In September 1996, he joined
Eskom as an engineer-in-training at the
Duvha Power Station in
Witbank, Mpumalanga. In 2004, he moved to Eskom headquarters, becoming senior manager for
power plant engineering in the enterprises division. The details of the ensuing internal inquiry, which was led by
Dentons, were not made public, but Koko was reinstated. In late October 2015, newly appointed Eskom CEO
Brian Molefe announced that Koko had been appointed as group executive for
generation at Eskom. Koko was viewed as "pro-nuclear". Also during this period, Koko's generation division came under scrutiny for controversial
coal procurement deals that were alleged to favour the politically connected
Gupta family. In October 2016, the
Public Protector,
Thuli Madonsela, published a report on
state capture entitled
State of Capture, which identified the coal deals as potentially unlawful and corrupt. Under his leadership, Eskom issued requests for proposals in its bid to procure 9.6
gigawatts of nuclear power. However, Koko was replaced as acting CEO in mid-2017 when he was subject to internal disciplinary charges. The charges arose from revelations that his stepdaughter's company had done over
R1 billion in business with Eskom. The disciplinary inquiry exonerated Koko, and he returned to work on 8 January 2018, though he was not returned as acting CEO; instead, he returned to his permanent position as head of generation. The
National Union of Metalworkers of South Africa said that the disciplinary process was "a mockery and an insult to all those who believe in good corporate governance" and that by reinstating Koko, "The Eskom board is clearly showing the people of South Africa
the middle finger". Through January, Koko faced mounting pressure to resign from Eskom, and at the end of the month, a newly appointed Eskom board announced that it had given Koko an ultimatum, telling him that he would be fired if he did not resign within 24 hours. However, Koko lodged an urgent application in the
Labour Court of South Africa, seeking to block his dismissal. Eskom promptly reversed itself, withdrawing the ultimatum and instead instituting fresh disciplinary charges against him. Two of the new charges related to Eskom's Trillian–McKinsey deal, and the other two charges related to Koko's personal dealings with the Gupta family. Koko was suspended again pending the conclusion of the new disciplinary inquiry. The new disciplinary tribunal met only once before, on 14 February 2018, President
Jacob Zuma resigned from office; within two days, Koko had tendered his own resignation from Eskom. == Corruption charges: 2022–2024 ==