State-owned power utility Eskom has once again declared an emergency and has alerted its key industrial customers that they should reduce their load by a minimum of 10% in line with regulatory protocols.

The February 20 declaration is the first of 2014, with the utility having made a similar intervention in November last year. That intervention led to an outcry from the mining and industrial sectors, which were already under strain as a result of rising power and other input costs, as well as industrial relations volatility that had resulted in production cuts.

The latest declaration was made the day after Eskom revealed that the power system was severely constrained, owing to the high levels of unplanned outages and the fact that a number of units were down for planned maintenance.

In a statement Eskom said it was following the protocol in terms of its emergency procedures in order to secure the power system.

"We have alerted our key industrial customers and have required them to reduce their load by a minimum of 10% as from 14:00 today. The emergency is in force until 21:00 tonight. This will be reviewed thereafter to determine the way forward."

It also called on commercial and residential customers to assist by switching off geysers, adjusting air-conditioning temperature levels to 23⁰C and turning off lights and nonessential appliances from 17:00 to 21:00.

Every effort, it said, was being made to avoid load shedding.

The summer months in South Africa were especially susceptible to supply-side disruptions, as the utility conducted the bulk of its maintenance in the run-up to the high-demand winter months.

Eskom indicated that the situation would remain critical until at least 21:00, but expected some reprieve as demand fell in the run-up to, and during, the weekend.

The utility had continually warned that the system would remain under strain until new capacity was introduced from the Medupi, Kusile and Ingula power projects.

The first 800 MW Medupi unit was scheduled to be synchronised to the grid in the second half of 2014.

But concerns had been raised that there could be yet more delays as the strike-prone site moves towards the demobilisation of a number of its workers.