Is loadshedding imminent? – Ask the weatherman

July 18th, 2019, Published in Articles: Energize

We should be grateful we’re having a mild winter. Without the power received from the independently owned and operated renewable energy-sourced power stations we’d be in the dark – or facing serious loadshedding events right now.

Roger Lilley

Since we are not experiencing loadshedding at present,  some may believe that Eskom’s power stations are on the mend – especially with the utility announcing that another unit at Medupi Power Station has come online, adding about 4800 MW of capacity to the grid.

But actually, what’s keeping the lights on is the mild winter. Eskom’s electricity generation supply is far lower this year than it was last winter, and consistently falls short of demand. Without additional supply from non-Eskom sources, the load would have to be curtailed. That curtailment is achieved through the process we call loadshedding.

According to the power utility’s website, during the period between 3 June to 7 July, demand frequently exceeded supply. A low point occurred on Friday 21 June when total output from Eskom’s power stations fell to below 25% lower than load. Eskom’s output fell below load demand by over 10% twice in the same period: On Wednesday 26 June and again on the following Monday 1 July. Not only was there no reserve power – the reserve power was in negative territory. The utility’s output was particularly low during the first seven days of July with load exceeding supply (see Fig. 1).

Eskom reports the load, which means it was not curtailed, so the shortfall must have been met by South African independent power producers and imported power from Mozambique. We have no other source of electricity.

Yet, the state-owned power utility and certain individuals both within and without the organisation, as well as some in government, continue to state that the country does need independent power producers.

To make matters worse, the country is in the grip of a serious economic downturn, so demand is lower than it would be if the economy were in a better state.

Fig. 1: Eskom’s electricity generation (blue line) vs. the load on the grid (orange line) (source: Eskom).

The big question is this: Since Eskom cannot supply sufficient electricity while the economy is in the doldrums, how will it meet demand should the economy recover? Or will Eskom prove those right who say that it is the biggest hinderance to economic growth?

Electricity consumers in South Africa should expect and make provision for further loadshedding. Furthermore, users should endeavour to save electricity wherever possible. This can be best be done by deliberately initiating an energy efficiency programme at home and at work.

Eskom’s new tariffs came into effect recently, resulting in higher electricity costs. By using less electricity, consumers can cushion the increase to some degree. But this also works against Eskom’s recovery. As more consumers of electricity reduce demand, Eskom will receive less income. Ultimately, the utility is at the mercy of those who choose to defect from the grid, either totally or partially, and those who use alternative sources of energy.

Figs. 2 and 3, taken directly from Eskom’s website, show the true state of affairs.

Fig. 2: Week-on-week comparison of energy sent out by Eskom (2018 vs. 2019) (Source: Eskom).

Fig. 3: Week-on-week comparison of peak demand (2018 vs. 2019) (Source: Eskom).

Loadshedding is instituted by the power utility’s national control centre to keep load and generation balanced. Without this intervention, South Africa’s electrical system could face a total collapse. We are so close to a collapse that all we need for loadshedding to be re-instituted is a week of very cold weather.

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