The new financing, provided through the Clean Technology Fund (CTF), complements a $260-million loan granted by the bank last year for Sere and Upington.
Some of the money is also earmarked for the 100MW Upington solar power project.
Earlier Eskom had secured further loans of $100 million from CTF and $265 million from the African Development Bank to fund the two projects, and $151 million from the French development agency for Sere alone.
Eskom has launched a pre-qualification process for turbine supply and installation. It hopes to start construction early next year.
South Africa has under 10MW turning to date.