had ever taken place within the consortium.
"Nabucco is being developed as a stand-alone pipeline and will be a crucial link between the Caspian region and Middle East region and Europe," Dolezal said.
EurActiv spoke to representatives of ITGI, but they declined to comment publicly.
A spokeswoman for the Trans-Adriatic Pipeline (TAP), a 10-20bcm project in the Southern Gas Corridor that somewhat resembles ITGI, said that the project had always been open to cooperation and it would welcome additional shareholders. Any cooperation would have to be commercially realistic, she added.
Moreover, any decision on selling an initial 10 billion cubic metres of Azeri gas to European companies would ultimately be taken by the Shah Deniz consortium, which owns the gas, she insisted.
Statoil and BP operate the Shah Deniz gas field in Azerbaijan and are the largest shareholders in the Shah Deniz consortium, each holding 25.5%. TAP's shareholders are Statoil of Norway, EGL of Switzerland and E.ON Ruhrgas of Germany.
The consortium’s decision will primarily be based on tariffs and the technical viability of the project, and this is where the TAP project would appear to be stronger than its competitors when viewed on a level playing field, the TAP spokeswoman added.