South Africa now has 16 stages of load shedding
The national energy regulator Nersa has published the approved the NRS 048-9 Code of Practice Edition 3 – the latest document governing how load shedding is implemented in South Africa.
The NRS 048-9 Code of Practice is primarily an electricity utility-driven and executed document that derives its mandate and authority, once approved by the National Energy Regulator of South Africa (Nersa), as part of the Electricity Regulations Act.
When the first edition of the NRS048-9 code was established in 2010, load shedding stages were capped at Stage 4—representing 25% of the base load—requiring utilities to “find” electricity under emergency conditions.
The need for Stage 6 load shedding in 2019 prompted the NRS 048-9 Work Group to consider extending the load shedding stages to manage load shedding to Stage 8 (Edition 2).
In Stage 8, half the electricity load is shed, and the other half is waiting to be shed.
Now, with the third edition, the full load (minus critical load) is divided up into stages, which now span from stage 1 to stage 16.
While introducing 16 stages of load shedding is the key change in the new regulations, there are many other changes, including giving more flexibility around load curtailment and making provision for smart metering.
Braodly, the changes cover:
- Consolidation of the load shedding stages into a single system from stage 1 to 16, restricting all licensees to using this system as specified in this code of practice, or being able to explain to NERSA why they do not and how their specific system still adheres to the principles herein.
- Clarification on methods for setting baselines for curtailment customers.
- Increased control of how load shedding and load curtailment are determined and carried out, providing more stability to the network and more certainty to curtailment customers.
- Inclusion of the right for curtailment customers to reduce by 10% per stage (2 stages of load shedding), up to stage 10, 50% of their load, or to go to essential loads, depending on their own capacity, rather than being forced to essential loads after Stage 4.
- The specification of compliance and reporting requirements (general and real-time);
- Guidance on the implementation of smart metering as a technology platform for reducing the impact of load shedding on customers; and
- Extensive editorial changes to this specification.
New load shedding stages
The key change in the document comes in extending load shedding stages to stage 16 – but the structure of the new stages may be unfamiliar to what most South Africans have become accustomed to.
At present, most South Africans understand each stage of load shedding to reflect 1,000MW of power that is removed from the grid.
However, under the new structure, this is rather expressed as the percentage of demand assumed by the System Operator at the time the stage is called. The percentages range from 5% of demand at stage 1 to 80% at stage 16.
The new edition also makes no mention of specific ranges (ie, +/- 1,000MW) as is the case in the previous code.
The new schedules also include the structure for customers who are part of the load curtailment programme.
The latest edition also offers a lot more room to load shedding alternatives, including “technology options” such as curtailment using load limiting relays, which will allow for schedules to adjusted.
For example, larger residential areas may rather be subject to curtailment than shedding for the same
load requirement to be achieved.
With the new guidelines published, it will be up to Eskom and municipalities to adjust their schedules to match the new requirements.
The new stages are as follows:
Stage | Reduction required through load shedding | Reduction required through curtailment |
1 | All stage 1 load scheduled by utilities 5% of demand | 10% reduction in normal demand profile |
2 | All stage 2 load scheduled by utilities 10% of demand | 10% reduction in normal demand profile |
3 | All stage 3 load scheduled by utilities 15% of demand | 15% reduction in normal demand profile |
4 | All stage 4 load scheduled by utilities 20% of demand | 20% reduction in normal demand profile |
5 | All stage 5 load scheduled by utilities 25% of demand | 30% reduction in normal demand profile |
6 | All stage 6 load scheduled by utilities 30% of demand | 30% reduction in normal demand profile |
7 | All stage 7 load scheduled by utilities 35% of demand | 40% reduction in normal demand profile |
8 | All stage 8 load scheduled by utilities 40% of demand | 40% reduction in normal demand profile |
9 | All stage 9 load scheduled by utilities 45% of demand | 50% reduction in normal demand profile |
10 | All stage 10 load scheduled by utilities 50% of demand | 50% reduction in normal demand profile |
11 | All stage 11 load scheduled by utilities 55% of demand | Reduction to essential loads or as instructed by SO |
12 | All stage 12 load scheduled by utilities 60% of demand | Reduction to essential loads or as instructed by SO |
13 | All stage 13 load scheduled by utilities 65% of demand | Reduction to essential loads or as instructed by SO |
14 | All stage 14 load scheduled by utilities 70% of demand | Reduction to essential loads or as instructed by SO |
15 | All stage 15 load scheduled by utilities 75% of demand | Reduction to essential loads or as instructed by SO |
16 | All stage 16 load scheduled by utilities 80% of demand | Reduction to essential loads or as instructed by SO |
The full document is embedded below: