SA electricity supply still under pressure

Submitted by: Margaret McKenzie, Monday, February 6, 2012

South Africa’s electricity supply is still under pressure.  Brian Dames, the Eskom CEO, has indicated that a 3,000 MW savings is required to allow for a reliable power system in South Africa. At the most recent Eskom Power System briefing on 30th January 2012, Dames highlighted that the core problem faced by Eskom was the need to tackle the maintenance backlog at Eskom Power Stations.


According to the Eskom Integrated Report 2011, Eskom power stations had a maximum capacity of 41, 194 MW.  The graph below contrasts Eskom capacity available versus peak demand for the week starting 23rd January 2012.  The graph illustrates that actual capacity achieved never exceeded 33,500 MW and so is currently falling well below maximum potential capacity of Eskom power stations.   This is because Eskom’s supply capacity varies from day to day depending on factors such as planned maintenance of power stations, unplanned outages and electricity available for purchase from others.

Eskom is experiencing supply constraints in the current period for two main reasons.  Firstly since electricity demand is lower in the summer season, Eskom has scheduled more maintenance take place in the current period in order to help address the backlog.   Secondly, because of the maintenance backlog the scale of unplanned outages is higher than normal.   As a result of these factors Eskom has been forced to make more use than usual of its open cycle gas turbines which are more costly to run than other generation methods.

Eskom has estimated that the winter peak demand for 2012 will be 37,500 MW which is higher than the capacity levels that Eskom is currently achieving.   During the winter period Eskom will reduce planned maintenance in order to increase available capacity.   However, because of the maintenance backlog Eskom may continue to experience unplanned outages that are larger than anticipated leading to continued risk of demand outstripping capacity.

Margaret McKenzie