South Africa’s government will retain a controlling stake in struggling state utility Eskom, Finance Minister Nhlanhla Nene said on Monday, adding that power shortages were the biggest risk facing Africa’s most developed economy.

Nene said the key to resolving the crisis at Eskom was intervening to contain costs.

Eskom’s funding gap to 2018 is estimated at 200 billion rand ($17 billion), while it expects to receive 23 billion rand from the government this year as it battles to keep the lights on.

The Treasury said last week it was asked by a government-appointed commission to consider a proposal to partially privatise Eskom or sell some of its assets in order to secure further funding to expand generating capacity.

Separately, Nene said crucial public sector wage talks with unions were making good progress.

About 1.3 million teachers, police officers and health workers will vote this week on the government’s offer of an inflation-linked wage increase.