The offer, named "Energy 160" to honour the 160-year-long history of the Italian company, includes both gas and electricity supplies.

Poste, now a conglomerate whose services range from digital payments to mobile services, said in May it would enter the energy sector by the end of the year, with an offer based exclusively on renewable sources.

Poste Italiane aims to be among the top five energy providers in Italy by 2024, the company said in March.

(Reporting by Francesco Zecchini; Editing by Keith Weir)