WATCH | How City Power will control your home electricity usage, and why it thinks you will sign up

City Power is planning to roll out smart meters to Johannesburg homes that will control customers' electricity use by targeting energy-hungry appliances.

The metro's power utility said its "load-limiting" system will be an improvement on the enforced power cuts imposed by Eskom.

“Instead of switching off the entire house [as Eskom's load-shedding does], we would like to keep the minimum electricity use to your lights, television, and Wi-Fi," said City Power’s executive  energy management Meyrick Ramatlo.

The load0limiting system will start with the roll-out of 115,000 smart meters to homes in addition to the 30,000 previously installed in the city.

How the load-limiting process works 

When Eskom notifies City Power of the need to reduce electricity use, as it does when it needs to impose load-shedding, City Power will initiate the load-limiting process by sending an SMS and customer interface unit notification to the customer  indicating the percentage reduction required.  

City Power will then activate the process of reducing the load to limit the impact of load-shedding.  

Smart meter  

The smart meter will monitor the load in the house, and if the in-house load is below the load-limit threshold, the electricity supply will remain. 

If the in-house load is above the load-limit threshold, the smart meter will disconnect the main electricity supply. The smart meter will continue to monitor the supply of in-house load and if the amount of load is acceptable, power will be restored.  

What is required from customers 

Residents are required to adhere to messages received from City Power and switch off appliances.

Edward Malatsi from the entity’s ICT department said the smart meter calculates if the customer is under or above the use threshold.

“If the customer is above the threshold, the meter automatically switches off the customer. It waits for 30 seconds for the customer to reduce the load and switch off high-consuming appliances,” he said. 

Malatsi said the cycle happens five times on/off.

If the customer doesn’t adhere to the instructions, it will automatically switch off the customer for 30 minutes and restart the cycle. When the amount of load is acceptable, power will be restored.  

Incentive

If Eskom imposes load-shedding, City Power said switching off high-energy appliances through load-limiting will allow it to ease the pain.

Between peak times — from 5am until 10am and from 5pm until 9pm — residents would be able to use their lights (maximum 1,100W), TV, power a cellphone charger, electric fence, security gate, alarm system and garage door.

In the off-peak time — from 10am to 5pm and from 9pm to 5am — residents would also be able to switch on the geyser and smaller microwaves (under 600W power consumption).

City Power spokesperson Isaac Mangena said should the programme work as planned, it will assist  the City of Johannesburg to offset enforced power outages until stage three or four.  

“When Eskom starts implementing higher stages or goes to stage five and stage six we will start with stage one. Ours [enforced outages] will basically always be three or four stages behind because of the extra capacity we would have received or saved in terms of what we are trying to implement,” he said.   

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