MILAN, June 21 (Reuters) - Swiss asset manager Energy Infrastructure Partners (EIP) is one of the investors in talks with Eni over the possibility of buying a minority stake in the energy group's low-carbon unit Plenitude, two sources with knowledge of the matter said.

Eni, which had to freeze the initial public offering of Plenitude last year due to adverse market conditions, still aims to list it. The sale of a stake in the subsidiary would give a value to it, making a future listing smoother, the sources said.

Eni and EIP declined to comment.

Last week three separate sources had told Reuters Eni was intensifying talks with several potential investors over Plenitude, without naming any partners.

Eni's renewable and retail unit could be valued at more than 6 billion euros ($6.6 billion) in a private transaction, one of the sources had said.

Eni is working on the sale of between 5% and 15% of Plenitude and could even do a deal before August, they had said.

In February Norway private equity firm HitecVision engaged in talks with Eni over the acquisition of a minority stake in the subsidiary but a deal has not materialised.

To develop Plenitude and its other subsidiaries, the Italian group is applying a 'satellite' approach that aims to create independent units specialising in specific activities, able to attract investors focused on those businesses.

Plenitude generates power from renewables, sells electricity, gas and energy services to households and businesses, and is developing a network of charging points for electric vehicles. ($1 = 0.9161 euros) (Reporting by Francesca Landini; additional reporting by Ron Bousso in London Editing by Keith Weir)