Decline in plant at Eskom may set future trend
Eskom would be unable to meet the electricity needs of the country over the next five years unless it could improve the performance of its plants, the company said on Tuesday. To meet the projected demand, Eskom needs an average of 75% of its plants available to dispatch electricity over a year. In the industry this is called the energy availability factor (EAF). Engineer and publisher Chris Yelland said that while there was generally a decline in EAF going into summer as more units were taken down for routine maintenance, “this year’s [seasonal] decline is much bigger”.
Eskom would be unable to meet the electricity needs of the country over the next five years unless it could improve the performance of its plants, the company said in response to questions on Tuesday.
To meet the projected demand for electricity, Eskom needs an average of 75% of its plants available to dispatch electricity over a year. In the industry this is called the energy availability factor (EAF).
However, plants can be out of service due to planned maintenance or unplanned outages. The EAF for the year so far is 73% — a significant decline on 2017’s 79% — and has fallen alarmingly in recent weeks to below 70%. The trend indicates that the average for the year is likely to fall further.
The trend has energy experts concerned, and they fear a return to earlier years when Eskom was unable to meet demand and resorted to load shedding in 2008 to avoid crashing the system.
Engineer and publisher Chris Yelland said that while there was generally a decline in EAF going into summer as more units were taken down for routine maintenance, “this year’s [seasonal] decline is much bigger. What is really disturbing is that it is going down very fast.”
Eskom said that the decline was due in part to planned maintenance “but also to unplanned events”, such as the explosion at Lethabo power station in the Free State in early October, taking an entire unit out of service.
Eskom acknowledged, however, that the present performance of the plant would not be sufficient for the future. In a statutory document called the “Medium-term System Adequacy Outlook”, which it published at the end of October, it projected that in scenarios of low and moderate demand an energy availability factor of 75% was needed. If this was not achieved, Eskom would have to resort to other options for generation or have to cut demand, implying load shedding.
“It is thus important that the EAF is improved to and maintained at a minimum of 75%. If this is not achieved, additional supply and/or demand side levers will be required. This could include the restarting of expensive units currently placed in reserve storage, increased open-cycle gas turbine usage and accelerated demand reduction initiatives. The large amount of maintenance under way is intended to increase EAF to higher than 75%,” Eskom said in a statement.
But commentators are concerned that Eskom’s plants are deteriorating due to age and neglect and the downward trend is more likely to continue than change direction.
“The midlife refurbishment of these plants has been deferred and that has implications.
“We are seeing the consequence of running them on and on,” Yelland pointed out.
Eskom says that coal stockpiles, which have run dangerously low over the past several months, are expected to recover from December as new coal contracts have been concluded, two of them in the past month.
“Excluding the two stations under construction [Medupi and Kusile], total stockpile level is 25.2 days. Coal stockpile days at nine power stations are below the requirement of 20 days,” Eskom said.
ADDITIONAL LEVERS WILL BE REQUIRED. THIS COULD INCLUDE THE RESTARTING OF EXPENSIVE UNITS CURRENTLY PLACED IN RESERVE STORAGE
REFURBISHMENT OF THESE PLANTS HAS BEEN DEFERRED. WE ARE SEEING THE CONSEQUENCE OF RUNNING THEM ON AND ON