Running on the spot

A year after Eskom completes the construction of the last of its new power stations in 2019, it will start decommissioning some of its oldest generating units. That will reduce the reserve, or spare generating margin, to below the desired 15% level, necessitating more generation investment sooner than it otherwise would have needed. The average age of the utility’s existing 22 power stations is 30 years, with the oldest being 51 years.

“By 2020 we’ll start decommissioning at least 10 000 MW of power plants because they will have reached the end of their lifespan,” says Eskom CEO Brian Dames. To provide context, the Medupi and Kusile stations will have a combined generating capacity of 9 600 MW when complete in 2019. They’re being built at a cost of R210bn.

A coal-fired power station’s lifespan is about 40 years. But Eskom had to mothball some of its power stations in the 1980s as it had excess generating capacity. When it became clear that more generating capacity was needed in the late 1990s, the company brought those mothballed stations back into service, at a cost of R19,6bn. The last mothballed unit will be brought back online by March 2014.

The 1 000 MW Komati power station in Mpumalanga — one of Eskom’s oldest coal power stations — will be one of the first stations that will be decommissioned, and possibly dismantled come 2020.

The 10 000 MW that must be decommissioned as a result of ageing plants will almost take out the equivalent of the entire 11 256 MW that Eskom is currently installing.

Dames says this means the country cannot sit back and think the urgency for more infrastructure investment will be over after the current construction round. “We will still not be completely safe after Kusile,” says Dames.