Singh defended his decisions on billions of rand that were allegedly illegally paid to the Guptas.
On the eve of his appearance before Parliament, Eskom announced that Singh had resigned.
He had been suspended in September last year, pending an inquiry.
Yesterday Eskom spokesperson Khulu Phasiwe announced that Eskom’s head of group capital Krish Govender had also tendered his resignation with immediate effect.
In Parliament Singh faced tough questions over why Eskom reduced the fine from R2.1billion to R577million for a mine, giving the Guptas a guarantee of R1.6bn and signing off on R400m on the Chinese deal.
Despite admitting to travelling to Dubai several times, Singh denied meeting the Guptas there for business purposes.
He said he had met Tony Gupta coincidentally at the luxurious Oberoi Hotel.
Singh also denied that the Guptas paid for his trips despite evidence leader, advocate Ntuthuzelo Vanara, producing an invoice that Sahara Computers covered his travel costs for the trips to Dubai.
Singh had insisted his associate in the United Arab Emirates (UAE) had paid for the trips.
He defended the decision of Eskom to reduce the fine of Optimum mine from R2.1bn to R577m.
Eskom had issued the fine to Glencore before the Guptas bought it, but after the family purchased the mine it reduced it.
“I was aware of the R2.1bn fine. In terms of my understanding the penalty was subjected to another Treasury process to allow that R577m was paid,” he said.
“It is my understanding that R2.1bn was not cast in stone,” said Singh.
He also defended the decision to give a guarantee of R1.6bn to Tegeta, a Gupta-owned company.
This was to allow Tegeta to deliver coal because of an emergency situation.
“With R1.6bn there was a settlement of liabilities. That is what we alluded to - that the R1.6bn would settle liabilities and the mine is a going concern,” said Singh.
He confirmed there were no minutes or records of this decision, and the decision was not approved by the board of Eskom.
He said the decision fell within Eskom’s treasury division.
Eskom’s former chief financial officer also confirmed that the power utility did not have a contract with Trillian, but with global consultancy firm McKinsey.
McKinsey was paid R1bn for its work at Eskom and Trillian R500m.
Eskom has taken the matter to court, demanding the money back.
The Asset Forfeiture Unit last week began to attach some of the assets of the companies to recover the R1.6bn.
This is part of the multiple investigations by the AFU to recoup billions of rand from the state capture project in the state-owned entities.