Load shedding vs load reduction – differences explained

 ·10 Jul 2024

Power utility Eskom announced the implementation of load reduction in seven provinces this week, sparking concerns that scheduled power outages had returned to South Africa.

However, Eskom stressed that load reduction is not load shedding, with the improved generation at the group’s power stations having enough capacity to meet national demand.

Instead, load rotation is more of a localised issue, with damaged or overloaded infrastructure in certain areas not being able to handle the increased demand in high-risk areas.

The spike in demand is due to much colder weather hitting the country this week, with Eskom flagging issued in:

  • Limpopo
  • Western Cape
  • Eastern Cape
  • Gauteng
  • Mpumalanga
  • KwaZulu-Natal
  • North West

On top of the demand, criminality and neglect play a significant role in load reduction as well.

While the widespread power cuts brought by load reduction will be new to many areas, the City of Johannesburg has been implementing the cuts for over a month.

With load reduction, the city can cut the electricity usage of households when it notices excessive power consumption within its area of jurisdiction. This may be the entire city or specific areas within the city.

“This is to protect the integrity of its infrastructure—substations, transformers, cables, etc—and prevents explosions, fires, damage to property, including loss of life because of an overload,” it said.

Excessive electricity consumption is prevalent during winter when consumers use heaters, air conditioning and even ovens to keep warm.

Illegal electricity connections, meter bypassing, theft, and vandalism are also contributing factors to overloading the electricity network.

“Residents who are illegally connected to the network do not pay for the electricity they use and thus have no financial burden or moral obligation to pay like the honest residents who are mindful of how electricity is used,” the city said.

“Areas where this practice is rife are the highest consumers of electricity.”

Thus, the infrastructure is unable to cope with the electricity demand, which can result in extensive damage to equipment that is very expensive to repair or replace.

The city highlighted the various measures that can be put in place to curb this, including load shedding, load reducing and load limiting – and the differences between them.


Load Shedding

Load shedding is implemented by Eskom when the national electricity grid is under pressure due to a huge demand for power but there is insufficient capacity to generate electricity for the demand.

This is implemented on a national scale.

Load shedding can last up to eight hours, depending on the different stages implemented to manage electricity demand and protect the grid from collapse.

Municipalities are legally obliged to conform and accordingly implement load shedding within their areas.


Load Reduction

Load reduction cuts off electricity to areas that have excessive electricity usage by residents who are illegally connected to the network.

This is implemented on a more localised scale – ranging from entire cities to specific suburbs and areas.

Cities usually flag a large number of known areas that are complicit in this practice, making load reduction a logical measure that can be implemented during or outside of load shedding hours.


Load Limiting

Load limiting reduces a house’s electricity usage by curtailing its maximum permitted current from 60amps to a minimum of 10amps.

This is implemented on an even more localised scale, usually within a suburb or specific complex where possible.

This allows a household to still have enough electricity for lights, fridges, television, computers and routers and possibly a microwave or kettle—much like having a 5kva inverter.


Load Curtailment

This is implemented based on an agreement, often signed between a power utility (Eskom, City Power, etc.)r, businesses, Large Power Users (LPUs) and essential services such as hospitals and water boards.

This means businesses agree to reduce production during certain periods, for a short period to alleviate grid pressure without suffering from Load reduction or Load shedding.

This is only implemented where these agreements exist.


Peak Hours

According to Eskom and the CoJ, the most common times that load reduction, limiting, and curtailment take place are in peak hours.

The two most recorded peak hours are from 05h00 to 07h00 in the morning and 17h00 to 19h00 in the evening.

These are the times when families are preparing to go to work, school and need to use the lights, microwave, kettle, stove, heaters, iron and again in the evening including other appliances.

Electricity infrastructure must be able to meet the demands of specific areas and is built in a manner to cope with loads equal to the demand.

Load shedding is implemented on a set schedule that covers different blocks during different times of the day for various regions.

Example of load shedding vs load reduction

For load shedding, if the national grid cannot meet demand, load shedding is implemented and all municipalities will have to ensure power is switched off according to a set schedule based on the stage it is set at.

At stage 2, for example, all areas should experience two 2-hour blocks of load shedding on that given day.

With load reduction, if 1,000 houses, including a shopping mall, petrol station, two shopping centres, three schools and several community facilities, are served by an 11kva substation with legal connections, there is little risk of overload, as there is sufficient capacity.

However, if there is a sudden surge in demand (due to winter weather) or an increase in illegal connections, vandalism, or cable theft, the substation is likely to become overloaded and explode.

This area would then be subject to load reduction as the installed infrastructure is not sufficient to serve the added demand from illegal activity.

While many of these issues are externalised by the utilities (ie, blame shifted to illegal connections etc), energy minister Kgosientsho Ramokgopa has also blamed the utilities and municipalities themselves for failing to maintain and invest in their distribution infrastructure.

Old and neglected equipment is also prone to more frequent failure, which could result in load reduction needing to be implemented.


Read: The next crisis threatening to collapse Eskom

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