This followed an announcement on Tuesday that the Industrial Development Corporation (IDC) was also to become a 12,5% stakeholder.
Both bodies have made it clear that their commitment to the project is dependent on a number of conditions being met.
"During its recent meeting held on July 24 2003, the board of Eskom approved a 12,5% equity investment in the proposed 2,2bn Coega aluminium smelter project in the Eastern Cape," Eskom announced.
"The board approval is subject to the overall terms and conditions of Eskom's participation."
Coega Development Corporation spokesman Raymond Hartle said that he was very happy about the announcements that had been made by Eskom and the IDC.
"The milestones that were set out a year ago are being achieved that augurs very well for the finalisation of the investment in the smelter by Pechiney."
The French group, which is the target for a hostile takeover by Alcan of Canada, plans to take 49% of the equity in the smelter project.
Although there are concerns that the takeover bid may delay the project, the consensus is that it would not derail the investment.

