Stage 16 load shedding on the cards

More stages of load shedding are on the cards even as South Africans are still in the dark about the government’s plans to resolve the energy crisis.

MORE stages of load shedding are on the cards even as South Africans are still in the dark about the government’s plans to resolve the energy crisis.

The National Energy Regulator of South Africa (Nersa) has mooted eight more stages of load shedding, with the worst-case scenario a total shutdown at Stage 16.

Nationwide power cuts returned with a vengeance after a December holiday break and the new stages, although not yet implemented, are contained in Nersa’s Code of Practice for Real-time Emergency Load Reduction and Restoration of Supply After A Major System Incident.

“Stage 16 schedules shall consist of all 16 blocks off simultaneously. All the load will be continuously off. Stage 16 is a controlled shutdown of the system at the customer end,” it reads.

Although public comment closed towards the end of last year, Nersa this week said it had noted media request for further information and would revert in due course.

“The code addresses not only the power system requirement (the load reduction required) but how this is done and communicated to have the least negative impact on critical infrastructure. Requirements for extreme power system constraints and blackout restoration have also been included in the form of essential load requirements,” according to the document.

It further states that while the code provided for an ordered and consistent approach to emergency load reduction, it did not interchange any actions that the system operator may deem necessary in real time to ensure the security of the national power system (in terms of its compliance to the grid code, among others, to prevent a national blackout).

“This includes the requirement for the system operator to prudently manage system operating reserves.”

In the code titled “strictly controlled distribution”, Nersa said that restoring power to all customers after a significant system incident or blackout could take days to weeks.

The order in which the supply was restored to individual customers was often dictated by the nature of the incident, and the ability to restore supply to essential loads as quickly as possible should form part of the restoration regime.

“The risk of a national blackout, while inherent to the operation of a large power system, has a low likelihood of materialising given operating protocols and protection systems in place.

“However, should a national blackout materialise, the impact on the country would be severe, impacting critical sectors of society and the economy, including personal and occupational safety, water supply and sewage systems, telecommunications and transport, and even national security.”

Water, economic and political experts canvassed this week agreed that a total grid shutdown was highly unlikely.

Water scientist Dr Anthony Turton said that while reaching Stage 16 was “airy fairy”, it was a consistent stay of around Stage 6 that he was most concerned about, not from a water quality perspective, but in terms of national security.

“Most of your battery back-up systems are not designed to store enough energy for longer than Sstage 6. So wherever you have current resilience, it starts to fall away; things like your ATM machines, your retail malls and hospitals,” he said.

“All of the major urban areas rely heavily on internal water storage capacity to sustain the delivery of services within their footprint. Once you start going to Stage 6 load shedding, there is not enough internal storage capacity in the reservoirs and in the water towers.

“There, very rapidly, you start to see large communities drying up and the projection we made was that drying up was likely to start rioting, social unrest and upheaval,” said Turton.

In the Nersa document, which makes provision for Stage 16, it states that even under healthy system conditions a robust set of emergency load reduction protocols was needed.

“A sequence of unexpected events or a large significant event in an otherwise healthy power system can give rise to the need for emergency load reduction.

“It should also be noted that emergency load reduction is not only required under generation capacity shortages but could also arise due to regional or local transmission or distribution network constraints,” according to the document.

While economist Dawie Roodt believes that reaching the highest stage of load shedding was most unlikely, he said Nersa was wasting its time.

“Because the whole electricity sector is so volatile and so unpredictable, and there are so many other uncertainties, it doesn’t really make much sense to set all these rules if you don’t have a Minister of Energy Affairs that does what he is supposed to be doing.

“Nersa is also wasting its time when it determines electricity prices every year, because nobody knows what the right price of electricity should be. Eskom asks for X percent and Nersa always gives X percent. The whole industry is a major mess (and) we actually need to start all over again,” Roodt added.

The Nersa provisional code states that Eskom’s sheddable load should be divided into 16 blocks all as close to the same size as possible and arranged to follow each other on a 24-hour rotation.

It says that in Stage 1 each block would be shed for two hours. The code explains that in Stage 2 each block is shed again within the 32-hour period, “reasonably separated from the time they were shed in Stage 1”.

In Stage 4, each block is shed for a fourth time within the 32-hour period. From Stage 5 the pattern changes and one of every four blocks is shed for an additional two hours. This means that a two-hour slot becomes a four-hour slot.

In Stage 8, all the blocks are shed for four hours at a time and in the next stage, one of those blocks gets a six-hour outage. By Stage 12 all the blocks will be shed for six hours at a time, while Stage 14 will see two blocks with eight-hour cuts while the others have six-hour cuts with no power provided before the next load-shedding period.

“Stage 15 schedules shall be the same as Stage 12 with the exception that three blocks shed under Stage 13, 14 and 15 are shed for an additional two hours (eg six-hour time slots become eight-hour slots), with no power provided before the next load-shedding period.

“Stage 16 schedules shall consist of all 16 blocks off simultaneously. All the load will be continuously off. Stage 16 is a controlled shutdown of the system at the customer end,” the document said.

Turton said the government was aware of the implications of load shedding on national security which is why it promulgated policy on water shifting.

“Because the real purpose of water shifting was to ensure that the little bit of water left behind would still end up in somebody’s tap somewhere simply to prevent the social unrest which was likely to occur at Stage 6 and beyond,” he said.

Provided by SyndiGate Media Inc. (Syndigate.info).