Under the terms of agreement, KKR will invest in Acciona Energía International (AEI), the international renewable energy generation business of Acciona Energía, which will retain a two-thirds stake in the unit.

KKR will pay €417m for a one-third stake in the AEI and will also help to fund future growth of the renewables portfolio.

KKR co-chairman and co-CEO Henry Kravis said, "I am really optimistic about the opportunity to partner with such a prominent renewable energy company and to help further develop what is already one of the largest operating renewable portfolios in the world."

AEI holds renewable energy assets comprising 2.3GW in 14 countries outside Spain, including the US, Mexico, Australia, Italy, Portugal and South Africa.

Acciona chairman and CEO José Manuel Entrecanales Domecq said, "Our strategic alliance will broaden our international reach, and it will transform the scale of what we can achieve."

The investment is expected to provide an implied enterprise value €2.6bn, including €1.3bn in equity and €1.3bn in net debt, to AIE while the transaction scheduled to be completed before the end of 2014.

In addition to operating AEI’s assets for 20 years under a management agreement, Acciona Energía will provide a right of first offer to AEI on future renewable energy projects it develops within AEI’s operational territory.