While Eskom predicted higher electricity usage because of a cold front passing over most of the country this week, the eThekwini Municipality could foresee no problems because of the weather.
Eskom said in its most recent system status bulletin that it was making progress in terms of a programme of preventive maintenance.
Peak demand for the week was forecast to reach 35 207MW on Wednesday, 35 055MW on Thursday, 33 229MW onFriday, 31 548MW on Saturday and 31 721MW on Sunday.
Eskom had 37 774MW of capacity available, including from open-cycle gas turbines, and current planned maintenance accounted for 3 032MW, while unplanned outages affected 2 397MW.
“From a pure engineering point of view, the city council is not as affected by winter as is Eskom, said the deputy head of the electricity department, Roy Wienand.
“All our transmission lines at high voltage and distribution networks at medium and low voltage are designed for the maximum expected load,” he said.
The city did not expect system constraints in its networks or problems due to the cold weather, but normal faults owing to cable damage by contractors digging in road reserves and cable theft (which is now a huge problem) happen all year round, Wienand added.
Leshan Moodliar, a senior engineer at the department, said Eskom was the generator of electricity.
The state utility was responsible for burning coal, diesel and other fuel sources to generate electricity, but the power generated was then transported to eThekwini via transmission lines.
He said additional generation capacity was only scheduled to come online in stages within the next one to five years.
“Once the power enters Durban, we start transforming the power to lower voltages and provide an electricity supply to customers.”
The capacity of power stations was limited and the country was in a supply-demand constraint, he noted.
Pressure
“So the effects of higher loads will place additional pressure on Eskom’s power stations. eThekwini does not have (to generate power) and so increased usage will only have an effect on our network and its ability to carry the increased loads.
“Cold fronts in particular lead to the extensive use of heating apparatus that drives up the demand for electricity.”
This increased electricity usage would mean more electricity flow through the network.
However, because of constant upgrades and maintenance, networks were adequately sized and would be able to cater for the increased loads during the winter months.
“(All) substations have back-up circuits. In the event of a single fault we could quickly and easily switch to the back-up circuit to restore power while the fault is fixed, thus ensuring that outage times are kept to a minimum.”
Customers in Durban generally used an average of 4 to 5 percent more electricity in the colder winter months than the summer months.
“With Durban’s average temperature during winter always in the double digits, we tend not to see too much of a variation in electricity usage in these months as opposed to cities in colder climates.”
Durban did not experience the symptoms of extreme cold (snow, severe frost, etc), so the reliability of the network during the winter months was high when compared to other cities.
“Durban has a diverse customer base, ranging from residential and business to light commercial and heavy industrial. Each sector has its own peak times based on its usage pattern. However, holistically, the morning peak in Durban is between 7am and 10am and, in the evening from 6pm to 8pm.”
The department encouraged people to adopt a culture of energy savings.
“If everyone works together in using electricity sparingly we could avert countrywide blackouts and its negative economic and social impacts.”