After months of speculation and delays, Andre de Ruyter was on Monday named as chief executive officer of debt-crippled state power utility Eskom, surprising investors with an unexpected choice and angering a key union.

De Ruyter, 51, has considerable corporate experience in the country, though not at state-owned companies. His appointment comes at a time when Eskom is undergoing a transformation that will require technical and financial knowledge as well as an ability to deal with the government and labour unions.

The appointee, currently CEO of packaging firm Nampak, will take up the post on January 15, the Department of Public Enterprises said in a statement Monday. The state-owned power company has been looking for a new CEO since Phakamani Hadebe in July became the 10th person to vacate the post in as many years.

"The market is going to have to know him better and understand what qualities he is to bring to the table," said Jones Gondo, a credit research analyst at Nedbank in Johannesburg.

"The market had not anticipated him to be one of the slated candidates. At least now we can possibly move on to the substantive issues."

Fixing Eskom is about more than South Africa - African Development Bank

"His lack of experience at Eskom itself puts him on a steep learning curve, while the absence of political allegiances means he is unlikely to be expected to fight any of the tough political battles the position also demands," Jonker said in a reply to questions. "It is clear that the Ramaphosa administration wants AdR to focus on management, not politics."