The appointment was announced on Monday by Minister of Public Enterprises Pravin Gordhan.
Mabuza will take-over from Phakamani Hadebe as acting CEO on 31 July, the statement said.
Hadebe resigned in May as efforts to turn-around the debt-stricken energy company floundered.
Over the next three months, Eskom’s board of directors will continue the hunt for a permanent CEO, the statement added.
The announcement comes the day before Eskom is due to publish its financial results on Tuesday, where they are expected to register record-breaking losses.
Mabuza is a businessman, investor and influential figure in South Africa. He was appointed chairman of Eskom by South Africa President Cyril Ramaphosa in January 2018.
Eskom under fire again
Eskom was already in the spotlight earlier on Monday after the country’s controversial anti-graft ombudsman, Public Protector Busisiwe Mkhwebane, launched a probe into deals with 27 independent power producers, South African media reports.
The probe accuses Eskom executives of awarding electricity production licenses to private companies without observing due process, the online publication says. Under the contracts the indebted firm is saddled with an additional $150m ( R21 billion) in annual losses, the publication says.
The allegations come as the government has already pledged around $4.25bn in taxpayer funds over the next two years to help Eskom pay off its $30bn state-guaranteed debt.
On Sunday, Eskom spokesperson Dikatso Mothae said they had received the letter from the Public Protector and would cooperate with the probe.
The case is the latest in a spate of actions launched by the Public Protector. On Monday, Mkhwebane’s case to enforce disciplinary action against Pravin Gordhan, a key ally of President Ramaphosa, was suspended by the High Court.
The ruling is the second time in a week that a judgment has gone against Mkhwebane, in what critics say is a blow to her credibility. South Africa’s Constitutional Court ruled on July 22nd that Mkhwebane had acted in bad faith when investigating an apartheid-era bank bailout.
In a separate case, President Ramaphosa says he will urgently challenge Mkhwebane’s finding that he misled Parliament over a 2017 campaign donation.
Dark days continue
Last year, President Cyril Ramaphosa vowed to “unbundle” debt-laden Eskom by splitting it into three entities, and slimming down its bloated workforce, which a former Eskom chairman claims is 40% overstaffed.
Yet so far a plan to restructure the company has not materialised.
The government pledged $1.6m (23 billion rand) in February to bailout the firm over three years. This figure was topped up on 22 July as the government announced an additional $4.2bn in bailout funds over the next two years to service Eskom’s debt and keep the lights on in the country.