A judicial commission of inquiry should be set up to investigate allegations that Eskom did not act upon reports warning it of an impending energy crisis, the Democratic Alliance said on Saturday.

"President Jacob Zuma must appoint a judicial commission of inquiry to investigate why the CEO of Eskom, Jacob Maroga, ignored a series of confidential internal memos that showed Eskom's internal practices were precipitating an energy crisis in South Africa," DA Shadow Energy Minister Sejamothopo Motau said in a statement.

He said the inquiry should also determine and reveal others who might have known about the memorandums.

On Friday, Maroga told reporters that Eskom was aware of weaknesses in its coal contracts before it received a report warning it about its stockpiles.

Maroga was responding to allegations in energy consultant Susan Olsen's report of July 2007 which had been handed by the DA to Parliament's portfolio committee on energy.

Olsen is a partner at Wingfield Consultancy, a well-known oil and coal research group in Boston, Massachusetts. Her report deals with irregularities in the supply of coal to Eskom.

Maroga acknowledged receiving the damning report from Olsen, but said that had not been the first time Eskom became aware of the challenges around coal.

He had passed the report on to two managers.

'Vulnerability of our system'

According to Maroga, Eskom began seeing challenges in supplying power in 2005 when one of Koeberg's units failed.

"This illustrated the vulnerability of our system," he told a press briefing on Friday, adding that Eskom knew then there were reserve margin problems at national level.

He said coal challenges revolved around both pricing and logistics.

In late 2007, however, load shedding had occurred, largely as a result of generation plant shortage and performance, and then coal prices and availability became a problem.

Maroga acknowledged that around the time of the January 2008 energy crisis in the country there had been low coal stockpiles and problems with wet coal. As a result, he had made leadership changes in Eskom's primary energy division.

"I created two new positions. We now have 40 days of coal stockpiled and we haven't had load shedding since April 2008."

After load shedding on 24 January 2008, Eskom had gone through a recovery process, "but we have not fully recovered from issues relating to primary energy".

Eskom was exposed to various risks regarding coal ? such as road transport of coal in Mpumalanga.

At present the system was still under pressure and Maroga admitted that if the economy was to stage a quick recovery, risks would deepen.

Addressing Olsen's allegation that Eskom appeared to be entirely incapable of managing the procurement of coal, Brian Dames, chief officer generation, said Eskom was working hard on cost aspects of coal.

Mining companies 'supportive'

"We have engaged with the mining companies, they have been very supportive. We want longer-term contracts and a better quality of coal."

Dames said coal transport by road was not sustainable and Eskom had to consider how it could engage players like Transnet.

The restructuring of the primary energy team was ongoing.

Dames explained that in the long-term the country didn't have enough mines to supply Eskom.

"The coal is there, it's just a matter of getting it out of the ground."

On Saturday, the DA's Motau said former President Thabo Mbeki, former Minister of Minerals and Energy Buyelwa Sonjica, and former Public Enterprises Minister Alec Erwin should all be called before an inquiry.

"All three of these people need to account for their role in this debacle," he said.

"To date not a single person has been fired, sanctioned, suspended or even publicly reprimanded for mismanagement in a scandal that literally left South Africa without electricity."

Motau said he would write to the Public Protector on Monday to ask for an urgent investigation into the matter.

He alleged that Olsen "had her contract with Eskom terminated days after the memo was sent."