Eskom says it's been forced to over-utilise some gas turbines that require diesel.
South Africans may have to brace themselves for more load shedding later this week.
Load shedding is when there is not enough electricity available to meet the demand from all Eskom customers.
In addition to load shedding, Eskom now faces a problem of people not being able to access the schedules.
Eskom warned of 12 more hours of load shedding and rain could further strain the already fragile power grid.
Eskom says it's working to build up more power reserves by today to minimise disruptions for Monday.