Marokane, who previously held senior Eskom positions, including as its head of group capital, will rejoin no later than March 31 of next year, Public Enterprises Minister Pravin Gordhan said in a statement.
Marokane has been acting-CEO of sugar producer Tongaat Hulett since the end of February.
Bloomberg News reported on Thursday that Marokane was expected to be appointed as Eskom CEO.
Eskom has been without a permanent CEO since February when then-CEO Andre de Ruyter left with immediate effect and its Chief Financial Officer Calib Cassim took over in an interim capacity.
The debt-laden company has struggled to keep the lights on in Africa's most industrialised economy for more than a decade. But this year power outages have been particularly bad, leaving households and businesses in the dark for up to 10 hours a day.
"He will hit the ground running. That is what Eskom and South Africa need right now," the chairman of Eskom's board of directors, Mteto Nyati, said in a statement issued by the utility.
In a separate statement on Friday, Gordhan announced the appointment of Tsepo Monaheng as the new CEO of state-owned defence company Denel.
(Additional reporting by Tannur AndersEditing by Alexander Winning and Louise Heavens)
By Bhargav Acharya