January 2008 won’t be repeated but still tough times ahead
IN JANUARY 2008 heavy rain fell on coal mines and coal-powered stations in Mpumulanga, causing a massive power blackout that shut down a good part of South Africa’s economy, including its gold mines. The rain has begun falling again and there have been flood warnings. Will we see a similar blackout now? The answer is no. And there are three important reasons why. However, we do suffer from an acute shortage of generating capacity and over the next two years there will be loadshedding.
SA gets 92% of its electricity from coal and most of that comes from power stations in Mpumulanga, where, in January 2008, the rain flooded opencast coal mines and turned the low stockpiles at power stations into slush. The slush blocked up the mills and nozzles at the stations and shut them down. The first reason for this not happening again, is that SA now has much better stockpiles.
In 2008 – for idiotic financial and ideological reasons – Eskom had reduced the
Eskom’s senior management is much improved since 2008. Instead of dreamers who denied problems, Eskom now has practical men facing problems head-on
stockpiles to a few days. Moreover, the coal was of uncertain quality. Current stockpiles average 41 days and there’s been a major effort to obtain more reliable supplies. Rain is always a problem, but with decent stockpiles you can draw the drier coal from the top and greatly reduce its effect. If the mine is flooded, the power station still has over a month of supply.
The second reason is that Eskom has built up its emergency capacity. When Eskom finally realised it had run out of power, it built the quickest, cheapest units it could, which are gas turbines. (“Gas turbine” refers to the thermodynamic cycle rather than the fuel. These machines are like jet engines and can run on paraffin, gas or diesel.) They were built in the Western Cape at Atlantis and Mossel Bay. They have low capital costs but extremely high fuel costs, using diesel. Eskom avoids running them when possible. However, they have a combined capacity of 2 100MW (Koeberg’s capacity is 1 800MW) and are very reliable. They’re there if we need them.
The third reason is that Eskom’s senior management is much improved since 2008. Instead of dreamers who denied problems, Eskom now has practical men facing problems head-on. Nonetheless, the problem of supply remains grave. Eskom’s maximum demand in 2010 was 36 664MW and its
capacity is around 41 000MW. That gives it a reserve margin of 11% – below the 15% required. Furthermore, that capacity includes pumped storage, hydro, gas turbines and some rickety old coal-powered stations, none of which can provide reliable baseload power.
If SA’s economy grows at a modest 3%, electricity demand will do the same – which means we’ll need 1 100MW of new capacity every year. But the earliest we can expect a new power unit producing is in December next year from the Medupi coalpowered station, which will have six units of 800MW each built at intervals of eight months. Kusile, the second new coal-fired power station (the same size) will follow just over a year later.
Before that and after that there’s nothing, apart from a pumped storage scheme of 1 332MW and a wind farm of 50MW.
Wind turbines are essentially useless as their power is so unreliable. In Britain – with better wind conditions than SA – their plentiful wind turbines failed to provide electricity when it was most needed, in the bitter cold of this winter. Indeed, some of them – cold and still, generating nothing – actually consumed electricity to heat them to prevent them freezing. However, politics and ideology will probably force SA to build these extremely expensive white elephants.
Meanwhile, in the real world of electricity supply, Unit 1 at Koeberg nuclear power station is out of action due to a minor but unfortunate mishap. The unit was down for a refuelling outage and a modification to its low pressure turbines (which will give it an extra 32MW of free power). When it came up again, the radiation detectors spotted a leaking fuel element. Such leaks happen from time to time with old fuel, rather like tube leaks on an old boiler.
However, this was with new fuel and it looks like a manufacturing fault from the supplier. No doubt Eskom will have something to say to them. Replacing a leaking element is routine but time-consuming and the unit will not be up and running before the last week of January.
After the world financial crisis of 2008, SA’s economy is recovering and electricity demand has returned to that before the crisis. Eskom is feeling the strain. There isn’t going to be a repeat of the fiasco of January 2008 but there are tough times ahead.
KOEBERG NUCLEAR POWER STATION