Johannesburg City Power trials load limiting through smart meters
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Johannesburg City Power trials load limiting through smart meters
The mayor of Johannesburg estimates that if all of City Power's 330,000 residential customers had load-limiting smart meters, the utility could save 775MW

In South Africa, Johannesburg electricity utility City Power is piloting a load-limiting programme for residents with smart meters in an attempt to ensure households maintain power supply amid rolling national blackouts.

The load-limiting model - the first of its kind in South Africa - is being piloted in 83 houses before it is expanded to all smart meters in City Power's service area later this year, reports local media BDLive.

City Power plans to use the demand-response functionality of smart meters to warn residents of imminent controlled outages, known locally as load shedding, requesting them to limit their electricity consumption.

The meters are also designed to automatically trip power if consumption exceeds the limit imposed to offset load shedding.

Electricity savings from load limiting

Sicelo Xulu, managing director of City Power, who this week visited the pilot site in the Aspen Hills Nature Reserve complex, near Booysens, said if all 65,000 households with smart meters in its service area implemented load limiting, the city could make a saving of 153MW. This is enough to power more than 20,000 households.

Mr Xulu said: "Based on smart meter penetration, you can yield a saving of 153MW. For the past month we have taken off Kelvin [power station] and the ripple controller and we have been able to offset stage-one load shedding."

The city utility has sought solutions as state utility Eskom increasingly implements controlled blackouts due to insufficient electricity generation from ailing infrastructure.

Since January 2015, City Power has bought independent power from its Kelvin power station and introduced time-of-use-tariffs.

It has also installed 100,000 ripple controller hot-water tanks across the city, which allow the utility to switch off boilers when demand is exceeding supply.

Customer engagement with energy efficiency

Johannesburg Mayor Parks Tau said the load-limiting model, along with other measures, had the added benefit of changing consumers’ behaviour, which would translate to lighter bills, BDLive reported.

Mr Tau said: "We want people to adapt their practices in a manner that spreads the load. You would shift some of your energy consumption and costs in your home to off-peak periods where charges will be cheaper. You can bring down your overall bill by changing and adapting to the time of use tariff."

Tau said that if all 330,000 City Power households in Johannesburg were to implement load limiting, with the use of a smart meter, the city could save at least 775MW, which was more than the amount Kelvin power station generated.