Eskom suddenly announced on Thursday evening that it will implement stage 2 loadshedding from 22:00 this evening until 05:00 on Friday morning.
This was because on Thursday it lost three additional generation units and had to use its emergency reserves in order to meet demand throughout the day.
The emergency demands, therefore, became critically low.
On Wednesday Eskom warned that the power system continued to remain "severely constrained and vulnerable" and that the possibility of loadshedding remained.
Fin24 reported earlier that, after some of Eskom's generating units failed over the weekend, power supply was running dangerously low by Wednesday morning.
Unplanned outages above 9 500 MW mean Eskom has to resort to emergency power generation by using open cycle gas turbines and pumped-storage hydroelectric plants.
These are very expensive ways of generating power, particularly the gas turbines, which require large quantities of diesel.
Find your loadshedding schedule here.