Power cuts make no sense
DISRUPTION: TO MINIMISE IMPACT, OUTAGES NEED TO BE PREDICTABLE
Attempts to pause load shedding during peak traffic introduces unnecessary risk.
As the possibly of permanent round of stage 2 load shedding kicked in at the end of January, Eskom attempted to ensure that there would be no load shedding during the morning peak (6-9am).
At the time, it said this was “an effort to minimise the impact on traffic”. In the first week of February, it also attempted to ensure that load shedding would be artificially halted from 4-6pm to “ease traffic congestion”.
Eskom said: “Suspending loadshedding during the peak traffic hours is a pilot programme aimed at achieving an appropriate load shedding philosophy for the country. As this is not possible every day, it will be confirmed each day, dependent on the risk based on the available capacity and emergency reserves on the day.”
Aside from the inanity of describing this as an “appropriate load shedding philosophy”, there are several problems with this short-lived plan.
First off, load shedding is a function of the shortfall between demand and available supply.
Given stubbornly high plant breakdowns, the inability to forgo planned maintenance any longer, as well as higher-than-average demand, Eskom is simply not able to meet current demand.
Emergency reserves – pumped storage schemes and (diesel-powered) open cycle gas turbines (OCGTs) – are being used to keep the lights on, while maintaining an appropriate operating margin.
Eskom cannot use every megawatt of supply it has at a given point in time in case units trip.
Following a strategy where it artificially halts load shedding during peak traffic hours creates a hugely problematic public misconception that Eskom can control load shedding.
Just days into Eskom’s “pilot programme”, it was unable to “pause” load shedding due to a shortage of generating capacity.
The peak time periods for traffic also conflict directly with metro, municipal and Eskom-direct schedules across the country.
Some run four-hour blocks, others two-hour ones. Most start and end on even hours (4pm, for example), but some start and end on odd hours. This means the “pauses” directly conflict with lots of municipal schedules.
Also, how does a municipality or metro plan to implement – or not implement – load shedding based on notifications from Eskom that arrive at 10pm the previous night or later?
Operationally, trying to halt load shedding for two, three or five hours a day introduces a massive and unnecessary risk.
It cannot magically generate the assumed 2 000MW shortfall at 6am or at 4pm. There is a gradual build-up of capacity, especially when it comes to coal baseload plants. Only emergency plants (pumped storage and OCGTs) can provide power relatively instantly, and Eskom needs to try and keep this proverbial powder dry.
There is zero intelligence to load shedding schedules, save for the City of Cape Town’s decision to not load-shed in the City Bowl.
Rather, we rely on dogmatic Excel spreadsheets that stack blocks in a systematic pattern across the days of the month. This is an “attempt” to make load shedding “fair”.
To minimise the impact of the near-permanent load shedding that will be required over the next 12 to 18 months, it needs to be entirely predictable.
Metros and municipalities around the country need to know exactly what to expect, and when.
PROBLEMATIC. Eskom’s plan to artificially halt load shedding during peak traffic hours creates the misconception that it can control load shedding.