Why Eskom keeps getting accused of lying about load-shedding

3 years ago 1

ARTICLE AD BOX

Power utility Eskom keeps getting called out for lying about load-shedding severity because it cannot report load curtailment statistics separately.

Every few months, energy experts and South Africans on Twitter accuse the utility of implementing a higher stage of load-shedding than it has announced, particularly during the evening peak demand periods.

There have been several days on which Eskom’s evening peak demand statistics showed it exceeded the maximum capacity it can load-shed under a declared stage.

A recent example of this was on Thursday, 4 May 2023, when Eskom was implementing stage 6 load-shedding. Stage 6 allows for shedding up to 6,000MW of capacity nationally.

However, Eskom’s evening peak statistics for that day showed “load-shedding” of 6,303MW at the point of highest demand in the evening.

Taken at face value, that would imply it had implemented stage 7 load-shedding, without any official announcement.

Eskom added a short explanation for exceeding 6,000MW in brackets behind the number, stating it comprised stage 6 load-and stage 1 & 2 load curtailment.

Evening Peak 04/05/2023 (18:19)

Eskom Availability 26 613MW
Loadshedding: 6 303 MW ( LS stage6 & LC stage1&2)
Total demand: 31 836 MW
———————————
-Number of OCGT’s and GT’s Utilised: 5
-Renewable Gen: 750 MW
-IPP Availability (Dispatchable): 1 014 MW
-RES: Wind 649 MW, CSP 101…

— Eskom Hld SOC Ltd (@Eskom_SA) May 5, 2023

Load curtailment is a mechanism that allows Eskom to ask its heaviest energy users — like smelters — to reduce their electricity demand to help alleviate pressure on the grid.

In return for their participation, these customers are compensated financially by Eskom and can be exempted from national stage 1 and stage 2 load-shedding.

It would seem that a simple solution for Eskom to reduce public confusion about its load-shedding stages would be to report national load-shedding and specific customer load curtailment separately.

However, Eskom told MyBroadband that doing so would be complex, as the evening peak demand statistics it declares are largely developed from historical — and not real-time — demand.

“The measurement of actual individual demand reduction is challenging — even more so if it is required to split into shedding and curtailment,” Eskom stated.

“However, at a national level, Eskom uses statistical methods to derive how much total demand was reduced from the power system.”

“Therefore, the two categories of load reduction are reported in totality.”

Unlike during load-shedding, the actual reduction in load due to curtailment varied based on factors like time of day, day of the week, and whether it is a high or low-demand electricity season, Eskom explained.

“Load curtailment differs from load shedding in that during a load curtailment event, the customer is required to operate at the reduced level for the full duration of the event, whereas load shedding customers are rotated.”

Instead of curtailing customer demand by a set amount of megawatts, Eskom implements curtailment on a proportional basis.

The load curtailment stages require the customers to shed the following amounts of capacity from their normal demand:

Stage 1 and stage 2 load curtailment (combined) — 10%
Stage 3 load curtailment — 15%
Stage 4 load curtailment — 20%

There appears to have been an increase in the amount of load curtailment Eskom has implemented recently.

However, Eskom would not give specific details about increases in the number of customers that have signed up for the load curtailment programme.

The utility said its key industrial customers have been on load curtailment since the introduction of the mechanism.

“In the recent past, some of the smaller customers have requested curtailment,” Eskom said.

“Customers who meet the requirements of curtailment and can be isolated on the network, have been allowed to curtail their load.”

Among the industries that have shown interest in load curtailment is agriculture, which is particularly vulnerable to power outages.

Agri Northern Cape’s Nicol Jansen recently told RSG that farmers did not have enough power-on time during the current severe levels of load-shedding to irrigate crops.