The City of Johannesburg’s electricity supply utility, City Power, has warned it will impose “load reduction” on residents to “protect the grid from total collapse”.

It will implement “stringent measures” – including load reduction in areas with “exceedingly high usage levels” – to ensure the continued integrity of the system amid high demand as the 2024 winter cold sets in.

This is despite Eskom not implementing load shedding for more than 10 weeks, and with no power cuts planned by the national electricity utility.

The measures City Power intends taking include “intensifying the implementation of ripple relay systems to cut electricity to geysers in homes where the system is under threat, reducing load at substations with higher consumption and those under threat, and intensifying cut-off operations against illegal connections”, the company said in a statement at the weekend.

“City Power will implement load reduction starting on Monday, 10 June. Load reduction will be implemented during peak times from 6am to 10am and 4am to 10pm in high-density areas and suburbs with concerning usage levels that threaten to overload the electricity equipment,” it said.

“Load Limiting, through smart meters, will also be implemented in July to further assist customers in saving energy without switching them off completely.”

It said the decision to initiate load reduction follows “extensive efforts to encourage customers to use electricity wisely and efficiently in recent weeks”.

Ripple relays

“Despite warnings about the constrained electricity network in the city, residents have not reduced their electricity consumption, and energy demand has continued to rise.”

Part of its measures to lighten the load on the grid through load reduction includes the installation of ripple relays. A ripple receiver, City Power explained, is part of a load management system used to control the electricity supply to geysers during peak hours.

“Geysers are among the biggest electricity guzzlers, accounting for up to 50% of monthly household energy costs. These ripple relay receivers at different households are connected to at least 69 of our substations, and we can monitor customers’ consumption load remotely,” it said. “City Power will remotely switch off the customer geyser once they reach high consumption levels.”

The utility said it has seen a huge increase in the average evening peak, with some areas rising by up to 110%. “Our network is now at critical levels due to continuous demand, which is higher than the electricity equipment can withstand. As a result, load reduction will be implemented in areas where the load exceeds the designated maximum capacity of our transformers, transmission lines or cables.”

More than 80 areas will be affected and grouped into six blocks for load reduction, which will not exceed two-and-a-half hours per block. The schedule will be implemented during peak hours, in the mornings between 4am to 10am and the evenings between 4pm and 10pm.

“City Power is implementing load reduction as the last resort, an urgent and unavoidable necessity to protect the electricity infrastructure from overloading which can lead to the equipment exploding or catching fire and resulting in prolonged widespread outages and delays that will incur in repairing the damages and replacing the equipment.”

City Power has published a load reduction schedule, which is available on its website (PDF). The company has encouraged Johannesburg residents to check the schedule to determine if and how they are affected. – © 2024 NewsCentral Media