EGP, a subsidiary of Italian utility Enel, said an IPO was likely to occur in October. It is also studying a possible listing of its shares in Madrid.
Parent company Enel has said it expects to raise about €4billion from the sale of a minority stake.
The IPO would rank as the biggest in the European renewables market since Spanish utility Iberdrola listed a stake in its Iberdrola Renovables unit in 2007.
As Enel filed for a market listing, however, it said it would continue to consider the private placement of a minority stake with long-term investors, either to supplement or form an alternative to the IPO.
At end-2009, EGP boasted total installed capacity of 5.7GW, including 2.3GW from wind farms, 2.5GW from small-scale hydroelectric power, 700MW from geothermal power and 200MW from other sources like solar and biomass. The group has a presence in 17 countries.