Eskom said on Wednesday electricity tariffs will have to rise significantly over the next five years for the company to cover its debt.
The power utility was briefing Members of Parliament (MPs) on Tuesday on its Build Programme which will cost several billion Rand.
Eskom's Finance Director Paul O'Flaherty said consumers were spared when this year's tariff increase was lowered.
He said this was unlikely to be the case going forward.
“When we reduced the tariff this year from 25,9 to 16 percent, it meant that government’s reserves, that would have been in Eskom, were sacrificed. That R8 billion will be exhausted over the next year.”
Eskom also confirmed it had secured more than three quarters of the funding for the Kusile Power station.
The power utility assured MPs the Build Programme was on track after funding problems delayed the project.
Eskom are planning to add 10,000 megawatts of power to the grid through two new coal fired power stations, Medupi and Kusile.
O'Flaherty confirmed he did everything in his power to assure MPs that delays in Eskom's Build Programme were adequately dealt with.
Medupi's first unit will come on line in 2013, with the next unit following six to nine months later.
Kusile will start adding power to the grid by December 2014.
O'Flaherty said they have secured 77 percent of the funding to complete Kusile and have already identified where the rest of the money for the R120 billion project will come from.